src/compatibility/4.2/android-4.2-cdd.xhtml - platform/docs/source.android.com - Git at Google


            
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            <title>Android 4.2Compatibility Definition</title>

            
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            <div><img src="header.jpg" alt="Android logo"/></div>

            
            <h1>Android 4.2 Compatibility Definition</h1>

            
            <!--

            
            <span style="color: red; font-weight: bold;"><h2>Revision 1</h2></span><br/>

            
            <span style="color: red;">Last updated: October 17, 2012</span>

            
            -->

            
            <p><b><font color="red">Revision 2</font></b><br/>

            
            Last updated: Feb 17, 2013

            
            </p>

            
            <p>Copyright &copy; 2012, Google Inc. All rights reserved.<br/>

            
            <a href="mailto:compatibility@android.com">compatibility@android.com</a>

            
            </p>


            <h2> Table of Contents</h2>

            
            <div style="margin-left: 2em;">

            
              <a href="#section-1">1. Introduction</a><br/>

            
              <a href="#section-2">2. Resources</a><br/>

            
              <a href="#section-3">3. Software</a><br/>

            
              <div style="margin-left: 2em;">

            
                <a href="#section-3.1">3.1. Managed API Compatibility</a><br/>

            
                <a href="#section-3.2">3.2. Soft API Compatibility</a><br/>

            
                <div style="margin-left: 2em;">

            
                  <a href="#section-3.2.1">3.2.1. Permissions</a><br/>

            
                  <a href="#section-3.2.2">3.2.2. Build Parameters</a><br/>

            
                  <a href="#section-3.2.3">3.2.3. Intent Compatibility</a><br/>

            
                  <div style="margin-left: 2em;">

            
                    <a href="#section-3.2.3.1">3.2.3.1. Core Application Intents</a><br/>

            
                    <a href="#section-3.2.3.2">3.2.3.2. Intent Overrides</a><br/>

            
                    <a href="#section-3.2.3.3">3.2.3.3. Intent Namespaces</a><br/>

            
                    <a href="#section-3.2.3.4">3.2.3.4. Broadcast Intents</a><br/>

            
                  </div>

            
                </div>

            
                <a href="#section-3.3">3.3. Native API Compatibility</a><br/>

            
                <div style="margin-left: 2em;">

            
                  <a href="#section-3.3.1">3.3.1 Application Binary Interfaces</a><br/>

            
                </div>

            
                <a href="#section-3.4">3.4. Web Compatibility</a><br/>

            
                <div style="margin-left: 2em;">

            
                  <a href="#section-3.4.1">3.4.1. WebView Compatibility</a><br/>

            
                  <a href="#section-3.4.2">3.4.2. Browser Compatibility</a><br/>

            
                </div>

            
                <a href="#section-3.5">3.5. API Behavioral Compatibility</a><br/>

            
                <a href="#section-3.6">3.6. API Namespaces</a><br/>

            
                <a href="#section-3.7">3.7. Virtual Machine Compatibility</a><br/>

            
                <a href="#section-3.8">3.8. User Interface Compatibility</a><br/>

            
                <div style="margin-left: 2em;">

            
                  <a href="#section-3.8.1">3.8.1. Widgets</a><br/>

            
                  <a href="#section-3.8.2">3.8.2. Notifications</a><br/>

            
                  <a href="#section-3.8.3">3.8.3. Search</a><br/>

            
                  <a href="#section-3.8.4">3.8.4. Toasts</a><br/>

            
                  <a href="#section-3.8.5">3.8.5. Themes</a><br/>

            
                  <a href="#section-3.8.6">3.8.6. Live Wallpapers</a><br/>

            
                  <a href="#section-3.8.7">3.8.7. Recent Application Display</a><br/>

            
                  <a href="#section-3.8.8">3.8.8. Input Management Settings</a><br/>

            
                  <a href="#section-3.8.9">3.8.9. Lock and Home Screen Widgets</a><br/>

            
                  <a href="#section-3.8.10">3.8.10. Lock Screen Media Remote Control</a><br/>

            
                  <a href="#section-3.8.11">3.8.11. Dreams</a><br/>

            
                </div>

            
                <a href="#section-3.9">3.9 Device Administration</a><br/>

            
                <a href="#section-3.10">3.10 Accessibility</a><br/>

            
                <a href="#section-3.11">3.11 Text-to-Speech</a><br/>

            
              </div>

            
              <a href="#section-4">4. Application Packaging Compatibility</a><br/>

            
              <a href="#section-5">5. Multimedia Compatibility</a><br/>

            
                <div style="margin-left: 2em;">

            
                  <a href="#section-5.1">5.1. Media Codecs</a><br/>

            
                  <a href="#section-5.2">5.2. Video Encoding</a><br/>

            
                  <a href="#section-5.3">5.3. Video Decoding</a><br/>

            
                  <a href="#section-5.4">5.4. Audio Recording</a><br/>

            
                  <a href="#section-5.5">5.5. Audio Latency</a><br/>

            
                  <a href="#section-5.6">5.6. Network Protocols</a><br/>

            
                </div>

            
              <a href="#section-6">6. Developer Tools and Options Compatibility</a><br/>

            
                <div style="margin-left: 2em;">

            
                  <a href="#section-6.1">6.1. Developer Tools</a><br/>

            
                  <a href="#section-6.2">6.2. Developer Options</a><br/>

            
                </div>

            
              <a href="#section-7">7. Hardware Compatibility</a><br/>

            
              <div style="margin-left: 2em;">

            
                <a href="#section-7.1">7.1. Display and Graphics</a><br/>

            
                <div style="margin-left: 2em;">

            
                  <a href="#section-7.1.1">7.1.1. Screen Configuration</a><br/>

            
                  <a href="#section-7.1.2">7.1.2. Display Metrics</a><br/>

            
                  <a href="#section-7.1.3">7.1.3. Screen Orientation</a><br/>

            
                  <a href="#section-7.1.4">7.1.4. 2D and 3D Graphics Accleration</a><br/>

            
                  <a href="#section-7.1.5">7.1.5. Legacy Application Compatibility Mode</a><br/>

            
                  <a href="#section-7.1.6">7.1.6. Screen Types</a><br/>

            
                  <a href="#section-7.1.7">7.1.7. Screen Technology</a><br/>

            
                  <a href="#section-7.1.8">7.1.8. External Displays</a><br/>

            
                </div>

            
                <a href="#section-7.2">7.2. Input Devices</a><br/>

            
                <div style="margin-left: 2em;">

            
                  <a href="#section-7.2.1">7.2.1. Keyboard</a><br/>

            
                  <a href="#section-7.2.2">7.2.2. Non-touch Navigation</a><br/>

            
                  <a href="#section-7.2.3">7.2.3. Navigation keys</a><br/>

            
                  <a href="#section-7.2.4">7.2.4. Touchscreen input</a><br/>

            
                </div>

            
                <a href="#section-7.3">7.3. Sensors</a><br/>

            
                <div style="margin-left: 2em;">

            
                  <a href="#section-7.3.1">7.3.1. Accelerometer</a><br/>

            
                  <a href="#section-7.3.2">7.3.2. Magnetometer</a><br/>

            
                  <a href="#section-7.3.3">7.3.3. GPS</a><br/>

            
                  <a href="#section-7.3.4">7.3.4. Gyroscope</a><br/>

            
                  <a href="#section-7.3.5">7.3.5. Barometer</a><br/>

            
                  <a href="#section-7.3.6">7.3.6. Thermometer</a><br/>

            
                  <a href="#section-7.3.7">7.3.7. Photometer</a><br/>

            
                  <a href="#section-7.3.8">7.3.8. Proximity Sensor</a><br/>

            
                </div>

            
                <a href="#section-7.4">7.4. Data Connectivity</a><br/>

            
                <div style="margin-left: 2em;">

            
                  <a href="#section-7.4.1">7.4.1. Telephony</a><br/>

            
                  <a href="#section-7.4.2">7.4.2. IEEE 802.11 (WiFi)</a><br/>

            
                  <div style="margin-left: 2em;">

            
                    <a href="#section-7.4.2.1">7.4.2.1. WiFi Direct</a><br/>

            
                  </div>

            
                  <a href="#section-7.4.3">7.4.3. Bluetooth</a><br/>

            
                  <a href="#section-7.4.4">7.4.4. Near-Field Communications</a><br/>

            
                  <a href="#section-7.4.5">7.4.5. Minimum Network Capability</a><br/>

            
                </div>

            
                <a href="#section-7.5">7.5. Cameras</a><br/>

            
                <div style="margin-left: 2em;">

            
                  <a href="#section-7.5.1">7.5.1. Rear-Facing Camera</a><br/>

            
                  <a href="#section-7.5.2">7.5.2. Front-Facing Camera</a><br/>

            
                  <a href="#section-7.5.3">7.5.3. Camera API Behavior</a><br/>

            
                  <a href="#section-7.5.4">7.5.4. Camera Orientation</a><br/>

            
                </div>

            
                <a href="#section-7.6">7.6. Memory and Storage</a><br/>

            
                <div style="margin-left: 2em;">

            
                  <a href="#section-7.6.1">7.6.1. Minimum Memory and Storage</a><br/>

            
                  <a href="#section-7.6.2">7.6.2. Application Shared Storage</a><br/>

            
                </div>

            
                <a href="#section-7.7">7.7. USB</a><br/>

            
              </div>

            
              <a href="#section-8">8. Performance Compatibility</a><br/>

            
              <a href="#section-9">9. Security Model Compatibility</a><br/>

            
              <div style="margin-left: 2em;">

            
                <a href="#section-9.1">9.1. Permissions</a><br/>

            
                <a href="#section-9.2">9.2. UID and Process Isolation</a><br/>

            
                <a href="#section-9.3">9.3. Filesystem Permissions</a><br/>

            
                <a href="#section-9.4">9.4. Alternate Execution Environments</a><br/>

            
                <a href="#section-9.5">9.5. Multi-User Support</a><br/>

            
                <a href="#section-9.6">9.6. Premium SMS Warning</a><br/>

            
              </div>

            
              <a href="#section-10">10. Software Compatibility Testing</a><br/>

            
              <div style="margin-left: 2em;">

            
                <a href="#section-10.1">10.1. Compatibility Test Suite</a><br/>

            
                <a href="#section-10.2">10.2. CTS Verifier</a><br/>

            
                <a href="#section-10.3">10.3. Reference Applications</a><br/>

            
              </div>

            
              <a href="#section-11">11. Updatable Software</a><br/>

            
              <a href="#section-12">12. Contact Us</a><br/>

            
              <a href="#appendix-A">Appendix A - Bluetooth Test Procedure</a><br/>

            
            </div>


            <div style="page-break-before: always;"></div>


            <a name="section-1"></a><h2>1. Introduction</h2>

            
            <p>This document enumerates the requirements that must be met in order for

            
            devices to be compatible with Android 4.2.</p>

            
            <p>The use of "must", "must not", "required", "shall", "shall not", "should",

            
            "should not", "recommended", "may" and "optional" is per the IETF standard

            
            defined in RFC2119 [<a href="#resources01">Resources, 1</a>].</p>

            
            <p>As used in this document, a "device implementer" or "implementer" is a

            
            person or organization developing a hardware/software solution running Android

            
            4.2. A "device implementation" or "implementation" is the hardware/software

            
            solution so developed.</p>

            
            <p>To be considered compatible with Android 4.2, device implementations

            
            MUST meet the requirements presented in this Compatibility Definition,

            
            including any documents incorporated via reference.</p>

            
            <p>Where this definition or the software tests described in <a

            
            href="#section-10">Section 10</a> is silent, ambiguous, or incomplete, it is

            
            the responsibility of the device implementer to ensure compatibility with

            
            existing implementations.</p>

            
            <p>For this reason, the Android Open Source Project [<a

            
            href="#resources03">Resources, 3</a>] is both the reference and preferred

            
            implementation of Android. Device implementers are strongly encouraged to base

            
            their implementations to the greatest extent possible on the "upstream" source

            
            code available from the Android Open Source Project. While some components can

            
            hypothetically be replaced with alternate implementations this practice is

            
            strongly discouraged, as passing the software tests will become substantially

            
            more difficult. It is the implementer's responsibility to ensure full

            
            behavioral compatibility with the standard Android implementation, including

            
            and beyond the Compatibility Test Suite. Finally, note that certain component

            
            substitutions and modifications are explicitly forbidden by this document.</p>

            
            <a name="section-2"></a><h2>2. Resources</h2>

            
            <ol>

            
            <a name="resources01"></a><li>IETF RFC2119 Requirement Levels: <a href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a></li>

            
            <a name="resources02"></a><li>Android Compatibility Program Overview: <a href="http://source.android.com/compatibility/index.html">http://source.android.com/compatibility/index.html</a></li>

            
            <a name="resources03"></a><li>Android Open Source Project: <a href="http://source.android.com/">http://source.android.com/</a></li>

            
            <a name="resources04"></a><li>API definitions and documentation: <a href="http://developer.android.com/reference/packages.html">http://developer.android.com/reference/packages.html</a></li>

            
            <a name="resources05"></a><li>Android Permissions reference: <a href="http://developer.android.com/reference/android/Manifest.permission.html">http://developer.android.com/reference/android/Manifest.permission.html</a></li>

            
            <a name="resources06"></a><li>android.os.Build reference: <a href="http://developer.android.com/reference/android/os/Build.html">http://developer.android.com/reference/android/os/Build.html</a></li>

            
            <a name="resources07"></a><li>Android 4.2 allowed version strings: <a href="http://source.android.com/compatibility/4.2/versions.html">http://source.android.com/compatibility/4.2/versions.html</a></li>

            
            <a name="resources08"></a><li>Renderscript: <a href="http://developer.android.com/guide/topics/graphics/renderscript.html">http://developer.android.com/guide/topics/graphics/renderscript.html</a></li>

            
            <a name="resources09"></a><li>Hardware Acceleration: <a href="http://developer.android.com/guide/topics/graphics/hardware-accel.html">http://developer.android.com/guide/topics/graphics/hardware-accel.html</a></li>

            
            <a name="resources10"></a><li>android.webkit.WebView class: <a href="http://developer.android.com/reference/android/webkit/WebView.html">http://developer.android.com/reference/android/webkit/WebView.html</a></li>

            
            <a name="resources11"></a><li>HTML5: <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/">http://www.whatwg.org/specs/web-apps/current-work/multipage/</a></li>

            
            <a name="resources12"></a><li>HTML5 offline capabilities: <a href="http://dev.w3.org/html5/spec/Overview.html#offline">http://dev.w3.org/html5/spec/Overview.html#offline</a></li>

            
            <a name="resources13"></a><li>HTML5 video tag: <a href="http://dev.w3.org/html5/spec/Overview.html#video">http://dev.w3.org/html5/spec/Overview.html#video</a></li>

            
            <a name="resources14"></a><li>HTML5/W3C geolocation API: <a href="http://www.w3.org/TR/geolocation-API/">http://www.w3.org/TR/geolocation-API/</a></li>

            
            <a name="resources15"></a><li>HTML5/W3C webdatabase API: <a href="http://www.w3.org/TR/webdatabase/">http://www.w3.org/TR/webdatabase/</a></li>

            
            <a name="resources16"></a><li>HTML5/W3C IndexedDB API: <a href="http://www.w3.org/TR/IndexedDB/">http://www.w3.org/TR/IndexedDB/</a></li>

            
            <a name="resources17"></a><li>Dalvik Virtual Machine specification: available in the Android source code, at dalvik/docs</li>

            
            <a name="resources18"></a><li>AppWidgets: <a href="http://developer.android.com/guide/practices/ui_guidelines/widget_design.html">http://developer.android.com/guide/practices/ui_guidelines/widget_design.html</a></li>

            
            <a name="resources19"></a><li>Notifications: <a href="http://developer.android.com/guide/topics/ui/notifiers/notifications.html">http://developer.android.com/guide/topics/ui/notifiers/notifications.html</a></li>

            
            <a name="resources20"></a><li>Application Resources: <a href="http://code.google.com/android/reference/available-resources.html">http://code.google.com/android/reference/available-resources.html</a></li>

            
            <a name="resources21"></a><li>Status Bar icon style guide: <a href="http://developer.android.com/guide/practices/ui_guidelines/icon_design_status_bar.html">http://developer.android.com/guide/practices/ui_guidelines/icon_design_status_bar.html</a></li>

            
            <a name="resources22"></a><li>Search Manager: <a href="http://developer.android.com/reference/android/app/SearchManager.html">http://developer.android.com/reference/android/app/SearchManager.html</a></li>

            
            <a name="resources23"></a><li>Toasts: <a href="http://developer.android.com/reference/android/widget/Toast.html">http://developer.android.com/reference/android/widget/Toast.html</a></li>

            
            <a name="resources24"></a><li>Themes: <a href="http://developer.android.com/guide/topics/ui/themes.html">http://developer.android.com/guide/topics/ui/themes.html</a></li>

            
            <a name="resources25"></a><li>R.style class: <a href="http://developer.android.com/reference/android/R.style.html">http://developer.android.com/reference/android/R.style.html</a></li>

            
            <a name="resources26"></a><li>Live Wallpapers: <a href="http://developer.android.com/resources/articles/live-wallpapers.html">http://developer.android.com/resources/articles/live-wallpapers.html</a></li>

            
            <a name="resources27"></a><li>Android Device Administration: <a href="http://developer.android.com/guide/topics/admin/device-admin.html">http://developer.android.com/guide/topics/admin/device-admin.html</a></li>

            
            <a name="resources28"></a><li>DevicePolicyManager reference: <a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html">http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html</a></li>

            
            <a name="resources29"></a><li>Android Accessibility Service APIs: <a href="http://developer.android.com/reference/android/accessibilityservice/package-summary.html">http://developer.android.com/reference/android/accessibilityservice/package-summary.html</a></li>

            
            <a name="resources30"></a><li>Android Accessibility APIs: <a href="http://developer.android.com/reference/android/view/accessibility/package-summary.html">http://developer.android.com/reference/android/view/accessibility/package-summary.html</a></li>

            
            <a name="resources31"></a><li>Eyes Free project: <a href="http://http://code.google.com/p/eyes-free">http://code.google.com/p/eyes-free</a></li>

            
            <a name="resources32"></a><li>Text-To-Speech APIs: <a href="http://developer.android.com/reference/android/speech/tts/package-summary.html">http://developer.android.com/reference/android/speech/tts/package-summary.html</a></li>

            
            <a name="resources33"></a><li>Reference tool documentation (for adb, aapt, ddms, systrace): <a href="http://developer.android.com/guide/developing/tools/index.html">http://developer.android.com/guide/developing/tools/index.html</a></li>

            
            <a name="resources34"></a><li>Android apk file description: <a href="http://developer.android.com/guide/topics/fundamentals.html">http://developer.android.com/guide/topics/fundamentals.html</a></li>

            
            <a name="resources35"></a><li>Manifest files: <a href="http://developer.android.com/guide/topics/manifest/manifest-intro.html">http://developer.android.com/guide/topics/manifest/manifest-intro.html</a></li>

            
            <a name="resources36"></a><li>Monkey testing tool: <a href="http://developer.android.com/guide/developing/tools/monkey.html">http://developer.android.com/guide/developing/tools/monkey.html</a></li>

            
            <a name="resources37"></a><li>Android android.content.pm.PackageManager class and Hardware Features List: <a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">http://developer.android.com/reference/android/content/pm/PackageManager.html</a></li>

            
            <a name="resources38"></a><li>Supporting Multiple Screens: <a href="http://developer.android.com/guide/practices/screens_support.html">http://developer.android.com/guide/practices/screens_support.html</a></li>

            
            <a name="resources39"></a><li>android.util.DisplayMetrics: <a href="http://developer.android.com/reference/android/util/DisplayMetrics.html">http://developer.android.com/reference/android/util/DisplayMetrics.html</a></li>

            
            <a name="resources40"></a><li>android.content.res.Configuration: <a href="http://developer.android.com/reference/android/content/res/Configuration.html">http://developer.android.com/reference/android/content/res/Configuration.html</a></li>

            
            <a name="resources41"></a><li>android.hardware.SensorEvent: <a href="http://developer.android.com/reference/android/hardware/SensorEvent.html">http://developer.android.com/reference/android/hardware/SensorEvent.html</a></li>

            
            <a name="resources42"></a><li>Bluetooth API: <a href="http://developer.android.com/reference/android/bluetooth/package-summary.html">http://developer.android.com/reference/android/bluetooth/package-summary.html</a></li>

            
            <a name="resources43"></a><li>NDEF Push Protocol: <a href="http://source.android.com/compatibility/ndef-push-protocol.pdf">http://source.android.com/compatibility/ndef-push-protocol.pdf</a></li>

            
            <a name="resources44"></a><li>MIFARE MF1S503X: <a href="http://www.nxp.com/documents/data_sheet/MF1S503x.pdf">http://www.nxp.com/documents/data_sheet/MF1S503x.pdf</a></li>

            
            <a name="resources45"></a><li>MIFARE MF1S703X: <a href="http://www.nxp.com/documents/data_sheet/MF1S703x.pdf">http://www.nxp.com/documents/data_sheet/MF1S703x.pdf</a></li>

            
            <a name="resources46"></a><li>MIFARE MF0ICU1: <a href="http://www.nxp.com/documents/data_sheet/MF0ICU1.pdf">http://www.nxp.com/documents/data_sheet/MF0ICU1.pdf</a></li>

            
            <a name="resources47"></a><li>MIFARE MF0ICU2: <a href="http://www.nxp.com/documents/short_data_sheet/MF0ICU2_SDS.pdf">http://www.nxp.com/documents/short_data_sheet/MF0ICU2_SDS.pdf</a></li>

            
            <a name="resources48"></a><li>MIFARE AN130511: <a href="http://www.nxp.com/documents/application_note/AN130511.pdf">http://www.nxp.com/documents/application_note/AN130511.pdf</a></li>

            
            <a name="resources49"></a><li>MIFARE AN130411: <a href="http://www.nxp.com/documents/application_note/AN130411.pdf">http://www.nxp.com/documents/application_note/AN130411.pdf</a></li>

            
            <a name="resources50"></a><li>Camera orientation API: <a href="http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)">http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)</a></li>

            
            <a name="resources51"></a><li>Camera: <a href="http://developer.android.com/reference/android/hardware/Camera.html">http://developer.android.com/reference/android/hardware/Camera.html</a></li>

            
            <a name="resources52"></a><li>Android Open Accessories: <a href="http://developer.android.com/guide/topics/usb/accessory.html">http://developer.android.com/guide/topics/usb/accessory.html</a></li>

            
            <a name="resources53"></a><li>USB Host API: <a href="http://developer.android.com/guide/topics/usb/host.html">http://developer.android.com/guide/topics/usb/host.html</a></li>

            
            <a name="resources54"></a><li>Android Security and Permissions reference: <a href="http://developer.android.com/guide/topics/security/security.html">http://developer.android.com/guide/topics/security/security.html</a></li>

            
            <a name="resources55"></a><li>Apps for Android: <a href="http://code.google.com/p/apps-for-android">http://code.google.com/p/apps-for-android</a></li>

            
            <a name="resources56"></a><li>Android DownloadManager: <a href="http://developer.android.com/reference/android/app/DownloadManager.html">http://developer.android.com/reference/android/app/DownloadManager.html</a></li>

            
            <a name="resources57"></a><li>Android File Transfer: <a href="http://www.android.com/filetransfer">http://www.android.com/filetransfer</a></li>

            
            <a name="resources58"></a><li>Android Media Formats: <a href="http://developer.android.com/guide/appendix/media-formats.html">http://developer.android.com/guide/appendix/media-formats.html</a></li>

            
            <a name="resources59"></a><li>HTTP Live Streaming Draft Protocol: <a href="http://tools.ietf.org/html/draft-pantos-http-live-streaming-03">http://tools.ietf.org/html/draft-pantos-http-live-streaming-03</a></li>

            
            <a name="resources60"></a><li>NFC Connection Handover: <a href="http://www.nfc-forum.org/specs/spec_list/#conn_handover/">http://www.nfc-forum.org/specs/spec_list/#conn_handover</a></li>

            
            <a name="resources61"></a><li>Bluetooth Secure Simple Pairing Using NFC: <a href="http://www.nfc-forum.org/resources/AppDocs/NFCForum_AD_BTSSP_1_0.pdf">http://www.nfc-forum.org/resources/AppDocs/NFCForum_AD_BTSSP_1_0.pdf</a></li>

            
            <a name="resources62"></a><li>Wifi Multicast API: <a href="http://developer.android.com/reference/android/net/wifi/WifiManager.MulticastLock.html">http://developer.android.com/reference/android/net/wifi/WifiManager.MulticastLock.html</a></li>

            
            <a name="resources63"></a><li>Action Assist: <a href="http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST">http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST</a></li>

            
            <a name="resources64"></a><li>USB Charging Specification: <a href="http://www.usb.org/developers/devclass_docs/USB_Battery_Charging_1.2.pdf">http://www.usb.org/developers/devclass_docs/USB_Battery_Charging_1.2.pdf</a></li>

            
            <a name="resources65"></a><li>Android Beam: <a href="http://developer.android.com/guide/topics/nfc/nfc.html">http://developer.android.com/guide/topics/nfc/nfc.html</a></li>

            
            <a name="resources66"></a><li>Android USB Audio: <a href="http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO">http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO</a></li>

            
            <a name="resources67"></a><li>Android NFC Sharing Settings: <a href="http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFCSHARING_SETTINGS">http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFCSHARING_SETTINGS</a></li>

            
            <a name="resources68"></a><li>Wifi Direct (Wifi P2P): <a href="http://developer.android.com/reference/android/net/wifi/p2p/WifiP2pManager.html">http://developer.android.com/reference/android/net/wifi/p2p/WifiP2pManager.html</a></li>

            
            <a name="resources69"></a><li>Lock and Home Screen Widget: <a href="http://developer.android.com/reference/android/appwidget/AppWidgetProviderInfo.html">http://developer.android.com/reference/android/appwidget/AppWidgetProviderInfo.html</a></li>

            
            <a name="resources70"></a><li>UserManager reference: <a href="http://developer.android.com/reference/android/os/UserManager.html">http://developer.android.com/reference/android/os/UserManager.html</a></li>

            
            <a name="resources71"></a><li>External Storage reference: <a href="http://source.android.com/tech/storage">http://source.android.com/tech/storage</a></li>

            
            <a name="resources72"></a><li>External Storage APIs: <a href="http://developer.android.com/reference/android/os/Environment.html">http://developer.android.com/reference/android/os/Environment.html</a></li>

            
            <a name="resources73"></a><li>SMS Short Code: <a href="http://en.wikipedia.org/wiki/Short_code">http://en.wikipedia.org/wiki/Short_code</a></li>

            
            <a name="resources74"></a><li>Media Remote Control Client: <a href="http://developer.android.com/reference/android/media/RemoteControlClient.html">http://developer.android.com/reference/android/media/RemoteControlClient.html</a></li>

            
            <a name="resources75"></a><li>Display Manager: <a href="http://developer.android.com/reference/android/hardware/display/DisplayManager.html">http://developer.android.com/reference/android/hardware/display/DisplayManager.html</a></li>

            
            <a name="resources76"></a><li>Dreams: <a href="http://developer.android.com/reference/android/service/dreams/DreamService.html">http://developer.android.com/reference/android/service/dreams/DreamService.html</a></li>

            
            <a name="resources77"></a><li>Android Application Development-Related Settings: <a href="http://developer.android.com/reference/android/provider/Settings.html#ACTION_APPLICATION_DEVELOPMENT_SETTINGS">http://developer.android.com/reference/android/provider/Settings.html#ACTION_APPLICATION_DEVELOPMENT_SETTINGS</a></li>

            
            </ol>

            
            <a name="resources78"></a><li>Camera: <a href="http://developer.android.com/reference/android/hardware/Camera.Parameters.html">http://developer.android.com/reference/android/hardware/Camera.Parameters.html</a></li>

            
            <p>Many of these resources are derived directly or indirectly from the Android

            
            4.2 SDK, and will be functionally identical to the information in that SDK's

            
            documentation. In any cases where this Compatibility Definition or the

            
            Compatibility Test Suite disagrees with the SDK documentation, the SDK

            
            documentation is considered authoritative. Any technical details provided in

            
            the references included above are considered by inclusion to be part of this

            
            Compatibility Definition.</p>


            <a name="section-3"></a><h2>3. Software</h2>

            
            <a name="section-3.1"></a><h3>3.1. Managed API Compatibility</h3>

            
            <p>The managed (Dalvik-based) execution environment is the primary vehicle for

            
            Android applications. The Android application programming interface (API) is

            
            the set of Android platform interfaces exposed to applications running in the

            
            managed VM environment. Device implementations MUST provide complete

            
            implementations, including all documented behaviors, of any documented API

            
            exposed by the Android 4.2 SDK [<a href="#resources04">Resources, 4</a>].</p>

            
            <p>Device implementations MUST NOT omit any managed APIs, alter API interfaces

            
            or signatures, deviate from the documented behavior, or include no-ops, except

            
            where specifically allowed by this Compatibility Definition.</p>

            
            <p>This Compatibility Definition permits some types of hardware for which

            
            Android includes APIs to be omitted by device implementations. In such cases,

            
            the APIs MUST still be present and behave in a reasonable way. See

            
            <a href="#section-7">Section 7</a> for specific requirements for this scenario.

            
            </p>


            <a name="section-3.2"></a><h3>3.2. Soft API Compatibility</h3>

            
            <p>In addition to the managed APIs from Section 3.1, Android also includes a

            
            significant runtime-only "soft" API, in the form of such things such as

            
            Intents, permissions, and similar aspects of Android applications that cannot

            
            be enforced at application compile time.</p>

            
            <a name="section-3.2.1"></a><h4>3.2.1. Permissions</h4>

            
            <p>Device implementers MUST support and enforce all permission constants as

            
            documented by the Permission reference page [<a

            
            href="#resources05">Resources, 5</a>]. Note that Section 10 lists additional

            
            requirements related to the Android security model.</p>

            
            <a name="section-3.2.2"></a><h4>3.2.2. Build Parameters</h4>

            
            <p>The Android APIs include a number of constants on the <code>android.os.Build</code>

            
            class [<a href="#resources06">Resources, 6</a>] that are intended to describe

            
            the current device. To provide consistent, meaningful values across device

            
            implementations, the table below includes additional restrictions on the

            
            formats of these values to which device implementations MUST conform.</p>

            
            <table>

            
            <tbody>

            
            <tr>

            
            <td><b>Parameter</b></td>

            
            <td><b>Comments</b></td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.VERSION.RELEASE</td>

            
            <td>The version of the currently-executing Android system, in human-readable

            
            format. This field MUST have one of the string values defined in [<a

            
            href="#resources07">Resources, 7</a>].</td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.VERSION.SDK</td>

            
            <td>The version of the currently-executing Android system, in a format

            
            accessible to third-party application code. For Android 4.2, this

            
            field MUST have the integer value 17.</td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.VERSION.SDK_INT</td>

            
            <td>The version of the currently-executing Android system, in a format

            
            accessible to third-party application code. For Android 4.2, this

            
            field MUST have the integer value 17.</td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.VERSION.INCREMENTAL</td>

            
            <td>A value chosen by the device implementer designating the specific build of

            
            the currently-executing Android system, in human-readable format. This value

            
            MUST NOT be re-used for different builds made available to end users. A typical use

            
            of this field is to indicate which build number or source-control change

            
            identifier was used to generate the build. There are no requirements on the

            
            specific format of this field, except that it MUST NOT be null or the empty

            
            string ("").</td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.BOARD</td>

            
            <td>A value chosen by the device implementer identifying the specific internal

            
            hardware used by the device, in human-readable format. A possible use of this

            
            field is to indicate the specific revision of the board powering the device.

            
            The value of this field MUST be encodable as 7-bit ASCII and match the regular expression

            
            <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.BRAND</td>

            
            <td>A value chosen by the device implementer identifying the name of the

            
            company, organization, individual, etc. who produced the device, in

            
            human-readable format. A possible use of this field is to indicate the OEM

            
            and/or carrier who sold the device. The value of this field MUST be

            
            encodable as 7-bit ASCII and match the regular expression

            
            <code>"^[a-zA-Z0-9.,_-]+$"</code>.

            
            </td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.CPU_ABI</td>

            
            <td>The name of the instruction set (CPU type + ABI convention) of native code.

            
            See <a href="#section-3.3">Section 3.3: Native API Compatibility</a>.

            
            </td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.CPU_ABI2</td>

            
            <td>The name of the second instruction set (CPU type + ABI convention) of native code.

            
            See <a href="#section-3.3">Section 3.3: Native API Compatibility</a>.

            
            </td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.DEVICE</td>

            
            <td>A value chosen by the device implementer identifying the specific

            
            configuration or revision of the body (sometimes called "industrial design")

            
            of the device. The value of this field MUST be encodable as 7-bit ASCII and

            
            match the regular expression <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.FINGERPRINT</td>

            
            <td>A string that uniquely identifies this build. It SHOULD be reasonably

            
            human-readable. It MUST follow this template:

            
            <br/><code>$(BRAND)/$(PRODUCT)/$(DEVICE):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS)</code><br/>

            
            For example:

            
            <br/><code>acme/mydevice/generic:4.2/JRN53/3359:userdebug/test-keys</code><br/>

            
            The fingerprint MUST NOT include whitespace characters. If other fields included in the

            
            template above have whitespace characters, they MUST be replaced in the build

            
            fingerprint with another character, such as the underscore ("_") character.

            
            The value of this field MUST be encodable as 7-bit ASCII.</td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.HARDWARE</td>

            
            <td>The name of the hardware (from the kernel command line or /proc).  It SHOULD be

            
            reasonably human-readable. The value of this field MUST be encodable as 7-bit ASCII and

            
            match the regular expression <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.HOST</td>

            
            <td>A string that uniquely identifies the host the build was built on, in

            
            human readable format. There are no requirements on the specific format of

            
            this field, except that it MUST NOT be null or the empty string ("").</td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.ID</td>

            
            <td>An identifier chosen by the device implementer to refer to a specific

            
            release, in human readable format. This field can be the same as

            
            android.os.Build.VERSION.INCREMENTAL, but SHOULD be a value sufficiently

            
            meaningful for end users to distinguish between software builds. The value of

            
            this field MUST be encodable as 7-bit ASCII and match the regular expression

            
            <code>"^[a-zA-Z0-9.,_-]+$"</code>.

            
            </td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.MANUFACTURER</td>

            
            <td>The trade name of the Original Equipment Manufacturer (OEM) of the product.

            
            There are no requirements on the specific format of this field, except that it

            
            MUST NOT be null or the empty string ("").</td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.MODEL</td>

            
            <td>A value chosen by the device implementer containing the name of the device

            
            as known to the end user. This SHOULD be the same name under which the device

            
            is marketed and sold to end users. There are no requirements on the specific

            
            format of this field, except that it MUST NOT be null or the empty string

            
            ("").</td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.PRODUCT</td>

            
            <td>A value chosen by the device implementer containing the development name

            
            or code name of the product (SKU). MUST be human-readable, but is not necessarily

            
            intended for view by end users. The value of this field MUST be encodable as 7-bit

            
            ASCII and match the regular expression

            
            <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.SERIAL</td>

            
            <td>A hardware serial number, if available. The value of this field MUST be encodable

            
            as 7-bit ASCII and match the regular expression

            
            <code>"^([a-zA-Z0-9]{0,20})$"</code>.</td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.TAGS</td>

            
            <td>A comma-separated list of tags chosen by the device implementer that

            
            further distinguish the build. For example, "unsigned,debug". The value of

            
            this field MUST be encodable as 7-bit ASCII and match the regular expression

            
            <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.TIME</td>

            
            <td>A value representing the timestamp of when the build occurred.</td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.TYPE</td>

            
            <td>A value chosen by the device implementer specifying the runtime

            
            configuration of the build. This field SHOULD have one of the values

            
            corresponding to the three typical Android runtime configurations: "user",

            
            "userdebug", or "eng". The value of this field MUST be

            
            encodable as 7-bit ASCII and match the regular expression

            
            <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td>

            
            </tr>

            
            <tr>

            
            <td>android.os.Build.USER</td>

            
            <td>A name or user ID of the user (or automated user) that generated the

            
            build. There are no requirements on the specific format of this field, except

            
            that it MUST NOT be null or the empty string ("").</td>

            
            </tr>

            
            </tbody>

            
            </table>

            
            <a name="section-3.2.3"></a><h4>3.2.3. Intent Compatibility</h4>

            
            <p>

            
            Device implementations MUST honor Android's loose-coupling Intent system, as

            
            described in the sections below. By "honored", it is meant that the device

            
            implementer MUST provide an Android Activity or Service that specifies a

            
            matching Intent filter and binds to and implements correct behavior for each

            
            specified Intent pattern.</p>

            
            <a name="section-3.2.3.1"></a><h4>3.2.3.1. Core Application Intents</h4>

            
            <p>The Android upstream project defines a number of core applications, such as

            
            contacts, calendar, photo gallery, music player, and so on. Device implementers

            
            MAY replace these applications with alternative versions.</p>

            
            <p>However, any such alternative versions MUST honor the same Intent patterns

            
            provided by the upstream project. For example, if a device contains an

            
            alternative music player, it must still honor the Intent pattern issued by

            
            third-party applications to pick a song.</p>

            
            <p>The following applications are considered core Android system

            
            applications:</p>

            
            <ul>

            
            <li>Desk Clock</li>

            
            <li>Browser</li>

            
            <li>Calendar</li>

            
            <li>Contacts</li>

            
            <!--<li>Email</li>-->

            
            <li>Gallery</li>

            
            <li>GlobalSearch</li>

            
            <li>Launcher</li>

            
            <!-- <li>LivePicker (that is, the Live Wallpaper picker application; MAY be omitted

            
            if the device does not support Live Wallpapers, per Section 3.8.5.)</li> -->

            
            <!-- <li>Messaging (AKA "Mms")</li> -->

            
            <li>Music</li>

            
            <!-- <li>Phone</li> -->

            
            <li>Settings</li>

            
            <!-- <li>SoundRecorder</li> -->

            
            </ul>

            
            <p>The core Android system applications include various Activity, or Service

            
            components that are considered "public".  That is, the attribute

            
            "android:exported" may be absent, or may have the value "true".</p>

            
            <p>For every Activity or Service defined

            
            in one of the core Android system apps that is not marked as non-public via an

            
            android:exported attribute with the value "false", device implementations MUST

            
            include a compontent of the same type implementing the same Intent filter

            
            patterns as the core Android system app.</p>

            
            <p>In other words, a device implementation MAY replace core Android system

            
            apps; however, if it does, the device implementation MUST support all Intent

            
            patterns defined by each core Android system app being replaced.</p>

            
            <a name="section-3.2.3.2"></a><h4>3.2.3.2. Intent Overrides</h4>

            
            <p>As Android is an extensible platform, device implementations MUST allow each

            
            Intent pattern referenced in Section 3.2.3.2 to be overridden by third-party

            
            applications. The upstream Android open source implementation allows this by

            
            default; device implementers MUST NOT attach special privileges to system

            
            applications' use of these Intent patterns, or prevent third-party

            
            applications from binding to and assuming control of these patterns. This

            
            prohibition specifically includes but is not limited to disabling the

            
            "Chooser" user interface which allows the user to select between multiple

            
            applications which all handle the same Intent pattern.</p>

            
            <p>However, device implementations MAY provide default activities for specific

            
            URI patterns (eg. http://play.google.com) if the default activity provides a

            
            more specific filter for the data URI. For example, an intent filter specifying

            
            the data URI "http://www.android.com" is more specific than the browser filter

            
            for "http://". Device implementations MUST provide a user interface for users

            
            to modify the default activity for intents.</p>


            <a name="section-3.2.3.3"></a><h4>3.2.3.3. Intent Namespaces</h4>

            
            <p>Device implementations MUST NOT include any Android component that honors any

            
            new Intent or Broadcast Intent patterns using an ACTION, CATEGORY, or other

            
            key string in the android.* or com.android.* namespace. Device implementers

            
            MUST NOT include any Android components that honor any new Intent or Broadcast

            
            Intent patterns using an ACTION, CATEGORY, or other key string in a package

            
            space belonging to another organization. Device implementers MUST NOT alter or

            
            extend any of the Intent patterns used by the core apps listed in Section

            
            3.2.3.1. Device implementations MAY include Intent patterns using

            
            namespaces clearly and obviously associated with their own organization.</p>

            
            <p>This prohibition is analogous to that specified for Java language classes

            
            in Section 3.6.</p>

            
            <a name="section-3.2.3.4"></a><h4>3.2.3.4. Broadcast Intents</h4>

            
            <p>Third-party applications rely on the platform to broadcast certain Intents

            
            to notify them of changes in the hardware or software environment.

            
            Android-compatible devices MUST broadcast the public broadcast Intents in

            
            response to appropriate system events. Broadcast Intents are described in the

            
            SDK documentation.</p>


            <a name="section-3.3"></a><h3>3.3. Native API Compatibility</h3>

            
            <a name="section-3.3.1"></a><h4>3.3.1 Application Binary Interfaces</h4>

            
            <p>Managed code running in Dalvik can call into native code provided in the

            
            application .apk file as an ELF .so file compiled for the appropriate device

            
            hardware architecture. As native code is highly dependent on the underlying

            
            processor technology, Android defines a number of Application Binary

            
            Interfaces (ABIs) in the Android NDK, in the file

            
            <code>docs/CPU-ARCH-ABIS.html</code>. If a device implementation is compatible

            
            with one or more defined ABIs, it SHOULD implement compatibility with the

            
            Android NDK, as below.</p>

            
            <p>If a device implementation includes support for an Android ABI, it:</p>

            
            <ul>

            
            <li>MUST include support for code running in the managed environment to call

            
            into native code, using the standard Java Native Interface (JNI)

            
            semantics.</li>

            
            <li>MUST be source-compatible (i.e. header compatible) and binary-compatible

            
            (for the ABI) with each required library in the list below</li>

            
            <li>MUST accurately report the native Application Binary Interface (ABI)

            
            supported by the device, via the <code>android.os.Build.CPU_ABI</code>

            
            API</li>

            
            <li>MUST report only those ABIs documented in the latest version of the

            
            Android NDK, in the file <code>docs/CPU-ARCH-ABIS.txt</code></li>

            
            <li>SHOULD be built using the source code and header files available in the

            
            upstream Android open source project</li>

            
            </ul>

            
            <p>The following native code APIs MUST be available to apps that include

            
            native code:</p>

            
            <ul>

            
            <li>libc (C library)</li>

            
            <li>libm (math library)</li>

            
            <li>Minimal support for C++</li>

            
            <li>JNI interface</li>

            
            <li>liblog (Android logging)</li>

            
            <li>libz (Zlib compression)</li>

            
            <li>libdl (dynamic linker)</li>

            
            <li>libGLESv1_CM.so (OpenGL ES 1.0)</li>

            
            <li>libGLESv2.so (OpenGL ES 2.0)</li>

            
            <li>libEGL.so (native OpenGL surface management)</li>

            
            <li>libjnigraphics.so</li>

            
            <li>libOpenSLES.so (OpenSL ES 1.0.1 audio support)</li>

            
            <li>libOpenMAXAL.so (OpenMAX AL 1.0.1 support)</li>

            
            <li>libandroid.so (native Android activity support)</li>

            
            <li>Support for OpenGL, as described below</li>

            
            </ul>

            
            <p>Note that future releases of the Android NDK may introduce support for

            
            additional ABIs. If a device implementation is not compatible with an existing

            
            predefined ABI, it MUST NOT report support for any ABI at all.</p>

            
            <p>Native code compatibility is challenging. For this reason, it should be

            
            repeated that device implementers are VERY strongly encouraged to use the

            
            upstream implementations of the libraries listed above to help ensure

            
            compatibility.</p>


            <a name="section-3.4"></a><h3>3.4. Web Compatibility</h3>

            
            <a name="section-3.4.1"></a><h4>3.4.1. WebView Compatibility</h4>

            
            <p>The Android Open Source implementation uses the WebKit rendering engine to

            
            implement the <code>android.webkit.WebView</code>. Because it is not feasible

            
            to develop a comprehensive test suite for a web rendering system, device

            
            implementers MUST use the specific upstream build of WebKit in the WebView

            
            implementation.  Specifically:</p>

            
            <ul>

            
            <li>Device implementations' <code>android.webkit.WebView</code>

            
            implementations MUST be based on the 534.30 WebKit build from the upstream

            
            Android Open Source tree for Android 4.2. This build includes a specific set

            
            of functionality and security fixes for the WebView. Device implementers MAY

            
            include customizations to the WebKit implementation; however, any such

            
            customizations MUST NOT alter the behavior of the WebView, including rendering

            
            behavior.</li>

            
            <li>The user agent string reported by the WebView MUST be in this format:<br/>

            
                <code>Mozilla/5.0 (Linux; U; Android $(VERSION); $(LOCALE); $(MODEL) Build/$(BUILD)) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.2 Mobile Safari/534.30</code>

            
              <ul>

            
              <li>The value of the $(VERSION) string MUST be the same as the value for <code>android.os.Build.VERSION.RELEASE</code></li>

            
              <li>The value of the $(LOCALE) string SHOULD follow the ISO conventions for country code and language, and SHOULD refer to the current configured locale of the device</li>

            
              <li>The value of the $(MODEL) string MUST be the same as the value for <code>android.os.Build.MODEL</code></li>

            
              <li>The value of the $(BUILD) string MUST be the same as the value for <code>android.os.Build.ID</code></li>

            
              <li>Device implementations MAY omit <code>Mobile</code> in the user agent string</li>

            
              </ul>

            
            </li>

            
            </ul>

            
            <p>The WebView component SHOULD include support for as much of HTML5 [<a

            
            href="#resources11">Resources, 11</a>] as possible.

            
            Minimally, device implementations MUST support each of these APIs associated

            
            with HTML5 in the WebView:</p>

            
            <ul>

            
            <li>application cache/offline operation [<a href="#resources12">Resources, 12</a>]</li>

            
            <li>the &lt;video&gt; tag [<a href="#resources13">Resources, 13</a>]</li>

            
            <li>geolocation [<a href="#resources14">Resources, 14</a>]</li>

            
            </ul>

            
            <p>Additionally, device implementations MUST support the HTML5/W3C webstorage

            
            API [<a href="#resources15">Resources, 15</a>], and SHOULD support the

            
            HTML5/W3C IndexedDB API [<a href="#resources16">Resources, 16</a>]. <i>Note

            
            that as the web development standards bodies are transitioning to favor

            
            IndexedDB over webstorage, IndexedDB is expected to become a required

            
            component in a future version of Android.</i></p>

            
            <p>HTML5 APIs, like all JavaScript APIs, MUST be disabled by default in a

            
            WebView, unless the developer explicitly enables them via the usual Android

            
            APIs.</p>


            <a name="section-3.4.2"></a><h4>3.4.2. Browser Compatibility</h4>

            
            <p>Device implementations MUST include a standalone Browser application for

            
            general user web browsing. The standalone Browser MAY be based on a

            
            browser technology other than WebKit. However, even if an alternate Browser

            
            application is used, the <code>android.webkit.WebView</code> component

            
            provided to third-party applications MUST be based on WebKit, as described in

            
            Section 3.4.1.</p>

            
            <p>Implementations MAY ship a custom user agent string in the standalone

            
            Browser application.</p>

            
            <p>The standalone Browser application (whether based on the upstream

            
            WebKit Browser application or a third-party replacement) SHOULD include support

            
            for as much of HTML5 [<a href="#resources11">Resources, 11</a>] as possible.

            
            Minimally, device implementations MUST support each of these APIs associated

            
            with HTML5:</p>

            
            <ul>

            
            <li>application cache/offline operation [<a href="#resources12">Resources, 12</a>]</li>

            
            <li>the &lt;video&gt; tag [<a href="#resources13">Resources, 13</a>]</li>

            
            <li>geolocation [<a href="#resources14">Resources, 14</a>]</li>

            
            </ul>

            
            <p>Additionally, device implementations MUST support the HTML5/W3C webstorage

            
            API [<a href="#resources15">Resources, 15</a>], and SHOULD support the

            
            HTML5/W3C IndexedDB API [<a href="#resources16">Resources, 16</a>]. <i>Note

            
            that as the web development standards bodies are transitioning to favor

            
            IndexedDB over webstorage, IndexedDB is expected to become a required

            
            component in a future version of Android.</i></p>


            <a name="section-3.5"></a><h3>3.5. API Behavioral Compatibility</h3>

            
            <p>The behaviors of each of the API types (managed, soft, native, and web)

            
            must be consistent with the preferred implementation of the upstream Android

            
            open source project [<a href="#resources03">Resources, 3</a>]. Some specific areas

            
            of compatibility are:</p>

            
            <ul>

            
            <li>Devices MUST NOT change the behavior or semantics of a standard Intent</li>

            
            <li>Devices MUST NOT alter the lifecycle or lifecycle semantics of a

            
                particular type of system component (such as Service, Activity,

            
                ContentProvider, etc.)</li>

            
            <li>Devices MUST NOT change the semantics of a standard permission</li>

            
            </ul>

            
            <p>The above list is not comprehensive. The Compatibility Test Suite (CTS)

            
            tests significant portions of the platform for behavioral compatibility, but

            
            not all. It is the responsibility of the implementer to ensure behavioral

            
            compatibility with the Android Open Source Project.  For this reason, device

            
            implementers SHOULD use the source code available via the Android Open Source

            
            Project where possible, rather than re-implement significant parts of the

            
            system.</p>


            <a name="section-3.6"></a><h3>3.6. API Namespaces</h3>

            
            <p>Android follows the package and class namespace conventions defined by the

            
            Java programming language. To ensure compatibility with third-party

            
            applications, device implementers MUST NOT make any prohibited modifications

            
            (see below) to these package namespaces:</p>

            
            <ul>

            
            <li>java.*</li>

            
            <li>javax.*</li>

            
            <li>sun.*</li>

            
            <li>android.*</li>

            
            <li>com.android.*</li>

            
            </ul>

            
            <p>Prohibited modifications include:</p>

            
            <ul>

            
            <li>Device implementations MUST NOT modify the publicly exposed APIs on the

            
            Android platform by changing any method or class signatures, or by removing

            
            classes or class fields.</li>

            
            <li>Device implementers MAY modify the underlying implementation of the APIs,

            
            but such modifications MUST NOT impact the stated behavior and Java-language

            
            signature of any publicly exposed APIs.</li>

            
            <li>Device implementers MUST NOT add any publicly exposed elements (such as

            
            classes or interfaces, or fields or methods to existing classes or interfaces)

            
            to the APIs above.</li>

            
            </ul>

            
            <p>A "publicly exposed element" is any construct which is not decorated with

            
            the "@hide" marker as used in the upstream Android source code. In other

            
            words, device implementers MUST NOT expose new APIs or alter existing APIs in

            
            the namespaces noted above. Device implementers MAY make internal-only

            
            modifications, but those modifications MUST NOT be advertised or otherwise

            
            exposed to developers.</p>

            
            <p>Device implementers MAY add custom APIs, but any such APIs MUST NOT be in a

            
            namespace owned by or referring to another organization. For instance, device

            
            implementers MUST NOT add APIs to the com.google.* or similar namespace; only

            
            Google may do so. Similarly, Google MUST NOT add APIs to other companies'

            
            namespaces. Additionally, if a device implementation includes custom APIs

            
            outside the standard Android namespace, those APIs MUST be packaged in an

            
            Android shared library so that only apps that explicitly use them (via the

            
            <code>&lt;uses-library&gt;</code> mechanism) are affected by the increased

            
            memory usage of such APIs.</p>

            
            <p>If a device implementer proposes to improve one of the package namespaces

            
            above (such as by adding useful new functionality to an existing API, or

            
            adding a new API), the implementer SHOULD visit source.android.com and begin

            
            the process for contributing changes and code, according to the information on

            
            that site.</p>

            
            <p>Note that the restrictions above correspond to standard conventions for

            
            naming APIs in the Java programming language; this section simply aims to

            
            reinforce those conventions and make them binding through inclusion in this

            
            compatibility definition.</p>


            <a name="section-3.7"></a><h3>3.7. Virtual Machine Compatibility</h3>

            
            <p>Device implementations MUST support the full Dalvik Executable (DEX)

            
            bytecode specification and Dalvik Virtual Machine semantics [<a

            
            href="#resources17">Resources, 17</a>].</p>

            
            <p>Device implementations MUST configure Dalvik to allocate memory in

            
            accordance with the upstream Android platform, and as specified by the following

            
            table.  (See <a href="#section-7.1.1">Section 7.1.1</a> for screen size and screen

            
            density definitions.)</p>


            <p>Note that memory values specified below are considered minimum values,

            
            and device implementations MAY allocate more memory per application.</p>

            
            <table>

            
            <tbody>

            
            <tr>

            
            <td><b>Screen Size</b></td>

            
            <td><b>Screen Density</b></td>

            
            <td><b>Application Memory</b></td>

            
            </tr>

            
            <tr>

            
            <td>small / normal / large</td>

            
            <td>ldpi / mdpi</td>

            
            <td>16MB</td>

            
            </tr>

            
            <tr>

            
            <td>small / normal / large</td>

            
            <td>tvdpi / hdpi</td>

            
            <td>32MB</td>

            
            </tr>

            
            <tr>

            
            <td>small / normal / large</td>

            
            <td>xhdpi</td>

            
            <td>64MB</td>

            
            </tr>

            
            <tr>

            
            <td>xlarge</td>

            
            <td>mdpi</td>

            
            <td>32MB</td>

            
            </tr>

            
            <tr>

            
            <td>xlarge</td>

            
            <td>tvdpi / hdpi</td>

            
            <td>64MB</td>

            
            </tr>

            
            <tr>

            
            <td>xlarge</td>

            
            <td>xhdpi</td>

            
            <td>128MB</td>

            
            </tr>

            
            </tbody>

            
            </table>


            <a name="section-3.8"></a><h3>3.8. User Interface Compatibility</h3>

            
            <a name="section-3.8.1"></a><h4>3.8.1. Widgets</h4>

            
            <p>Android defines a component type and corresponding API and lifecycle that

            
            allows applications to expose an "AppWidget" to the end user [<a

            
            href="#resources18">Resources, 18</a>].

            
            The Android Open Source reference release includes a Launcher application that

            
            includes user interface affordances allowing the user to add, view, and remove

            
            AppWidgets from the home screen.</p>

            
            <p>Device implementations MAY substitute an alternative to the reference Launcher

            
            (i.e. home screen).  Alternative Launchers SHOULD include built-in support for

            
            AppWidgets, and expose user interface affordances to add, configure, view, and

            
            remove AppWidgets directly within the Launcher. Alternative Launchers MAY omit

            
            these user interface elements; however, if they are omitted, the device

            
            implementation MUST provide a separate application accessible from the Launcher

            
            that allows users to add, configure, view, and remove AppWidgets.</p>

            
            <p>Device implementations MUST be capable of rendering widgets that are 4 x 4

            
            in the standard grid size. (See the App Widget Design Guidelines in the Android

            
            SDK documentation [<a href="#resources18">Resources, 18</a>] for details.</p>

            
            <p>

            
            <a name="section-3.8.2"></a><h4>3.8.2. Notifications</h4>

            
            <p>Android includes APIs that allow developers to notify users of notable

            
            events [<a href="#resources19">Resources, 19</a>], using hardware and software

            
            features of the device.</p>

            
            <p>Some APIs allow applications to perform notifications or attract attention

            
            using hardware, specifically sound, vibration, and light. Device implementations

            
            MUST support notifications that use hardware features, as described in the SDK

            
            documentation, and to the extent possible with the device implementation

            
            hardware. For instance, if a device implementation includes a vibrator, it

            
            MUST correctly implement the vibration APIs. If a device implementation lacks

            
            hardware, the corresponding APIs MUST be implemented as no-ops. Note that this

            
            behavior is further detailed in <a href="#section-7">Section 7.</a></p>

            
            <p>Additionally, the implementation MUST correctly render all resources

            
            (icons, sound files, etc.) provided for in the APIs [<a

            
            href="#resources20">Resources, 20</a>], or in the

            
            Status/System Bar icon style guide [<a href="#resources21">Resources, 21</a>].

            
            Device implementers MAY provide an alternative user experience for

            
            notifications than that provided by the reference Android Open Source

            
            implementation; however, such alternative notification systems MUST support

            
            existing notification resources, as above.</p>

            
            <p>Android 4.2 includes support for rich notifications, such as interactive

            
            Views for ongoing notifications. Device implementations MUST properly display

            
            and execute rich notifications, as documented in the Android APIs.</p>

            
            <a name="section-3.8.3"></a><h4>3.8.3. Search</h4>

            
            <p>Android includes APIs [<a href="#resources22">Resources, 22</a>] that allow

            
            developers to incorporate search into their applications, and expose their

            
            application's data into the global system search. Generally speaking, this

            
            functionality consists of a single, system-wide user interface that allows users

            
            to enter queries, displays suggestions as users type, and displays results. The

            
            Android APIs allow developers to reuse this interface to provide search within

            
            their own apps, and allow developers to supply results to the common global

            
            search user interface.</p>

            
            <p>Device implementations MUST include a single, shared, system-wide search

            
            user interface capable of real-time suggestions in response to user input.

            
            Device implementations MUST implement the APIs that allow developers to reuse

            
            this user interface to provide search within their own applications. Device

            
            implementations MUST implement the APIs that allow third-party applications to

            
            add suggestions to the search box when it is run in global search mode. If no

            
            third-party applications are installed that make use of this functionality,

            
            the default behavior SHOULD be to display web search engine results and

            
            suggestions.</p>

            
            <a name="section-3.8.4"></a><h4>3.8.4. Toasts</h4>

            
            <p>Applications can use the "Toast" API (defined in [<a

            
            href="#resources23">Resources, 23</a>]) to

            
            display short non-modal strings to the end user, that disappear after a brief

            
            period of time. Device implementations MUST display Toasts from applications

            
            to end users in some high-visibility manner.</p>


            <a name="section-3.8.5"></a><h4>3.8.5. Themes</h4>

            
            <p>Android provides "themes" as a mechanism for applications to apply styles

            
            across an entire Activity or application. Android 4.2 includes a "Holo"

            
            or "holographic" theme as a set of defined styles for application developers to

            
            use if they want to match the Holo theme look and feel as defined by the Android

            
            SDK [<a href="#resources24">Resources, 24</a>]. Device implementations MUST NOT

            
            alter any of the Holo theme attributes exposed to applications

            
            [<a href="#resources25">Resources, 25</a>].</p>

            
            <p>Android 4.2 includes a new "Device Default" theme as a set of defined

            
            styles for application developers to use if they want to match the look and feel

            
            of the device theme as defined by the device implementer. Device implementations

            
            MAY modify the DeviceDefault theme attributes exposed to applications

            
            [<a href="#resources25">Resources, 25</a>].</p>


            <a name="section-3.8.6"></a><h4>3.8.6. Live Wallpapers</h4>

            
            <p>Android defines a component type and corresponding API and lifecycle that

            
            allows applications to expose one or more "Live Wallpapers" to the end user

            
            [<a href="#resources26">Resources, 26</a>]. Live Wallpapers are animations,

            
            patterns, or similar images with limited input capabilities that display as a

            
            wallpaper, behind other applications.</p>

            
            <p>Hardware is considered capable of reliably running live wallpapers if it

            
            can run all live wallpapers, with no limitations on functionality, at a

            
            reasonable framerate with no adverse affects on other applications. If

            
            limitations in the hardware cause wallpapers and/or applications to crash,

            
            malfunction, consume excessive CPU or battery power, or run at unacceptably

            
            low frame rates, the hardware is considered incapable of running live

            
            wallpaper. As an example, some live wallpapers may use an Open GL 1.0 or 2.0

            
            context to render their content. Live wallpaper will not run reliably on

            
            hardware that does not support multiple OpenGL contexts because the live

            
            wallpaper use of an OpenGL context may conflict with other applications that

            
            also use an OpenGL context.</p>

            
            <p>Device implementations capable of running live wallpapers reliably as

            
            described above SHOULD implement live wallpapers. Device implementations

            
            determined to not run live wallpapers reliably as described above MUST NOT

            
            implement live wallpapers.</p>

            
            <a name="section-3.8.7"></a><h4>3.8.7. Recent Application Display</h4>

            
            <p>The upstream Android 4.2 source code includes a user interface for

            
            displaying recent applications using a thumbnail image of the application's

            
            graphical state at the moment the user last left the application. Device

            
            implementations MAY alter or eliminate this user interface; however, a future

            
            version of Android is planned to make more extensive use of this

            
            functionality. Device implementations are strongly encouraged to use the

            
            upstream Android 4.2 user interface (or a similar thumbnail-based interface)

            
            for recent applications, or else they may not be compatible with a future

            
            version of Android.</p>

            
            <a name="section-3.8.8"></a><h4>3.8.8. Input Management Settings</h4>

            
            <p>Android 4.2 includes support for Input Management Engines. The Android 4.2

            
            APIs allow custom app IMEs to specify user-tunable settings. Device

            
            implementations MUST include a way for the user to access IME settings at all

            
            times when an IME that provides such user settings is displayed.</p>


            <a name="section-3.8.9"></a><h4>3.8.9. Lock and Home Screen Widgets</h4>

            
            <p>Android 4.2 includes support for application widgets that users can embed in the home screen or the lock screen

            
            (See the App Widget Design Guidelines in the Android SDK documentation [<a href="#resources69">Resources, 69</a>] for details).

            
            Application widgets allow quick access to application data and services without launching a new activity. Widgets declare support

            
            for usage on the home screen or the lock screen by declaring the <code>android:widgetCategory</code> manifest tag that tells the system

            
            where the widget can be placed. Specifically, device implementations MUST meet the following requirements.</p>

            
            <ul>

            
             <li>Device implementations MUST support application widgets on the home screen.</li>

            
             <li>Device implementations SHOULD support lock screen. If device implementations include support for lock screen

            
                 then device implementations MUST support application widgets on the lock screen.</li>

            
            </ul>


            <a name="section-3.8.10"></a><h4>3.8.10. Lock Screen Media Remote Control</h4>

            
            <p>Android 4.2 includes support for Remote Control API that lets media applications integrate with playback controls

            
            that are displayed in a remote view like the device lock screen[<a href="#resources74">Resources, 74</a>]. Device implementations MUST

            
            include support for embedding remote controls in the device lock screen.

            
            </p>

            
            <a name="section-3.8.11"></a><h4>3.8.11. Dreams</h4>

            
            <p>Android 4.2 includes support for interactive screensavers called Dreams [<a href="#resources76">Resources, 76</a>].

            
            Dreams allows users to interact with applications when a charging device is idle, or docked in a desk dock. Device implementations

            
            MUST include support for Dreams and provide a settings option for users to configure Dreams.</p>


            <a name="section-3.9"></a><h3>3.9 Device Administration</h3>

            
            <p>Android 4.2 includes features that allow security-aware applications

            
            to perform device administration functions at the system level, such as enforcing

            
            password policies or performing remote wipe, through the Android Device

            
            Administration API [<a href="#resources27">Resources, 27</a>]. Device

            
            implementations MUST provide an implementation of the <code>DevicePolicyManager

            
            </code> class [<a href="#resources28">Resources, 28</a>], and SHOULD support

            
            the full range of device administration policies defined in the Android SDK

            
            documentation [<a href="#resources27">Resources, 27</a>].

            
            </p>

            
            <p><b>Note:</b> while some of the requirements outlined above are stated as "SHOULD"

            
            for Android 4.2, device implementations that support lock screen MUST support device policies to manage widgets

            
            on the lock screen as defined in the Android SDK documentation [<a href="#resources27">Resources, 27</a>].

            
            </p>

            
            <p><b>Note:</b> while some of the requirements outlined above are stated as "SHOULD"

            
            for Android 4.2, the Compatibility Definition for a future version is planned

            
            to change these to "MUST". That is, these requirements are optional in Android

            
            4.2 but <b>will be required</b> by a future version. Existing and new devices

            
            that run Android 4.2 are <b>very strongly encouraged to meet

            
            these requirements in Android 4.2</b>, or they will not be able to attain

            
            Android compatibility when upgraded to the future version.</p>


            <a name="section-3.10"></a><h3>3.10 Accessibility</h3>

            
            <p>Android 4.2 provides an accessibility layer that helps users with disabilities

            
            to navigate their devices more easily. In addition, Android 4.2 provides

            
            platform APIs that enable accessibility service implementations to receive

            
            callbacks for user and system events and generate alternate feedback mechanisms,

            
            such as text-to-speech, haptic feedback, and trackball/d-pad navigation

            
            [<a href="#resources29">Resources, 29</a>]. Device implementations MUST provide an

            
            implementation of the Android accessibility framework consistent with the

            
            default Android implementation.  Specifically, device implementations MUST meet

            
            the following requirements.</p>

            
            <ul>

            
             <li>Device implementations MUST support third party accessibility service

            
                 implementations through the <code>android.accessibilityservice</code>

            
                 APIs [<a href="#resources30">Resources, 30</a>].</li>

            
             <li>Device implementations MUST generate <code>AccessibilityEvents</code>

            
                 and deliver these events to all registered <code>AccessibilityService

            
                 </code> implementations in a manner consistent with the default Android

            
                 implementation.</li>

            
             <li>Device implementations MUST provide a user-accessible mechanism to enable

            
                 and disable accessibility services, and MUST display this interface in

            
                 response to the

            
                 <code>android.provider.Settings.ACTION_ACCESSIBILITY_SETTINGS</code>

            
                 intent.</li>

            
            </ul>

            
            <p>Additionally, device implementations SHOULD provide an implementation

            
            of an accessibility service on the device, and SHOULD provide a mechanism

            
            for users to enable the accessibility service during device setup.  An open

            
            source implementation of an accessibility service is available from the Eyes

            
            Free project [<a href="#resources31">Resources, 31</a>].</p>


            <a name="section-3.11"></a><h3>3.11 Text-to-Speech</h3>

            
            <p>Android 4.2 includes APIs that allow applications to make use of

            
            text-to-speech (TTS) services, and allows service providers to provide

            
            implementations of TTS services [<a href="#resources32">Resources, 32</a>].

            
            Device implementations MUST meet these requirements related to the Android TTS

            
            framework:</p>

            
            <ul>

            
              <li>Device implementations MUST support the Android TTS framework APIs and

            
                  SHOULD include a TTS engine supporting the languages available on the

            
                  device. Note that the upstream Android open source software includes a

            
                  full-featured TTS engine implementation.</li>

            
              <li>Device implementations MUST support installation of third-party TTS

            
                  engines.</li>

            
              <li>Device implementations MUST provide a user-accessible interface that allows

            
                  users to select a TTS engine for use at the system level.</li>

            
            </ul>


            <a name="section-4"></a><h2>4. Application Packaging Compatibility</h2>

            
            <p>Device implementations MUST install and run Android ".apk" files as

            
            generated by the "aapt" tool included in the official Android SDK [<a

            
            href="#resources33">Resources, 33</a>].</p>

            
            <p>Devices implementations MUST NOT extend either the .apk [<a

            
            href="#resources34">Resources, 34</a>], Android Manifest [<a

            
            href="#resources35">Resources, 35</a>],

            
            Dalvik bytecode [<a href="#resources17">Resources, 17</a>], or renderscript

            
            bytecode formats in such a way that would prevent those files from installing

            
            and running correctly on other compatible devices. Device implementers SHOULD

            
            use the reference upstream implementation of Dalvik, and the reference

            
            implementation's package management system.</p>


            <a name="section-5"></a><h2>5. Multimedia Compatibility</h2>

            
            <p>Device implementations MUST include at least one form of audio output, such as

            
            speakers, headphone jack, external speaker connection, etc.</p>

            
            <a name="section-5.1"></a><h3>5.1. Media Codecs</h3>

            
            <p>Device implementations MUST support the core media formats specified

            
            in the Android SDK documentation [<a href="#resources58">Resources, 58</a>] except

            
            where explicitly permitted in this document. Specifically, device implementations

            
            MUST support the media formats, encoders, decoders, file types and container

            
            formats defined in the tables below. All of these codecs are provided as

            
            software implementations in the preferred Android implementation from the Android

            
            Open Source Project.</p>


            <p><strong>Please note that neither Google nor the Open Handset Alliance make any

            
            representation that these codecs are unencumbered by third-party patents.

            
            Those intending to use this source code in hardware or software products are

            
            advised that implementations of this code, including in open source software

            
            or shareware, may require patent licenses from the relevant patent

            
            holders.</strong></p>


            <p>Note that these tables do not list specific bitrate requirements for

            
            most video codecs because current device hardware does not necessarily support

            
            bitrates that map exactly to the required bitrates specified by the relevant

            
            standards. Instead, device implementations SHOULD support the highest bitrate

            
            practical on the hardware, up to the limits defined by the specifications.</p>

            
            <div style="page-break-before: always;"></div>

            
            <table>

            
            <tbody>


            <tr>

            
            <th>Type</th>

            
            <th>Format / Codec</th>

            
            <th>Encoder</th>

            
            <th>Decoder</th>

            
            <th>Details</th>

            
            <th>File Type(s) / Container Formats</th>

            
            </tr>


            <tr>

            
            <td rowspan="11">Audio</td>

            
            <td>MPEG-4 AAC Profile (AAC LC)</td>

            
            <td style="text-align: center;">REQUIRED<br/>

            
            <small>Required for device implementations that include microphone hardware

            
            and define <code>android.hardware.microphone</code>.</small></td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td rowspan="1"> Support for mono/stereo/5.0/5.1* content with standard sampling rates from 8 to 48 kHz.</td>

            
            <td rowspan="4">

            
              <ul>

            
                <li>3GPP (.3gp)</li>

            
                <li>MPEG-4 (.mp4, .m4a)</li>

            
                <li>ADTS raw AAC (.aac, decode in Android 3.1+, encode in Android 4.0+, ADIF not supported)</li>

            
                <li>MPEG-TS (.ts, not seekable, Android 3.0+)</li>

            
              </ul>

            
            </td>

            
            </tr>


            <tr>

            
            <td>MPEG-4 HE AAC Profile (AAC+)</td>

            
            <td>REQUIRED for device implementations that include microphone hardware and define android.hardware.microphone</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>Support for mono/stereo/5.0/5.1* content with standard sampling rates from 16 to 48 kHz.</td>

            
            </tr>


            <tr>

            
            <td>MPEG-4 HE AAC v2 Profile (enhanced AAC+)</td>

            
            <td>&nbsp;</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>Support for mono/stereo/5.0/5.1* content with standard sampling rates from 16 to 48 kHz.</td>

            
            </tr>


            <tr>

            
            <td>MPEG-4 Audio Object Type ER AAC ELD (Enhanced Low Delay AAC)</td>

            
            <td>REQUIRED for device implementations that include microphone hardware and define android.hardware.microphone</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>Support for mono/stereo content with standard

            
            sampling rates from 16 to 48 kHz.</td>

            
            </tr>


            <tr>

            
            <td>AMR-NB</td>

            
            <td style="text-align: center;">REQUIRED<br/>

            
            <small>Required for device implementations that include microphone hardware

            
            and define <code>android.hardware.microphone</code>.</small></td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>4.75 to 12.2 kbps sampled @ 8kHz</td>

            
            <td>3GPP (.3gp)

            
            </td>

            
            </tr>


            <tr>

            
            <td>AMR-WB</td>

            
            <td style="text-align: center;">REQUIRED<br/>

            
            <small>Required for device implementations that include microphone hardware

            
            and define <code>android.hardware.microphone</code>.</small></td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16kHz</td>

            
            <td>3GPP (.3gp)</td>

            
            </tr>


            <tr>

            
            <td>FLAC</td>

            
            <td>&nbsp;</td>

            
            <td style="text-align: center;">REQUIRED<br/><small>(Android 3.1+)</small></td>

            
            <td>Mono/Stereo (no multichannel). Sample rates up to 48 kHz (but up to 44.1

            
            kHz is recommended on devices with 44.1 kHz output, as the 48 to 44.1 kHz

            
            downsampler does not include a low-pass filter). 16-bit recommended;

            
            no dither applied for 24-bit.

            
            </td>

            
            <td>FLAC (.flac) only</td>

            
            </tr>


            <tr>

            
            <td>MP3</td>

            
            <td>&nbsp;</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>Mono/Stereo 8-320Kbps constant (CBR) or variable bit-rate (VBR)

            
            </td>

            
            <td>MP3 (.mp3)</td>

            
            </tr>


            <tr>

            
            <td>MIDI</td>

            
            <td>&nbsp;</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>MIDI Type 0 and 1. DLS Version 1 and 2. XMF and Mobile XMF. Support for ringtone formats RTTTL/RTX, OTA, and iMelody </td>

            
            <td>

            
              <ul>

            
                <li>Type 0 and 1 (.mid, .xmf, .mxmf)</li>

            
                <li>RTTTL/RTX (.rtttl, .rtx)</li>

            
                <li>OTA (.ota)</li>

            
                <li>iMelody (.imy)</li>

            
              </ul>

            
            </td>

            
            </tr>


            <tr>

            
            <td>Vorbis</td>

            
            <td>&nbsp;</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>&nbsp;</td>

            
            <td>

            
              <ul>

            
                <li>Ogg (.ogg)</li>

            
                <li>Matroska (.mkv)</li>

            
              </ul>

            
            </td>

            
            </tr>


            <tr>

            
            <td>PCM/WAVE</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>8-bit and 16-bit linear PCM** (rates up to limit of hardware).Devices MUST support sampling rates

            
            for raw PCM recording at 8000,16000 and 44100 Hz frequencies</td>

            
            <td>WAVE (.wav)</td>

            
            </tr>


            <tr>

            
            <td rowspan="5">Image</td>

            
            <td>JPEG</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>Base+progressive</td>

            
            <td>JPEG (.jpg)</td>

            
            </tr>


            <tr>

            
            <td>GIF</td>

            
            <td>&nbsp;</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>&nbsp;</td>

            
            <td>GIF (.gif)</td>

            
            </tr>


            <tr>

            
            <td>PNG</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>&nbsp;</td>

            
            <td>PNG (.png)</td>

            
            </tr>


            <tr>

            
            <td>BMP</td>

            
            <td>&nbsp;</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>&nbsp;</td>

            
            <td>BMP (.bmp)</td>

            
            </tr>


            <tr>

            
            <td>WEBP</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>&nbsp;</td>

            
            <td>WebP (.webp)</td>

            
            </tr>


            <tr>

            
            <td rowspan="4">Video</td>

            
            <td>H.263</td>

            
            <td style="text-align: center;">REQUIRED<br/>

            
            <small>Required for device implementations that include camera hardware

            
            and define <code>android.hardware.camera</code> or

            
            <code>android.hardware.camera.front</code>.</small></td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>&nbsp;</td>

            
            <td>

            
              <ul>

            
                <li>3GPP (.3gp)</li>

            
                <li>MPEG-4 (.mp4)</li>

            
              </ul>

            
            </td>

            
            </tr>


            <tr>

            
            <td>H.264 AVC</td>

            
            <td style="text-align: center;">REQUIRED<br/>

            
            <small>Required for device implementations that include camera hardware

            
            and define <code>android.hardware.camera</code> or

            
            <code>android.hardware.camera.front</code>.</small></td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>Baseline Profile (BP)</td>

            
            <td>

            
              <ul>

            
                <li>3GPP (.3gp)</li>

            
                <li>MPEG-4 (.mp4)</li>

            
                <li>MPEG-TS (.ts, AAC audio only, not seekable, Android 3.0+)</li>

            
              </ul>

            
            </td>

            
            </tr>


            <tr>

            
            <td>MPEG-4 SP</td>

            
            <td>&nbsp;</td>

            
            <td style="text-align: center;">REQUIRED</td>

            
            <td>&nbsp;</td>

            
            <td>3GPP (.3gp)</td>

            
            </tr>


            <tr>

            
            <td>VP8</td>

            
            <td>&nbsp;</td>

            
            <td style="text-align: center;">REQUIRED<br/><small>(Android 2.3.3+)</small></td>

            
            <td>&nbsp;</td>

            
            <td><a href="http://www.webmproject.org/">WebM</a> (.webm) and Matroska (.mkv, Android 4.0+)</td>

            
            </tr>


            </tbody></table>

            
            *Note: Only downmix of 5.0/5.1 content is required; recording or rendering more than 2 channels is optional.

            
            **Note: 16-bit linear PCM capture is mandatory. 8-bit linear PCM capture is not mandatory.


            <a name="section-5.2"></a><h3>5.2 Video Encoding</h3>

            
            <p>Android device implementations that include a rear-facing camera and declare

            
            <code>android.hardware.camera</code> SHOULD support the following video encoding

            
            profiles.</p>

            
            <table>

            
              <thead>

            
              <tr>

            
                <th>&nbsp;</th>

            
                <th>SD (Low quality)</th>

            
                <th>SD (High quality)</th>

            
                <th>HD (When supported by hardware)</th>

            
              </tr>

            
              </thead>

            
              <tbody>

            
              <tr>

            
                <th>Video codec</th>

            
                <td>H.264 Baseline Profile</td>

            
                <td>H.264 Baseline Profile</td>

            
                <td>H.264 Baseline Profile</td>

            
              </tr>

            
              <tr>

            
                <th>Video resolution</th>

            
                <td>176 x 144 px</td>

            
                <td>480 x 360 px</td>

            
                <td>1280 x 720 px</td>

            
              </tr>

            
              <tr>

            
                <th>Video frame rate</th>

            
                <td>12 fps</td>

            
                <td>30 fps</td>

            
                <td>30 fps</td>

            
              </tr>

            
              <tr>

            
                <th>Video bitrate</th>

            
                <td>56 Kbps</td>

            
                <td>500 Kbps or higher</td>

            
                <td>2 Mbps or higher</td>

            
              </tr>

            
              <tr>

            
                <th>Audio codec</th>

            
                <td>AAC-LC</td>

            
                <td>AAC-LC</td>

            
                <td>AAC-LC</td>

            
              </tr>

            
              <tr>

            
                <th>Audio channels</th>

            
                <td>1 (mono)</td>

            
                <td>2 (stereo)</td>

            
                <td>2 (stereo)</td>

            
              </tr>

            
              <tr>

            
                <th>Audio bitrate</th>

            
                <td>24 Kbps</td>

            
                <td>128 Kbps</td>

            
                <td>192 Kbps</td>

            
              </tr>

            
              </tbody>

            
            </table>


            <a name="section-5.3"></a><h3>5.3 Video Decoding</h3>

            
            <p>Android device implementations SHOULD support the following VP8 video decoding profiles.</p>

            
            <div style="page-break-before: always;"></div>

            
            <table>

            
              <thead>

            
              <tr>

            
                <th>&nbsp;</th>

            
                <th>SD (Low quality)</th>

            
                <th>SD (High quality)</th>

            
                <th>HD 720p <br/> (When supported by hardware)</th>

            
                <th>HD 1080p <br/>(When supported by hardware)</th>

            
              </tr>

            
              </thead>

            
              <tbody>

            
              <tr>

            
                <th>Video resolution</th>

            
                <td>320 x 180 px</td>

            
                <td>640 x 360 px</td>

            
                <td>1280 x 720 px</td>

            
                <td>1920 x 1080 px</td>

            
              </tr>

            
              <tr>

            
                <th>Video frame rate</th>

            
                <td>30 fps</td>

            
                <td>30 fps</td>

            
                <td>30 fps</td>

            
                <td>30 fps</td>

            
              </tr>

            
              <tr>

            
                <th>Video bitrate</th>

            
                <td>800 Kbps</td>

            
                <td>2 Mbps</td>

            
                <td>8 Mbps</td>

            
                <td>20 Mbps</td>

            
              </tr>

            
              </tbody>

            
            </table>

            
            <a name="section-5.4"></a><h3>5.4. Audio Recording</h3>

            
            <p>When an application has used the <code>android.media.AudioRecord</code> API to

            
            start recording an audio stream, device implementations that include microphone

            
            hardware and declare <code>android.hardware.microphone</code> MUST sample and

            
            record audio with each of these behaviors:</p>

            
            <ul>

            
            <li>The device SHOULD exhibit approximately flat amplitude versus frequency

            
                characteristics; specifically, &plusmn;3 dB, from 100 Hz to 4000 Hz</li>

            
            <li>Audio input sensitivity SHOULD be set such that a 90 dB sound power level

            
                (SPL) source at 1000 Hz yields RMS of 2500 for 16-bit samples.</li>

            
            <li>PCM amplitude levels SHOULD linearly track input SPL changes over at least

            
                a 30 dB range from -18 dB to +12 dB re 90 dB SPL at the microphone.</li>

            
            <li>Total harmonic distortion SHOULD be less than 1% for 1Khz at 90 dB SPL input level.</li>

            
            </ul>

            
            <p>In addition to the above recording specifications, when an application has

            
            started recording an audio stream using the

            
            <code>android.media.MediaRecorder.AudioSource.VOICE_RECOGNITION</code> audio

            
            source:</p>

            
            <ul>

            
            <li>Noise reduction processing, if present, MUST be disabled.</li>

            
            <li>Automatic gain control, if present, MUST be disabled.</li>

            
            </ul>

            
            <p><b>Note:</b> while some of the requirements outlined above are stated as "SHOULD"

            
            for Android 4.2, the Compatibility Definition for a future version is planned

            
            to change these to "MUST". That is, these requirements are optional in Android

            
            4.2 but <b>will be required</b> by a future version. Existing and new devices

            
            that run Android 4.2 are <b>very strongly encouraged to meet

            
            these requirements in Android 4.2</b>, or they will not be able to attain

            
            Android compatibility when upgraded to the future version.</p>


            <a name="section-5.5"></a><h3>5.5. Audio Latency</h3>

            
            <p>Audio latency is the time delay as an audio signal passes through a system.

            
            Many classes of

            
            applications rely on short latencies, to achieve real-time effects such sound

            
            effects or VOIP communication.</p>

            
            <p>For the purposes of this section:</p>

            
            <ul>

            
            <li>"output latency" is defined as the interval between when an application

            
            writes a frame of PCM-coded data and when the corresponding sound can be heard

            
            by an external listener or observed by a transducer</li>

            
            <li>"cold output latency" is defined as the output latency for the first frame, when

            
                the audio output system has been idle and powered down prior to the request</li>

            
            <li>"continuous output latency" is defined as the output latency for subsequent frames,

            
                after the device is already playing audio</li>

            
            <li>"input latency" is the interval between when an external sound is presented

            
            to the device and when an application reads the corresponding frame of PCM-coded data</li>

            
            <li>"cold input latency" is defined as the sum of lost input time

            
                and the input latency for the first frame, when

            
                the audio input system has been idle and powered down prior to the request</li>

            
            <li>"continuous input latency" is defined as the input latency for subsequent frames,

            
                while the device is already capturing audio</li>

            
            <li>"OpenSL ES PCM buffer queue API" is the set of PCM-related OpenSL ES APIs within Android NDK;

            
            see <i>NDK_root</i><code>/docs/opensles/index.html</code></li>

            
            </ul>

            
            <p>Per <a href="#section-5">Section 5</a>,

            
            all compatible device implementations MUST include at least one form of audio output.

            
            Device implementations SHOULD meet or exceed these output latency requirements:</p>

            
            <ul>

            
            <li>cold output latency of 100 milliseconds or less</li>

            
            <li>continuous output latency of 45 milliseconds or less</li>

            
            </ul>

            
            <p>If a device implementation meets the requirements of this section

            
            after any initial calibration

            
            when using the OpenSL ES PCM buffer queue API,

            
            for continuous output latency and cold output latency

            
            over at least one supported audio output device, it MAY

            
            report support for low-latency audio, by reporting the feature

            
            "android.hardware.audio.low-latency" via the

            
            <code>android.content.pm.PackageManager</code> class. [<a

            
            href="#resources37">Resources, 37</a>] Conversely, if the device

            
            implementation does not meet these requirements it MUST NOT report support for

            
            low-latency audio.</p>

            
            <p>

            
            Per <a href="#section-7.2.5">Section 7.2.5</a>,

            
            microphone hardware may be omitted by device implementations.</p>

            
            <p>

            
            Device implementations that include microphone

            
            hardware and declare <code>android.hardware.microphone</code> SHOULD

            
            meet these input audio latency requirements:</p>

            
            <ul>

            
            <li>cold input latency of 100 milliseconds or less</li>

            
            <li>continuous input latency of 50 milliseconds or less</li>

            
            </ul>


            <a name="section-5.6"></a><h3>5.6. Network Protocols</h3>

            
            <p>Devices MUST support the media network protocols for audio and video playback

            
            as specified in the Android SDK documentation

            
            [<a href="#resources58">Resources, 58</a>].  Specifically, devices MUST support

            
            the following media network protocols:</p>

            
            <ul>

            
            <li>RTSP (RTP, SDP)</li>

            
            <li>HTTP(S) progressive streaming</li>

            
            <li>HTTP(S) Live Streaming draft protocol, Version 3 [<a href="#resources59">Resources, 59</a>]</li>

            
            </ul>

            
            <a name="section-6"></a><h2>6. Developer Tools and Options Compatibility</h2>


            <a name="section-6.1"></a><h3>6.1 Developer Tools</h3>

            
            <p>Device implementations MUST support the Android Developer Tools provided in the Android SDK.

            
            Specifically, Android-compatible devices MUST be compatible with:</p>

            
            <ul>

            
            <li><b>Android Debug Bridge (known as adb)</b> [<a href="#resources33">Resources, 33</a>]<br/>

            
            Device implementations MUST support all <code>adb</code> functions as

            
            documented in the Android SDK. The device-side <code>adb</code> daemon MUST

            
            be inactive by default, and there MUST be a user-accessible mechanism to turn

            
            on the Android Debug Bridge.</li>

            
            <p>Android 4.2.2 includes support for secure adb. Secure adb enables adb on known authenticated hosts.

            
            Existing and new devices that run Android 4.2.2 are <b>very strongly encouraged to meet

            
            this requirement in Android 4.2</b>, or they will not be able to attain

            
            Android compatibility when upgraded to the future version.</p>

            
            <li><b>Dalvik Debug Monitor Service (known as ddms)</b> [<a href="#resources33">Resources, 33</a>]<br/>

            
            Device implementations MUST support all <code>ddms</code> features as documented in the

            
            Android SDK. As <code>ddms</code> uses <code>adb</code>, support for

            
            <code>ddms</code> SHOULD be inactive by default,

            
            but MUST be supported whenever the user has activated the Android Debug

            
            Bridge, as above.</li>

            
            <li><b>Monkey</b> [<a href="#resources36">Resources, 36</a>]<br/>

            
            Device implementations MUST include the Monkey framework, and make it

            
            available for applications to use.</li>

            
            <li><b>SysTrace</b> [<a href="#resources33">Resources, 33</a>]<br/>

            
            Device implementations MUST support systrace tool as documented in the Android SDK.

            
            Systrace must be inactive by default, and there MUST be a user-accessible mechanism to turn

            
            on Systrace.</li>

            
            </ul>

            
            <p>Most Linux-based systems and Apple Macintosh systems recognize Android

            
            devices using the standard Android SDK tools, without additional support;

            
            however Microsoft Windows systems typically require a driver for new Android

            
            devices. (For instance, new vendor IDs and sometimes new device IDs require

            
            custom USB drivers for Windows systems.) If a device implementation is

            
            unrecognized by the <code>adb</code> tool as provided in the standard Android

            
            SDK, device implementers MUST provide Windows drivers allowing developers to

            
            connect to the device using the <code>adb</code> protocol. These drivers MUST

            
            be provided for Windows XP, Windows Vista, Windows 7, and Windows 8, in both 32-bit and

            
            64-bit versions.</p>


            <a name="section-6.2"></a><h3>6.2 Developer Options</h3>

            
            <p>Android 4.2 includes support for developers to configure application development-related settings.

            
            Device implementations MUST honor the android.settings.APPLICATION_DEVELOPMENT_SETTINGS intent to show

            
            application development-related settings [<a href="#resources77">Resources, 77</a>]. The upstream Android

            
            implementation hides the Developer Options menu by default, and enables users to launch Developer Options

            
            after pressing seven (7) times on the Settings > About Device > Build Number menu item. Device implementations

            
            MUST provide a consistent experience for Developer Options. Specifically, device implementations MUST hide

            
            Developer Options by default and MUST provide a mechanism to enable Developer Options that is consistent with

            
            the upstream Android implementation.</p>


            <a name="section-7"></a><h2>7. Hardware Compatibility</h2>

            
            <p>If a device includes a particular hardware component that has a

            
            corresponding API for third-party developers, the device implementation MUST

            
            implement that API as described in the Android SDK documentation. If an API in

            
            the SDK interacts with a hardware component that is stated to be optional and

            
            the device implementation does not possess that component:</p>

            
            <ul>

            
            <li>complete class definitions (as documented by the SDK) for the component's

            
            APIs MUST still be present</li>

            
            <li>the API's behaviors MUST be implemented as no-ops in some reasonable

            
            fashion</li>

            
            <li>API methods MUST return null values where permitted by the SDK

            
            documentation</li>

            
            <li>API methods MUST return no-op implementations of classes where null

            
            values are not permitted by the SDK documentation</li>

            
            <li>API methods MUST NOT throw exceptions not documented by the SDK

            
            documentation</li>

            
            </ul>

            
            <p>A typical example of a scenario where these requirements apply is the

            
            telephony API: even on non-phone devices, these APIs must be implemented as

            
            reasonable no-ops.</p>

            
            <p>Device implementations MUST accurately report accurate hardware configuration

            
            information via the <code>getSystemAvailableFeatures()</code> and

            
            <code>hasSystemFeature(String)</code> methods on the

            
            <code>android.content.pm.PackageManager</code> class. [<a

            
            href="#resources37">Resources, 37</a>]</p>


            <a name="section-7.1"></a><h3>7.1. Display and Graphics</h3>

            
            <p>Android 4.2 includes facilities that automatically adjust application

            
            assets and UI layouts appropriately for the device, to ensure that third-party

            
            applications run well on a variety of hardware configurations [<a

            
            href="#resources38">Resources, 38</a>]. Devices MUST properly implement these

            
            APIs and behaviors, as detailed in this section.</p>


            <p>The units referenced by the requirements in this section are defined as follows:</p>

            
            <ul>

            
            <li>"Physical diagonal size" is the distance in inches between two opposing

            
            corners of the illuminated portion of the display.</li>

            
            <li>"dpi" (meaning "dots per inch") is the number of pixels encompassed by a

            
            linear horizontal or vertical span of 1". Where dpi values are listed, both

            
            horizontal and vertical dpi must fall within the range.</li>

            
            <li>"Aspect ratio" is the ratio of the longer dimension of the screen to the

            
            shorter dimension. For example, a display of 480x854 pixels would be 854 / 480

            
            = 1.779, or roughly "16:9".</li>

            
            <li>A "density-independent pixel" or ("dp") is the virtual pixel unit normalized to a

            
            160 dpi screen, calculated as:

            
            <code>pixels = dps * (density / 160)</code>.</li>

            
            </ul>


            <a name="section-7.1.1"></a><h4>7.1.1. Screen Configuration</h4>


            <p style="font-weight:bold;">Screen Size</p>

            
            <p>The Android UI framework supports a variety of different screen sizes, and

            
            allows applications to query the device screen size (aka "screen layout") via

            
            <code>android.content.res.Configuration.screenLayout</code> with the

            
            <code>SCREENLAYOUT_SIZE_MASK</code>. Device implementations MUST report the

            
            correct screen size as defined in the Android SDK documentation

            
            [<a href="#resources38">Resources, 38</a>] and determined by the upstream

            
            Android platform. Specifically, device implementations must report the correct

            
            screen size according to the following logical density-independent pixel (dp)

            
            screen dimensions.</p>

            
            <ul>

            
            <li>Devices MUST have screen sizes of at least 426 dp x 320 dp ('small')</li>

            
            <li>Devices that report screen size 'normal' MUST have screen sizes of at least

            
            480 dp x 320 dp</li>

            
            <li>Devices that report screen size 'large' MUST have screen sizes of at least

            
            640 dp x 480 dp</li>

            
            <li>Devices that report screen size 'xlarge' MUST have screen sizes of at least

            
            960 dp x 720 dp</li>

            
            </ul>

            
            <p>In addition, devices MUST have screen sizes of at least 2.5 inches in

            
            physical diagonal size.</p>


            <p>Devices MUST NOT change their reported screen size at any time.</p>

            
            <p>Applications optionally indicate which screen sizes they support via the

            
            <code>&lt;supports-screens&gt;</code> attribute in the AndroidManifest.xml

            
            file. Device implementations MUST correctly honor applications' stated support

            
            for small, normal, large, and xlarge screens, as described in the Android

            
            SDK documentation.</p>


            <p style="font-weight:bold;">Screen Aspect Ratio</p>

            
            <p>The aspect ratio MUST be between 1.3333 (4:3) and 1.85 (16:9).</p>


            <p style="font-weight:bold;">Screen Density</p>

            
            <p>The Android UI framework defines a set of standard logical densities to

            
            help application developers target application resources. Device

            
            implementations MUST report one of the following logical Android framework

            
            densities through the <code>android.util.DisplayMetrics</code> APIs, and MUST

            
            execute applications at this standard density.

            
            <ul>

            
            <li>120 dpi, known as 'ldpi'</li>

            
            <li>160 dpi, known as 'mdpi'</li>

            
            <li>213 dpi, known as 'tvdpi'</li>

            
            <li>240 dpi, known as 'hdpi'</li>

            
            <li>320 dpi, known as 'xhdpi'</li>

            
            <li>480 dpi, known as 'xxhdpi'</li>

            
            </ul>

            
            Device implementations SHOULD define the standard Android framework density

            
            that is numerically closest to the physical density of the screen, unless that

            
            logical density pushes the reported screen size below the minimum supported.

            
            If the standard Android framework density that is numerically closest to the

            
            physical density results in a screen size that is smaller than the smallest

            
            supported compatible screen size (320 dp width), device implementations SHOULD

            
            report the next lowest standard Android framework density.</p>


            <a name="section-7.1.2"></a><h4>7.1.2. Display Metrics</h4>

            
            <p>Device implementations MUST report correct values for all display metrics

            
            defined in <code>android.util.DisplayMetrics</code> [<a

            
            href="#resources39">Resources, 39</a>].</p>


            <a name="section-7.1.3"></a><h4>7.1.3. Screen Orientation</h4>

            
            <p>Devices MUST support dynamic orientation by applications to

            
            either portrait or landscape screen orientation. That is, the device must

            
            respect the application's request for a specific screen orientation. Device

            
            implementations MAY select either portrait or landscape orientation as the

            
            default.</p>

            
            <p>Devices MUST report the correct value for the device's current orientation,

            
            whenever queried via the android.content.res.Configuration.orientation,

            
            android.view.Display.getOrientation(), or other APIs.</p>

            
            <p>Devices MUST NOT change the reported screen size or density when changing

            
            orientation.</p>

            
            <p>Devices MUST report which screen orientations they support (

            
            <code>android.hardware.screen.portrait</code> and/or

            
            <code>android.hardware.screen.landscape</code>) and MUST report at least one

            
            supported orientation.  For example, a device with a fixed-orientation

            
            landscape screen, such as a television or laptop, MUST only report

            
            <code>android.hardware.screen.landscape</code>.</p>


            <a name="section-7.1.4"></a><h4>7.1.4. 2D and 3D Graphics Acceleration</h4>

            
            <p>Device implementations MUST support both OpenGL ES 1.0 and 2.0, as embodied

            
            and detailed in the Android SDK documentations. Device implementations MUST

            
            also support Android Renderscript, as detailed in the Android SDK

            
            documentation [<a href="#resources08">Resources, 8</a>].</p>

            
            <p>Device implementations MUST also correctly identify themselves as

            
            supporting OpenGL ES 1.0 and 2.0. That is:</p>

            
            <ul>

            
            <li>The managed APIs (such as via the <code>GLES10.getString()</code> method)

            
            MUST report support for OpenGL ES 1.0 and 2.0</li>

            
            <li>The native C/C++ OpenGL APIs (that is, those available to apps via

            
            libGLES_v1CM.so, libGLES_v2.so, or libEGL.so) MUST report support for

            
            OpenGL ES 1.0 and 2.0.</li>

            
            </ul>

            
            <p>Device implementations MAY implement any desired OpenGL ES extensions.

            
            However, device implementations MUST report via the OpenGL ES managed and

            
            native APIs all extension strings that they do support, and conversely MUST

            
            NOT report extension strings that they do not support.</p>

            
            <p>Note that Android 4.2 includes support for applications to optionally

            
            specify that they require specific OpenGL texture compression formats. These

            
            formats are typically vendor-specific. Device implementations are not required

            
            by Android 4.2 to implement any specific texture compression format. However,

            
            they SHOULD accurately report any texture compression formats that they do

            
            support, via the <code>getString()</code> method in the OpenGL API.</p>


            <p>Android 4.2 includes a mechanism for applications to declare that they

            
            wanted to enable hardware acceleration for 2D graphics at the Application,

            
            Activity, Window or View level through the use of a manifest tag

            
            <code>android:hardwareAccelerated</code> or direct API calls

            
            [<a href="#resources09">Resources, 9</a>].</p>

            
            <p>In Android 4.2, device implementations MUST enable hardware acceleration by

            
            default, and MUST disable hardware acceleration if the developer so requests

            
            by setting <code>android:hardwareAccelerated="false"</code> or disabling

            
            hardware acceleration directly through the Android View APIs.</p>

            
            <p>In addition, device implementations MUST exhibit behavior consistent with the

            
            Android SDK documentation on hardware acceleration

            
            [<a href="#resources09">Resources, 9</a>].</p>

            
            <p>Android 4.2 includes a <code>TextureView</code> object that lets developers

            
            directly integrate hardware-accelerated OpenGL ES textures as rendering targets

            
            in a UI hierarchy. Device implementations MUST support the <code>TextureView

            
            </code> API, and MUST exhibit consistent behavior with the upstream Android

            
            implementation.</p>


            <a name="section-7.1.5"></a><h4>7.1.5. Legacy Application Compatibility Mode</h4>

            
            <p>Android 4.2 specifies a "compatibility mode" in which the framework

            
            operates in an 'normal' screen size equivalent (320dp width) mode for the benefit

            
            of legacy applications not developed for old versions of Android that pre-date

            
            screen-size independence. Device implementations MUST include support for legacy

            
            application compatibility mode as implemented by the upstream Android open source

            
            code. That is, device implementations MUST NOT alter the triggers or thresholds at

            
            which compatibility mode is activated, and MUST NOT alter the behavior of the

            
            compatibility mode itself.</p>


            <a name="section-7.1.6"></a><h4>7.1.6. Screen Types</h4>

            
            <p>Device implementation screens are classified as one of two types:</p>

            
            <ul>

            
            <li>Fixed-pixel display implementations: the screen is a single panel that supports only a

            
            single pixel width and height. Typically the screen is physically integrated with

            
            the device. Examples include mobile phones, tablets, and so on.</li>

            
            <li>Variable-pixel display implementations: the device implementation either has no

            
            embedded screen and includes a video output port such as VGA, HDMI or a wireless port

            
            for display, or has an embedded screen that can change pixel dimensions. Examples

            
            include televisions, set-top boxes, and so on.</li>

            
            </ul>

            
            <p style="font-weight: bold;">Fixed-Pixel Device Implementations</p>

            
            <p>Fixed-pixel device implementations MAY use screens of any pixel dimensions, provided

            
            that they meet the requirements defined this Compatibility Definition.</p>

            
            <p>Fixed-pixel implementations MAY include a video output port for use with an

            
            external display. However, if that display is ever used for running apps, the

            
            device MUST meet the following requirements:</p>

            
            <ul>

            
            <li>The device MUST report the same screen configuration and display metrics, as detailed

            
            in Sections 7.1.1 and 7.1.2, as the fixed-pixel display.</li>

            
            <li>The device MUST report the same logical density as the fixed-pixel display.</li>

            
            <li>The device MUST report screen dimensions that are the same as, or very close to,

            
            the fixed-pixel display.</li>

            
            </ul>

            
            <p>For example, a tablet that is 7" diagonal size with a 1024x600 pixel resolution is

            
            considered a fixed-pixel large mdpi display implementation.  If it contains a video

            
            output port that displays at 720p or 1080p, the device implementation MUST scale the output so that

            
            applications are only executed in a large mdpi window, regardless of whether the fixed-pixel display

            
            or video output port is in use.</p>


            <p style="font-weight: bold;">Variable-Pixel Device Implementations</p>

            
            <p>Variable-pixel device implementations MUST support one or both of 1280x720,

            
            or 1920x1080 (that is, 720p or 1080p). Device implementations with

            
            variable-pixel displays MUST NOT support any other screen configuration or

            
            mode. Device implementations with variable-pixel screens MAY change screen

            
            configuration or mode at runtime or boot-time. For example, a user of a

            
            set-top box may replace a 720p display with a 1080p display, and the device

            
            implementation may adjust accordingly.</p>


            <p>Additionally, variable-pixel device implementations MUST report the following

            
            configuration buckets for these pixel dimensions:</p>

            
            <ul>

            
            <li>1280x720 (also known as 720p): 'large' screen size, 'tvdpi' (213 dpi)

            
            density</li>

            
            <li>1920x1080 (also known as 1080p): 'large' screen size, 'xhdpi' (320 dpi)

            
            density</li>

            
            </ul>

            
            <p>For clarity, device implementations with variable pixel dimensions are

            
            restricted to 720p or 1080p in Android 4.2, and MUST be configured to report

            
            screen size and density buckets as noted above.</p>


            <a name="section-7.1.7"></a><h4>7.1.7. Screen Technology</h4>

            
            <p>The Android platform includes APIs that allow applications to render rich

            
            graphics to the display. Devices MUST support all of these APIs as defined by

            
            the Android SDK unless specifically allowed in this document.  Specifically:</p>

            
            <ul>

            
            <li>Devices MUST support displays capable of rendering 16-bit color graphics and

            
            SHOULD support displays capable of 24-bit color graphics.</li>

            
            <li>Devices MUST support displays capable of rendering animations.</li>

            
            <li>The display technology used MUST have a pixel aspect ratio (PAR) between

            
                0.9 and 1.1. That is, the pixel aspect ratio MUST be near square (1.0) with

            
                a 10% tolerance.</li>

            
            </ul>

            
            <a name="section-7.1.8"></a><h4>7.1.8. External Displays</h4>

            
            <p>Android 4.2 includes support for secondary display to enable media sharing capabilities and

            
            developer APIs for accessing external displays. If a device supports an external display either via

            
            a wired, wireless or an embedded additional display connection then the device implementation MUST

            
            implement the display manager API as described in the Android SDK documentation [<a href="#resources75">Resources, 75</a>].

            
            Device implementations that support secure video output and are capable of supporting secure surfaces MUST declare support

            
            for <code>Display.SECURE_FLAG</code>. Specifically, device implementations that declare support for <code>Display.SECURE_FLAG</code>,

            
            MUST support <b>HDCP 2.x or higher</b> for Miracast wireless displays or <b>HDCP 1.2 or higher</b> for wired displays. The upstream

            
            Android open source implementation includes support for wireless (Miracast) and wired (HDMI) displays that satisfies this requirement.</p>


            <a name="section-7.2"></a><h3>7.2. Input Devices</h3>

            
            <a name="section-7.2.1"></a><h4>7.2.1. Keyboard</h4>

            
            <p>Device implementations:</p>

            
            <ul>

            
            <li>MUST include support for the Input Management Framework (which allows third

            
            party developers to create Input Management Engines - i.e. soft keyboard) as

            
            detailed at <a href="http://developer.android.com">http://developer.android.com</a>

            
            </li>

            
            <li>MUST provide at least one soft keyboard implementation (regardless of whether

            
            a hard keyboard is present)</li>

            
            <li>MAY include additional soft keyboard implementations</li>

            
            <li>MAY include a hardware keyboard</li>

            
            <li>MUST NOT include a hardware keyboard that does not match one of the

            
            formats specified in <code>android.content.res.Configuration.keyboard</code>

            
            [<a href="#resources40">Resources, 40</a>] (that is, QWERTY, or 12-key)</li>

            
            </ul>

            
            <a name="section-7.2.2"></a><h4>7.2.2. Non-touch Navigation</h4>

            
            <p>Device implementations:</p>

            
            <ul>

            
            <li>MAY omit a non-touch navigation option (that is, may omit a trackball, d-pad,

            
            or wheel)</li>

            
            <li>MUST report the correct value for

            
            <code>android.content.res.Configuration.navigation</code>

            
            [<a href="#resources40">Resources, 40</a>]</li>

            
            <li>MUST provide a reasonable alternative user interface mechanism for the

            
            selection and editing of text, compatible with Input Management Engines. The

            
            upstream Android open source implementation includes a selection mechanism suitable

            
            for use with devices that lack non-touch navigation inputs.</li>

            
            </ul>

            
            <a name="section-7.2.3"></a><h4>7.2.3. Navigation keys</h4>

            
            <p>The Home, Menu and Back functions are essential to the Android navigation

            
            paradigm. Device implementations MUST make these functions available to the

            
            user at all times when running applications. These functions MAY be implemented

            
            via dedicated physical buttons (such as mechanical or capacitive touch buttons),

            
            or MAY be implemented using dedicated software keys, gestures, touch panel, etc.

            
            Android 4.2 supports both implementations.</p>


            <p>Android 4.2 includes support for assist action [<a href="#resources63">Resources, 63</a>].

            
            Device implementations MUST make the assist action available to the user at all times when running applications.

            
            This function MAY be implemented via hardware or software keys.</p>


            <p>Device implementations MAY use a distinct portion of the screen to display

            
            the navigation keys, but if so, MUST meet these requirements:</p>


            <ul>

            
              <li>Device implementation navigation keys MUST use a distinct portion of the

            
                  screen, not available to applications, and MUST NOT obscure or otherwise

            
                  interfere with the portion of the screen available to applications.</li>

            
              <li>Device implementations MUST make available a portion of the display to

            
                  applications that meets the requirements defined in

            
                  <a href="section-7.1.1">Section 7.1.1</a>.</li>

            
              <li>Device implementations MUST display the navigation keys when applications

            
                  do not specify a system UI mode, or specify

            
                  <code>SYSTEM_UI_FLAG_VISIBLE</code>.</li>

            
              <li>Device implementations MUST present the navigation keys in an unobtrusive

            
                  "low profile" (eg. dimmed) mode when applications specify

            
                  <code>SYSTEM_UI_FLAG_LOW_PROFILE</code>.</li>

            
              <li>Device implementations MUST hide the navigation keys when applications

            
                  specify <code>SYSTEM_UI_FLAG_HIDE_NAVIGATION</code>.</li>

            
              <li>Device implementation MUST present a Menu key to applications when

            
                  targetSdkVersion &lt;= 10 and SHOULD NOT present a Menu key when the

            
                  targetSdkVersion &gt; 10.</li>

            
            </ul>


            <a name="section-7.2.4"></a><h4>7.2.4. Touchscreen input</h4>

            
            <p>Device implementations:</p>

            
            <ul>

            
            <li>MUST have a pointer input system of some kind (either mouse-like, or

            
            touch)</li>

            
            <li>MAY have a touchscreen of any modality (such as capacitive or resistive)</li>

            
            <li>SHOULD support fully independently tracked pointers, if a touchscreen

            
            supports multiple pointers</li>

            
            <li>MUST report the value of <code>android.content.res.Configuration</code>

            
            [<a href="#resources40">Resources, 39</a>]

            
            reflecting corresponding to the type of the specific touchscreen on the

            
            device</li>

            
            </ul>

            
            <p>Device implementations MUST report the correct feature corresponding to the

            
            type of input used. Note that Android 4.2 includes the feature

            
            <code>android.hardware.faketouch</code>, which corresponds to a high-fidelity

            
            non-touch (that is, pointer-based) input device such as a mouse or trackpad that

            
            can adequately emulate touch-based input (including basic gesture support),

            
            and indicates that the device supports an emulated subset of touchscreen

            
            functionality.

            
            Device implementations that include a touchscreen (single-touch or better)

            
            MUST also report android.hardware.faketouch. Device implementations that do

            
            not include a touchscreen (and rely on a pointer device only) MUST NOT report

            
            any touchscreen feature, and MUST report only

            
            <code>android.hardware.faketouch</code>.</p>

            
            <a name="section-7.2.5"></a><h4>7.2.5. Microphone</h4>

            
            <p>Device implementations MAY omit a microphone. However, if a device

            
            implementation omits a microphone, it MUST NOT report the

            
            <code>android.hardware.microphone</code> feature constant, and must implement

            
            the audio recording API as no-ops, per <a href="section-7">Section 7</a>.

            
            Conversely, device implementations that do possess a microphone:</p>

            
            <ul>

            
            <li>MUST report the <code>android.hardware.microphone</code> feature constant</li>

            
            <li>SHOULD meet the audio quality requirements in <a href="section-5.4">Section 5.4</a></li>

            
            <li>SHOULD meet the audio latency requirements in <a href="section-5.5">Section 5.5</a></li>

            
            </ul>


            <a name="section-7.3"></a><h3>7.3. Sensors</h3>

            
            <p>Android 4.2 includes APIs for accessing a variety of sensor types. Devices

            
            implementations generally MAY omit these sensors, as provided for in the

            
            following subsections. If a device includes a particular sensor type that has a

            
            corresponding API for third-party developers, the device implementation MUST

            
            implement that API as described in the Android SDK documentation. For example,

            
            device implementations:</p>

            
            <ul>

            
            <li>MUST accurately report the presence or absence of sensors per the

            
            <code>android.content.pm.PackageManager</code> class. [<a

            
            href="#resources37">Resources, 37</a>]</li>

            
            <li>MUST return an accurate list of supported sensors via the

            
            <code>SensorManager.getSensorList()</code> and similar methods</li>

            
            <li>MUST behave reasonably for all other sensor APIs (for example, by

            
            returning true or false as appropriate when applications attempt to register

            
            listeners, not calling sensor listeners when the corresponding sensors are not

            
            present; etc.)</li>

            
            <li>MUST report all sensor measurements using the relevant International System

            
            of Units (i.e. metric) values for each sensor type as defined in the Android SDK

            
            documentation [<a href="#resources41">Resources, 41</a>]</li>

            
            </ul>

            
            <p>The list above is not comprehensive; the documented behavior of the Android

            
            SDK is to be considered authoritative.</p>

            
            <p>Some sensor types are synthetic, meaning they can be derived from data

            
            provided by one or more other sensors. (Examples include the orientation

            
            sensor, and the linear acceleration sensor.) Device implementations SHOULD

            
            implement these sensor types, when they include the prerequisite physical

            
            sensors.</p>

            
            <p>The Android 4.2 includes a notion of a "streaming" sensor, which is

            
            one that returns data continuously, rather than only when the data changes.

            
            Device implementations MUST continuously provide periodic data samples for any

            
            API indicated by the Android 4.2 SDK documentation to be a streaming

            
            sensor. Note that the device implementations MUST ensure that the sensor stream must not

            
            prevent the device CPU from entering a suspend state or waking up from a suspend state.</p>


            <a name="section-7.3.1"></a><h4>7.3.1. Accelerometer</h4>

            
            <p>Device implementations SHOULD include a 3-axis accelerometer. If a device

            
            implementation does include a 3-axis accelerometer, it:</p>

            
            <ul>

            
            <li>SHOULD be able to deliver events at 120 Hz or greater. Note that while the

            
            accelerometer frequency above is stated as "SHOULD" for Android 4.2, the Compatibility Definition

            
            for a future version is planned to change these to "MUST". That is, these standards are

            
            optional in Android 4.2 but <b>will be required</b> in future versions. Existing and

            
            new devices that run Android 4.2 are <b>very strongly encouraged to meet these requirements

            
            in Android 4.2</b> so they will be able to upgrade to the future platform releases

            
            </li>

            
            <li>MUST comply with the Android sensor coordinate system as detailed

            
            in the Android APIs (see [<a href="#resources41">Resources, 41</a>])</li>

            
            <li>MUST be capable of measuring from freefall up to twice gravity (2g) or

            
            more on any three-dimensional vector</li>

            
            <li>MUST have 8-bits of accuracy or more</li>

            
            <li>MUST have a standard deviation no greater than 0.05 m/s^2</li>

            
            </ul>

            
            <a name="section-7.3.2"></a><h4>7.3.2. Magnetometer</h4>

            
            <p>Device implementations SHOULD include a 3-axis magnetometer (i.e. compass.)

            
            If a device does include a 3-axis magnetometer, it:</p>

            
            <ul>

            
            <li>MUST be able to deliver events at 10 Hz or greater</li>

            
            <li>MUST comply with the Android sensor coordinate system as detailed

            
            in the Android APIs (see [<a href="#resources41">Resources, 41</a>]).</li>

            
            <li>MUST be capable of sampling a range of field strengths adequate to cover the

            
            geomagnetic field</li>

            
            <li>MUST have 8-bits of accuracy or more</li>

            
            <li>MUST have a standard deviation no greater than 0.5 &micro;T</li>

            
            </ul>

            
            <a name="section-7.3.3"></a><h4>7.3.3. GPS</h4>

            
            <p>Device implementations SHOULD include a GPS receiver. If a device

            
            implementation does include a GPS receiver, it SHOULD include

            
            some form of "assisted GPS" technique to minimize GPS lock-on time.</p>

            
            <a name="section-7.3.4"></a><h4>7.3.4. Gyroscope</h4>

            
            <p>Device implementations SHOULD include a gyroscope (i.e. angular change

            
            sensor.) Devices SHOULD NOT include a gyroscope sensor unless a 3-axis

            
            accelerometer is also included. If a device implementation includes a

            
            gyroscope, it:</p>

            
            <ul>

            
            <li>MUST be temperature compensated</li>

            
            <li>MUST be capable of measuring orientation changes up to 5.5*Pi

            
            radians/second (that is, approximately 1,000 degrees per second)</li>

            
            <li>SHOULD be able to deliver events at 200 Hz or greater. Note that while the

            
            gyroscope frequency above is stated as "SHOULD" for Android 4.2, the Compatibility Definition

            
            for a future version is planned to change these to "MUST". That is, these standards are

            
            optional in Android 4.2 but <b>will be required</b> in future versions. Existing and

            
            new devices that run Android 4.2 are <b>very strongly encouraged to meet these requirements

            
            in Android 4.2</b> so they will be able to upgrade to the future platform releases

            
            </li>

            
            <li>MUST have 12-bits of accuracy or more</li>

            
            <li>MUST have a variance no greater than 1e-7 rad^2 / s^2 per Hz (variance per Hz, or rad^2 / s).

            
            The variance is allowed to vary with the sampling rate, but must be constrained by this value.

            
            In other words, if you measure the variance of the gyro at 1 Hz sampling rate it should be no

            
            greater than 1e-7 rad^2/s^2. </li>

            
            <li>MUST have timestamps as close to when the hardware event happened as possible. The constant latency must be removed.</li>

            
            </ul>

            
            <a name="section-7.3.5"></a><h4>7.3.5. Barometer</h4>

            
            <p>Device implementations MAY include a barometer (i.e. ambient air pressure

            
            sensor.) If a device implementation includes a barometer, it:</p>

            
            <ul>

            
            <li>MUST be able to deliver events at 5 Hz or greater</li>

            
            <li>MUST have adequate precision to enable estimating altitude</li>

            
            <li>MUST be temperature compensated</li>

            
            </ul>

            
            <a name="section-7.3.6"></a><h4>7.3.7. Thermometer</h4>

            
            <p>Device implementations MAY but SHOULD NOT include a thermometer (i.e.

            
            temperature sensor.) If a device implementation does include a thermometer, it

            
            MUST measure the temperature of the device CPU. It MUST NOT measure any other

            
            temperature. (Note that this sensor type is deprecated in the Android 4.2

            
            APIs.)</p>

            
            <a name="section-7.3.7"></a><h4>7.3.7. Photometer</h4>

            
            <p>Device implementations MAY include a photometer (i.e. ambient light

            
            sensor.)</p>

            
            <a name="section-7.3.8"></a><h4>7.3.8. Proximity Sensor</h4>

            
            <p>Device implementations MAY include a proximity sensor.  If a device

            
            implementation does include a proximity sensor, it MUST measure the proximity

            
            of an object in the same direction as the screen. That is, the proximity

            
            sensor MUST be oriented to detect objects close to the screen, as the

            
            primary intent of this sensor type is to detect a phone in use by the

            
            user. If a device implementation includes a proximity sensor with any other

            
            orientation, it MUST NOT be accessible through this API. If a device

            
            implementation has a proximity sensor, it MUST be have 1-bit of accuracy or

            
            more.</p>


            <a name="section-7.4"></a><h3>7.4. Data Connectivity</h3>

            
            <a name="section-7.4.1"></a><h4>7.4.1. Telephony</h4>

            
            <p>"Telephony" as used by the Android 4.2 APIs and this document refers

            
            specifically to hardware related to placing voice calls and sending SMS

            
            messages via a GSM or CDMA network. While these voice calls may or may not be

            
            packet-switched, they are for the purposes of Android 4.2 considered

            
            independent of any data connectivity that may be implemented using the same

            
            network. In other words, the Android "telephony" functionality and APIs refer

            
            specifically to voice calls and SMS; for instance, device implementations that

            
            cannot place calls or send/receive SMS messages MUST NOT report the

            
            "android.hardware.telephony" feature or any sub-features, regardless of

            
            whether they use a cellular network for data connectivity.</p>

            
            <p>Android 4.2 MAY be used on devices that do not include telephony hardware.

            
            That is, Android 4.2 is compatible with devices that are not phones.

            
            However, if a device implementation does include GSM or CDMA telephony, it

            
            MUST implement full support for the API for that technology. Device

            
            implementations that do not include telephony hardware MUST implement the full

            
            APIs as no-ops.</p>

            
            <a name="section-7.4.2"></a><h4>7.4.2. IEEE 802.11 (WiFi)</h4>

            
            <p>Android 4.2 device implementations SHOULD include support for one or more

            
            forms of 802.11 (b/g/a/n, etc.) If a device implementation does include

            
            support for 802.11, it MUST implement the corresponding Android API.</p>

            
            <p>Device implementations MUST implement the multicast API as described in

            
            the SDK documentation [<a href="#resources62">Resources, 62</a>]. Device

            
            implementations that do include Wifi support MUST support multicast DNS (mDNS).

            
            Device implementations MUST not filter mDNS packets (224.0.0.251) at any time

            
            of operation including when the screen is not in an active state.</p>


            <a name="section-7.4.2.1"></a><h4>7.4.2.1. WiFi Direct</h4>

            
            <p>Device implementations SHOULD include support for Wifi direct (Wifi peer-to-peer).

            
            If a device implementation does include support for Wifi direct, it MUST implement the corresponding

            
            Android API as described in the SDK documentation [<a href="#resources68">Resources, 68</a>].

            
            If a device implementation includes support for Wifi direct, then it:</p>

            
            <ul>

            
              <li>MUST support regular Wifi operation</li>

            
              <li>SHOULD support concurrent wifi and wifi Direct operation</li>

            
            </ul>


            <a name="section-7.4.3"></a><h4>7.4.3. Bluetooth</h4>

            
            <p>Device implementations SHOULD include a Bluetooth transceiver. Device

            
            implementations that do include a Bluetooth transceiver MUST enable the

            
            RFCOMM-based Bluetooth API as described in the SDK documentation [<a

            
            href="#resources42">Resources, 42</a>]. Device implementations SHOULD

            
            implement relevant Bluetooth profiles, such as A2DP, AVRCP, OBEX, etc. as

            
            appropriate for the device.</p>

            
            <p>The Compatibility Test Suite includes cases that cover basic operation of

            
            the Android RFCOMM Bluetooth API. However, since Bluetooth is a communications

            
            protocol between devices, it cannot be fully tested by unit tests running on a

            
            single device. Consequently, device implementations MUST also pass the

            
            human-driven Bluetooth test procedure described in Appendix A.</p>


            <a name="section-7.4.4"></a><h4>7.4.4. Near-Field Communications</h4>

            
            <p>Device implementations SHOULD include a transceiver and related hardware

            
            for Near-Field Communications (NFC). If a device implementation does include

            
            NFC hardware, then it:</p>

            
            <ul>

            
              <li>MUST report the android.hardware.nfc feature from the

            
                  <code>android.content.pm.PackageManager.hasSystemFeature()</code> method.

            
                  [<a href="#resources37">Resources, 37</a>]</li>

            
              <li>MUST be capable of reading and writing NDEF messages via the following NFC

            
                  standards:

            
               <ul>

            
                <li>MUST be capable of acting as an NFC Forum reader/writer

            
                    (as defined by the NFC Forum technical specification

            
                    NFCForum-TS-DigitalProtocol-1.0) via the following NFC standards:

            
                 <ul>

            
                  <li>NfcA (ISO14443-3A)</li>

            
                  <li>NfcB (ISO14443-3B) </li>

            
                  <li>NfcF (JIS 6319-4)</li>

            
                  <li>IsoDep (ISO 14443-4)</li>

            
                  <li>NFC Forum Tag Types 1, 2, 3, 4 (defined by the NFC Forum)</li>

            
                 </ul>

            
                </li>

            
               </ul>

            
              </li>

            
              <li>SHOULD be capable of reading and writing NDEF messages via the following

            
                  NFC standards. Note that while the NFC standards below are stated as

            
                  "SHOULD" for Android 4.2, the Compatibility Definition for a future

            
                  version is planned to change these to "MUST". That is, these standards are

            
                  optional in Android 4.2 but <b>will be required</b> in future versions.

            
                  Existing and new devices that run Android 4.2 are <b>very strongly

            
                  encouraged to meet these requirements in Android 4.2</b> so they will be

            
                  able to upgrade to the future platform releases.

            
                <ul>

            
                  <li>NfcV (ISO 15693)</li>

            
                </ul>

            
              </li>

            
              <li>MUST be capable of transmitting and receiving data via the following

            
                  peer-to-peer standards and protocols:

            
                <ul>

            
                  <li>ISO 18092</li>

            
                  <li>LLCP 1.0 (defined by the NFC Forum)</li>

            
                  <li>SDP 1.0 (defined by the NFC Forum)</li>

            
                  <li>NDEF Push Protocol [<a href="#resources43">Resources, 43</a>]</li>

            
                  <li>SNEP 1.0 (defined by the NFC Forum)</li>

            
                </ul>

            
              </li>

            
              <li>MUST include support for Android Beam [<a href="#resources65">Resources, 65</a>]:

            
               <ul>

            
                <li>MUST implement the SNEP default server. Valid NDEF messages received

            
                    by the default SNEP server MUST be dispatched to applications using

            
                    the android.nfc.ACTION_NDEF_DISCOVERED intent. Disabling Android Beam

            
                    in settings MUST NOT disable dispatch of incoming NDEF message.</li>

            
                <li>Device implementations MUST honor the android.settings.NFCSHARING_SETTINGS intent

            
                    to show NFC sharing settings [<a href="#resources67">Resources, 67</a>].</li>

            
                <li>MUST implement the NPP server. Messages received by the NPP server MUST

            
                    be processed the same way as the SNEP default server.</li>

            
                <li>MUST implement a SNEP client and attempt to send outbound P2P NDEF to

            
                    the default SNEP server when Android Beam is enabled. If no default

            
                    SNEP server is found then the client MUST attempt to send to an NPP

            
                    server.</li>

            
                <li>MUST allow foreground activities to set the outbound P2P NDEF message

            
                    using android.nfc.NfcAdapter.setNdefPushMessage, and

            
                    android.nfc.NfcAdapter.setNdefPushMessageCallback, and

            
                    android.nfc.NfcAdapter.enableForegroundNdefPush.</li>

            
                <li>SHOULD use a gesture or on-screen confirmation, such as 'Touch to Beam',

            
                    before sending outbound P2P NDEF messages.</li>

            
                <li>SHOULD enable Android Beam by default</li>

            
                <li>MUST support NFC Connection handover to Bluetooth when the device supports Bluetooth Object Push Profile.

            
                    Device implementations must support connection handover to Bluetooth when using android.nfc.NfcAdapter.setBeamPushUris,

            
                    by implementing the "Connection Handover version 1.2" [<a href="#resources60">Resources, 60</a>]

            
                    and "Bluetooth Secure Simple Pairing Using NFC version 1.0" [<a href="#resources61">Resources, 61</a>]

            
                    specs from the NFC Forum. Such an implementation SHOULD use SNEP GET

            
                    requests for exchanging the handover request / select records over NFC, and it MUST

            
                    use the Bluetooth Object Push Profile for the actual Bluetooth data transfer.</li>

            
               </ul>

            
              </li>

            
              <li>MUST poll for all supported technologies while in NFC discovery mode.</li>

            
              <li>SHOULD be in NFC discovery mode while the device is awake with the screen active

            
                  and the lock-screen unlocked.</li>

            
            </ul>


            <p>(Note that publicly available links are not available for the JIS, ISO, and

            
            NFC Forum specifications cited above.)</p>

            
            <p>Additionally, device implementations MAY include reader/writer support for

            
            the following MIFARE technologies.</p>

            
            <ul>

            
              <li>MIFARE Classic (NXP MF1S503x [<a href="#resources44">Resources, 44</a>],

            
                  MF1S703x [<a href="#resources44">Resources, 44</a>])</li>

            
              <li>MIFARE Ultralight (NXP MF0ICU1 [<a href="#resources46">Resources, 46</a>],

            
                  MF0ICU2 [<a href="#resources46">Resources, 46</a>])</li>

            
              <li>NDEF on MIFARE Classic (NXP AN130511 [<a href="#resources48">Resources, 48</a>],

            
                  AN130411 [<a href="#resources49">Resources, 49</a>])</li>

            
            </ul>

            
            <p>Note that Android 4.2 includes APIs for these MIFARE types. If a

            
            device implementation supports MIFARE in the reader/writer role, it:</p>

            
            <ul>

            
              <li>MUST implement the corresponding Android APIs as documented by the

            
              Android SDK</li>

            
              <li>MUST report the feature com.nxp.mifare from the

            
              <code>android.content.pm.PackageManager.hasSystemFeature()</code> method.

            
              [<a href="#resources37">Resources, 37</a>] Note that this is not a standard

            
              Android feature, and as such does not appear as a constant on the

            
              <code>PackageManager</code> class.</li>

            
              <li>MUST NOT implement the corresponding Android APIs nor report the

            
              com.nxp.mifare feature unless it also implements general NFC support as

            
              described in this section</li>

            
            </ul>

            
            <p>If a device implementation does not include NFC hardware, it MUST NOT

            
            declare the android.hardware.nfc feature from the

            
            <code>android.content.pm.PackageManager.hasSystemFeature()</code> method [<a

            
            href="#resources37">Resources, 37</a>], and MUST implement the Android 4.2 NFC

            
            API as a no-op.</p>

            
            <p>As the classes <code>android.nfc.NdefMessage</code> and

            
            <code>android.nfc.NdefRecord</code> represent a protocol-independent data

            
            representation format, device implementations MUST implement these APIs even

            
            if they do not include support for NFC or declare the android.hardware.nfc

            
            feature.</p>

            
            <a name="section-7.4.5"></a><h4>7.4.5. Minimum Network Capability</h4>

            
            <p>Device implementations MUST include support for one or more forms of data

            
            networking. Specifically, device implementations MUST include support for at

            
            least one data standard capable of 200Kbit/sec or greater. Examples of

            
            technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g,

            
            Ethernet, etc.</p>

            
            <p>Device implementations where a physical networking standard (such as

            
            Ethernet) is the primary data connection SHOULD also include support for at

            
            least one common wireless data standard, such as 802.11 (WiFi).</p>

            
            <p>Devices MAY implement more than one form of data connectivity.</p>


            <a name="section-7.5"></a><h3>7.5. Cameras</h3>

            
            <p>Device implementations SHOULD include a rear-facing camera, and MAY include

            
            a front-facing camera. A rear-facing camera is a camera located on the side of

            
            the device opposite the display; that is, it images scenes on the far side of

            
            the device, like a traditional camera. A front-facing camera is a camera

            
            located on the same side of the device as the display; that is, a camera

            
            typically used to image the user, such as for video conferencing and similar

            
            applications.</p>

            
            <a name="section-7.5.1"></a><h4>7.5.1. Rear-Facing Camera</h4>

            
            <p>Device implementations SHOULD include a rear-facing camera. If a device

            
            implementation includes a rear-facing camera, it:</p>

            
            <ul>

            
            <li>MUST have a resolution of at least 2 megapixels</li>

            
            <li>SHOULD have either hardware auto-focus, or software auto-focus implemented

            
            in the camera driver (transparent to application software)</li>

            
            <li>MAY have fixed-focus or EDOF (extended depth of field) hardware</li>

            
            <li>MAY include a flash. If the Camera includes a flash, the flash lamp MUST

            
            NOT be lit while an android.hardware.Camera.PreviewCallback instance has been

            
            registered on a Camera preview surface, unless the application has explicitly

            
            enabled the flash by enabling the <code>FLASH_MODE_AUTO</code> or

            
            <code>FLASH_MODE_ON</code> attributes of a <code>Camera.Parameters</code>

            
            object. Note that this constraint does not apply to the device's built-in

            
            system camera application, but only to third-party applications using

            
            <code>Camera.PreviewCallback</code>.</li>

            
            </ul>

            
            <a name="section-7.5.2"></a><h4>7.5.2. Front-Facing Camera</h4>

            
            <p>Device implementations MAY include a front-facing camera. If a device

            
            implementation includes a front-facing camera, it:</p>

            
            <ul>

            
            <li>MUST have a resolution of at least VGA (that is, 640x480 pixels)</li>

            
            <li>MUST NOT use a front-facing camera as the default for the Camera API.

            
            That is, the camera API in Android 4.2 has specific support for front-facing

            
            cameras, and device implementations MUST NOT configure the API to to treat a

            
            front-facing camera as the default rear-facing camera, even if it is the only

            
            camera on the device.</li>

            
            <li>MAY include features (such as auto-focus, flash, etc.)

            
            available to rear-facing cameras as described in Section 7.5.1.</li>

            
            <li>MUST horizontally reflect (i.e. mirror) the stream displayed by an app in a

            
            CameraPreview, as follows:</li>

            
            <ul>

            
            <li>If the device implementation is capable of being rotated by user (such as

            
            automatically via an accelerometer or manually via user input), the camera

            
            preview MUST be mirrored horizontally relative to the device's current

            
            orientation.</li>

            
            <li>If the current application has explicitly requested that the Camera

            
            display be rotated via a call to the

            
            <code>android.hardware.Camera.setDisplayOrientation()</code> [<a

            
            href="#resources50">Resources, 50</a>] method, the camera preview MUST be

            
            mirrored horizontally relative to the orientation specified by the

            
            application.</li>

            
            <li>Otherwise, the preview MUST be mirrored along the device's default horizontal axis.</li>

            
            </ul>

            
            <li>MUST mirror the image displayed by the postview in the same manner as

            
            the camera preview image stream. (If the device implementation does not

            
            support postview, this requirement obviously does not apply.)</li>

            
            <li>MUST NOT mirror the final captured still image or video streams returned

            
            to application callbacks or committed to media storage</li>

            
            </ul>

            
            <a name="section-7.5.3"></a><h4>7.5.3. Camera API Behavior</h4>

            
            <p>Device implementations MUST implement the following behaviors for the

            
            camera-related APIs, for both front- and rear-facing cameras:</p>

            
            <ol>

            
            <li>If an application has never called

            
            <code>android.hardware.Camera.Parameters.setPreviewFormat(int)</code>, then the

            
            device MUST use <code>android.hardware.PixelFormat.YCbCr_420_SP</code> for

            
            preview data provided to application callbacks.</li>

            
            <li>If an application registers an <code>android.hardware.Camera.PreviewCallback

            
            </code> instance and the system calls the <code>onPreviewFrame()</code> method

            
            when the preview format is YCbCr_420_SP, the data in the <code>byte[]</code>

            
            passed into <code>onPreviewFrame()</code> must further be in the NV21 encoding

            
            format. That is, NV21 MUST be the default.</li>

            
            <li>Device implementations MUST support the YV12 format (as denoted by the

            
            <code>android.graphics.ImageFormat.YV12</code> constant) for camera previews

            
            for both front- and rear-facing cameras.  (The hardware video encoder and camera

            
            may use any native pixel format, but the device implementation MUST support conversion

            
            to YV12.)</li>

            
            </ol>

            
            <p>Device implementations MUST implement the full Camera API included in the

            
            Android 4.2 SDK documentation [<a href="#resources51">Resources, 51</a>]),

            
            regardless of whether the device includes hardware autofocus or other

            
            capabilities. For instance, cameras that lack autofocus MUST still call any

            
            registered <code>android.hardware.Camera.AutoFocusCallback</code> instances (even though

            
            this has no relevance to a non-autofocus camera.) Note that this does apply

            
            to front-facing cameras; for instance, even though most front-facing cameras

            
            do not support autofocus, the API callbacks must still be "faked" as

            
            described.</p>

            
            <p>Device implementations MUST recognize and honor each parameter name defined

            
            as a constant on the <code>android.hardware.Camera.Parameters</code> class, if the

            
            underlying hardware supports the feature. If the device hardware does not

            
            support a feature, the API must behave as documented. Conversely, Device

            
            implementations MUST NOT honor or recognize string constants passed

            
            to the <code>android.hardware.Camera.setParameters()</code> method other than

            
            those documented as constants on the

            
            <code>android.hardware.Camera.Parameters</code>.  That is,

            
            device implementations MUST support all standard Camera parameters if the

            
            hardware allows, and MUST NOT support custom Camera parameter types.

            
            For instance, device implementations that support image capture using high dynamic range (HDR)

            
            imaging techniques MUST support camera parameter <code>Camera.SCENE_MODE_HDR</code>

            
            [<a href="#resources78">Resources, 78</a>]).</p>

            
            <p>Device implementations MUST broadcast the <code>Camera.ACTION_NEW_PICTURE</code>

            
            intent whenever a new picture is taken by the camera and the entry of the picture

            
            has been added to the media store.</p>

            
            <p>Device implementations MUST broadcast the <code>Camera.ACTION_NEW_VIDEO</code>

            
            intent whenever a new video is recorded by the camera and the entry of the picture

            
            has been added to the media store.</p>

            
            <a name="section-7.5.4"></a><h4>7.5.4. Camera Orientation</h4>

            
            <p>Both front- and rear-facing cameras, if present, MUST be oriented so that

            
            the long dimension of the camera aligns with the screen's long dimention. That

            
            is, when the device is held in the landscape orientation, cameras MUST

            
            capture images in the landscape orientation. This applies regardless of the

            
            device's natural orientation; that is, it applies to landscape-primary devices

            
            as well as portrait-primary devices.</p>


            <a name="section-7.6"></a><h3>7.6. Memory and Storage</h3>

            
            <a name="section-7.6.1"></a><h4>7.6.1. Minimum Memory and Storage</h4>

            
            <p>Device implementations MUST have at least 340MB of memory available to the

            
            kernel and userspace. The 340MB MUST be in addition to any memory dedicated to

            
            hardware components such as radio, video, and so on that is not under the

            
            kernel's control.</p>

            
            <p>Device implementations MUST have at least 350MB of non-volatile storage

            
            available for application private data. That is, the <code>/data</code> partition MUST be at

            
            least 350MB.</p>

            
            <p>The Android APIs include a Download Manager that applications may use to

            
            download data files [<a href="#resources56">Resources, 56</a>]. The device

            
            implementation of the Download Manager MUST be capable of downloading individual

            
            files of at least 100MB in size to the default "cache" location.</p>

            
            <a name="section-7.6.2"></a><h4>7.6.2. Application Shared Storage</h4>

            
            <p>Device implementations MUST offer shared storage for applications. The

            
            shared storage provided MUST be at least 1GB in size.</p>

            
            <p>Device implementations MUST be configured with shared storage mounted by

            
            default, "out of the box". If the shared storage is not mounted on the Linux

            
            path <code>/sdcard</code>, then the device MUST include a Linux symbolic link

            
            from <code>/sdcard</code> to the actual mount point.</p>

            
            <p>Device implementations MUST enforce as documented the

            
            <code>android.permission.WRITE_EXTERNAL_STORAGE</code> permission on this

            
            shared storage. Shared storage MUST otherwise be writable by any application

            
            that obtains that permission.</p>

            
            <p>Device implementations MAY have hardware for user-accessible removable

            
            storage, such as a Secure Digital card. Alternatively, device implementations

            
            MAY allocate internal (non-removable) storage as shared storage for apps.</p>

            
            <p>Regardless of the form of shared storage used, device implementations MUST

            
            provide some mechanism to access the contents of shared storage from a host

            
            computer, such as USB mass storage (UMS) or Media Transfer Protocol (MTP). Device

            
            implementations MAY use USB mass storage, but SHOULD use Media Transfer

            
            Protocol. If the device implementation supports Media Transfer Protocol:</p>

            
            <ul>

            
            <li>The device implementation SHOULD be compatible with the reference Android

            
            MTP host, Android File Transfer [<a href="#resources57">Resources, 57</a>].</li>

            
            <li>The device implementation SHOULD report a USB device class of <code>0x00</code>.</li>

            
            <li>The device implementation SHOULD report a USB interface name of 'MTP'.</li>

            
            </ul>

            
            <p>If the device implementation lacks USB ports, it MUST provide a host

            
            computer with access to the contents of shared storage by some other means,

            
            such as a network file system.</p>

            
            <p>It is illustrative to consider two common examples. If a device

            
            implementation includes an SD card slot to satisfy the shared storage

            
            requirement, a FAT-formatted SD card 1GB in size or larger MUST be included

            
            with the device as sold to users, and MUST be mounted by default.

            
            Alternatively, if a device implementation uses internal fixed storage to

            
            satisfy this requirement, that storage MUST be 1GB in size or larger

            
            and mounted on <code>/sdcard</code> (or <code>/sdcard</code>

            
            MUST be a symbolic link to the physical location if it is mounted elsewhere.)</p>

            
            <p>Device implementations that include multiple shared storage paths (such as

            
            both an SD card slot and shared internal storage) SHOULD modify the core

            
            applications such as the media scanner and ContentProvider to transparently

            
            support files placed in both locations.</p>


            <a name="section-7.7"></a><h3>7.7. USB</h3>

            
            <p>Device implementations SHOULD include a USB client port, and SHOULD include

            
            a USB host port.</p>

            
            <p>If a device implementation includes a USB client port:</p>

            
            <ul>

            
            <li>the port MUST be connectable to a USB host with a standard USB-A port</li>

            
            <li>the port SHOULD use the micro USB form factor on the device side. Existing and

            
            new devices that run Android 4.2 are <b>very strongly encouraged to meet these requirements

            
            in Android 4.2</b> so they will be able to upgrade to the future platform releases</li>

            
            <li>the port SHOULD be centered in the middle of an edge. Device implementations SHOULD either

            
            locate the port on the bottom of the device (according to natural orientation) or enable software

            
            screen rotation for all apps (including home screen), so that the display draws correctly when the device

            
            is oriented with the port at bottom. Existing and new devices that run Android 4.2 are <b>very strongly

            
            encouraged to meet these requirements in Android 4.2</b> so they will be able to upgrade to future platform releases.</li>

            
            <li>if the device has other ports (such as a non-USB charging port) it SHOULD be on the same edge as the

            
            micro-USB port</li>

            
            <li>it MUST allow a host connected to the device to access the contents of the

            
            shared storage volume using either USB mass storage or Media Transfer

            
            Protocol</li>

            
            <li>it MUST implement the Android Open Accessory API and specification as documented

            
            in the Android SDK documentation, and MUST declare support for the hardware

            
            feature <code>android.hardware.usb.accessory</code> [<a href="#resources52">Resources,

            
            52</a>]</li>

            
            <li>it MUST implement the USB audio class as documented in the Android SDK documentation [<a href="#resources66">Resources, 66</a>]</li>

            
            <li>it SHOULD implement support for USB battery charging specification [<a href="#resources64">Resources, 64</a>]

            
            Existing and new devices that run Android 4.2 are <b>very strongly encouraged to meet these requirements in Android 4.2</b>

            
            so they will be able to upgrade to the future platform releases</li>


            </ul>

            
            <p>If a device implementation includes a USB host port:</p>

            
            <ul>

            
            <li>it MAY use a non-standard port form factor, but if so MUST ship with a

            
            cable or cables adapting the port to standard USB-A</li>

            
            <li>it MUST implement the Android USB host API as documented in the Android

            
            SDK, and MUST declare support for the hardware feature

            
            <code>android.hardware.usb.host</code> [<a href="#resources53">Resources, 53</a>]</li>

            
            </ul>

            
            <p>Device implementations MUST implement the Android Debug Bridge. If a device

            
            implementation omits a USB client port, it MUST implement the Android Debug

            
            Bridge via local-area network (such as Ethernet or 802.11)</p>


            <a name="section-8"></a><h2>8. Performance Compatibility</h2>

            
            <p>Device implementations MUST meet the key performance metrics of an Android

            
            4.2 compatible device defined in the table below:</p>

            
            <table><tbody><tr>

            
            <td><b>Metric</b></td>

            
            <td><b>Performance Threshold</b></td>

            
            <td><b>Comments</b></td>

            
            </tr>

            
            <tr>

            
            <td>Application Launch Time</td>

            
            <td>The following applications should launch within the specified time.<ul>

            
            <li>Browser: less than 1300ms</li>

            
            <li>Contacts: less than 700ms</li>

            
            <li>Settings: less than 700ms</li>

            
            </ul></td>

            
            <td>The launch time is measured as the total time to

            
            complete loading the default activity for the application, including the time

            
            it takes to start the Linux process, load the Android package into the Dalvik

            
            VM, and call onCreate.</td>

            
            </tr>

            
            <tr>

            
            <td>Simultaneous Applications</td>

            
            <td>When multiple applications have been launched, re-launching an

            
            already-running application after it has been launched must take less than the

            
            original launch time.</td>

            
            <td>&nbsp;</td>

            
            </tr>

            
            </tbody>

            
            </table>


            <a name="section-9"></a><h2>9. Security Model Compatibility</h2>

            
            <p>Device implementations MUST implement a security model consistent with the

            
            Android platform security model as defined in Security and Permissions

            
            reference document in the APIs [<a href="#resources54">Resources, 54</a>] in the

            
            Android developer documentation. Device implementations MUST support

            
            installation of self-signed applications without requiring any additional

            
            permissions/certificates from any third parties/authorities.  Specifically,

            
            compatible devices MUST support the security mechanisms described in the

            
            follow sub-sections.</p>

            
            <a name="section-9.1"></a><h3>9.1. Permissions</h3>

            
            <p>Device implementations MUST support the Android permissions model as

            
            defined in the Android developer documentation [<a

            
            href="#resources54">Resources, 54</a>]. Specifically,

            
            implementations MUST enforce each permission defined as described in the SDK

            
            documentation; no permissions may be omitted, altered, or ignored.

            
            Implementations MAY add additional permissions, provided the new permission ID

            
            strings are not in the android.* namespace.</p>

            
            <a name="section-9.2"></a><h3>9.2. UID and Process Isolation</h3>

            
            <p>Device implementations MUST support the Android application sandbox model,

            
            in which each application runs as a unique Unix-style UID and in a separate

            
            process.  Device implementations MUST support running multiple applications as

            
            the same Linux user ID, provided that the applications are properly signed and

            
            constructed, as defined in the Security and Permissions reference [<a

            
            href="#resources54">Resources, 54</a>].</p>

            
            <a name="section-9.3"></a><h3>9.3. Filesystem Permissions</h3>

            
            <p>Device implementations MUST support the Android file access permissions

            
            model as defined in as defined in the Security and Permissions reference [<a

            
            href="#resources54">Resources, 54</a>].</p>

            
            <a name="section-9.4"></a><h3>9.4. Alternate Execution Environments</h3>

            
            <p>Device implementations MAY include runtime environments that execute

            
            applications using some other software or technology than the Dalvik virtual

            
            machine or native code. However, such alternate execution environments MUST

            
            NOT compromise the Android security model or the security of installed Android

            
            applications, as described in this section.</p>

            
            <p>Alternate runtimes MUST themselves be Android applications, and abide by

            
               the standard Android security model, as described elsewhere in Section 9.</p>

            
            <p>Alternate runtimes MUST NOT be granted access to resources protected by

            
               permissions not requested in the runtime's AndroidManifest.xml file via the

            
               <code>&lt;uses-permission&gt;</code> mechanism.</p>

            
            <p>Alternate runtimes MUST NOT permit applications to make use of features

            
               protected by Android permissions restricted to system applications.</p>

            
            <p>Alternate runtimes MUST abide by the Android sandbox model.  Specifically:</p>

            
            <ul>

            
            <li>Alternate runtimes SHOULD install apps via the PackageManager into

            
                separate Android sandboxes (that is, Linux user IDs, etc.)</li>

            
            <li>Alternate runtimes MAY provide a single Android sandbox shared by all

            
                applications using the alternate runtime</li>

            
            <li>Alternate runtimes and installed applications using an alternate runtime

            
                MUST NOT reuse the sandbox of any other app installed on the device, except

            
                through the standard Android mechanisms of shared user ID and signing

            
                certificate</li>

            
            <li>Alternate runtimes MUST NOT launch with, grant, or be granted access to

            
                the sandboxes corresponding to other Android applications</li>

            
            </ul>

            
            <p>Alternate runtimes MUST NOT be launched with, be granted, or grant to other

            
               applications any privileges of the superuser (root), or of any other user ID.</p>

            
            <p>The .apk files of alternate runtimes MAY be included in the system image of

            
               a device implementation, but MUST be signed with a key distinct

            
               from the key used to sign other applications included with the device

            
               implementation.</p>

            
            <p>When installing applications, alternate runtimes MUST obtain user consent

            
               for the Android permissions used by the application. That is, if an

            
               application needs to make use of a device resource for which there is a

            
               corresponding Android permission (such as Camera, GPS, etc.), the alternate

            
               runtime MUST inform the user that the application will be able to access

            
               that resource. If the runtime environment does not record application

            
               capabilities in this manner, the runtime environment MUST list all

            
               permissions held by the runtime itself when installing any application

            
               using that runtime.</p>


            <a name="section-9.5"></a><h3>9.5. Multi-User Support </h3>

            
            <p>Android 4.2 includes support for multiple users and provides support for full user isolation

            
            [<a href="#resources70">Resources, 70</a>].</p>

            
            <p>Device implementations MUST meet these requirements related to multi-user support[<a href="#resources71">Resources, 71</a>]:</p>

            
            <ul>

            
            <li>As the behavior of the telephony APIs on devices with multiple users is currently undefined, device implementations that

            
            declare android.hardware.telephony MUST NOT enable multi-user support. </li>

            
            <li>Device implementations MUST, for each user, implement a security model consistent with the Android platform security model

            
            as defined in Security and Permissions reference document in the APIs [Resources, 54]</li>

            
            </ul>

            
            </p>


            <p>Each user instance on an Android device MUST have separate and isolated external storage directories. Device implementations MAY store multiple users' data on the same volume or filesystem.

            
            However, the device implementation MUST ensure that applications owned by and running on behalf a given user cannot list, read, or write to data owned by any other user.

            
            Note that removable media, such as SD card slots, can allow one user to access another's data by means of a host PC. For this reason, device implementations that use removable media for the

            
            external storage APIs MUST encrypt the contents of the SD card if multi-user is enabled using a key stored only on non-removable media accessible only to the system. As this will make the

            
            media unreadable by a host PC, device implementations will be required to switch to MTP or a similar system to provide host PCs with access to the current user's data. Accordingly, device

            
            implementations MAY but SHOULD NOT enable multi-user if they use removable media [<a href="#resources72">Resources, 72</a>] for primary external storage. The upstream Android open-source

            
            project includes an implementation that uses internal device storage for application external storage APIs; device implementations SHOULD use this configuration and software implementation.

            
            Device implementations that include multiple external storage paths MUST NOT allow Android applications to write to the secondary external storage</p>


            <a name="section-9.6"></a><h3>9.6. Premium SMS Warning</h3>

            
            <p>Android 4.2 includes support for warning users for any outgoing premium SMS message. Premium SMS messages are text messages sent to a service registered with a carrier that may incur a charge to the user.

            
            Device implementations that declare support for <code>android.hardware.telephony</code> MUST warn users before sending a SMS message to numbers identified by regular expressions defined in <code>/data/misc/sms/codes.xml</code> file in the device.

            
            The upstream Android open-source project provides an implementation that satisfies this requirement.

            
            </p>


            <a name="section-10"></a><h2>10. Software Compatibility Testing</h2>

            
            <p>Device implementations MUST pass all tests described in this section.</p>

            
            <p>However, note that no software test package is fully comprehensive. For

            
            this reason, device implementers are very strongly encouraged to make the

            
            minimum number of changes as possible to the reference and preferred

            
            implementation of Android 4.2 available from the Android Open Source Project.

            
            This will minimize the risk of introducing bugs that create incompatibilities

            
            requiring rework and potential device updates.</p>

            
            <a name="section-10.1"></a><h3>10.1. Compatibility Test Suite</h3>

            
            <p>Device implementations MUST pass the Android Compatibility Test Suite (CTS)

            
            [<a href="#resources02">Resources, 2</a>] available from the Android Open Source

            
            Project, using the final shipping software on the device. Additionally, device

            
            implementers SHOULD use the reference implementation in the Android Open

            
            Source tree as much as possible, and MUST ensure compatibility in cases of

            
            ambiguity in CTS and for any reimplementations of parts of the reference

            
            source code.</p>

            
            <p>The CTS is designed to be run on an actual device. Like any software, the

            
            CTS may itself contain bugs.  The CTS will be versioned independently of this

            
            Compatibility Definition, and multiple revisions of the CTS may be released

            
            for Android 4.2. Device implementations MUST pass the latest CTS version

            
            available at the time the device software is completed.</p>

            
            <a name="section-10.2"></a><h3>10.2. CTS Verifier</h3>

            
            <p>Device implementations MUST correctly execute all applicable cases in the

            
            CTS Verifier. The CTS Verifier is included with the Compatibility Test Suite,

            
            and is intended to be run by a human operator to test functionality that

            
            cannot be tested by an automated system, such as correct functioning of a

            
            camera and sensors.</p>

            
            <p>The CTS Verifier has tests for many kinds of hardware, including some

            
            hardware that is optional. Device implementations MUST pass all tests for

            
            hardware which they possess; for instance, if a device possesses an

            
            accelerometer, it MUST correctly execute the Accelerometer test case in the

            
            CTS Verifier. Test cases for features noted as optional by this Compatibility

            
            Definition Document MAY be skipped or omitted.</p>

            
            <p>Every device and every build MUST correctly run the CTS Verifier, as noted

            
            above. However, since many builds are very similar, device implementers are

            
            not expected to explicitly run the CTS Verifier on builds that differ only in

            
            trivial ways. Specifically, device implementations that differ from an

            
            implementation that has passed the CTS Verfier only by the set of included

            
            locales, branding, etc. MAY omit the CTS Verifier test.</p>

            
            <a name="section-10.3"></a><h3>10.3. Reference Applications</h3>

            
            <p>Device implementers MUST test implementation compatibility using the

            
            following open source applications:</p>

            
            <ul>

            
            <li>The "Apps for Android" applications [<a href="#resources55">Resources, 55</a>]</li>

            
            <li>Replica Island (available in Android Market)</li>

            
            </ul>

            
            <p>Each app above MUST launch and behave correctly on the implementation, for

            
            the implementation to be considered compatible.</p>


            <a name="section-11"></a><h2>11. Updatable Software</h2>

            
            <p>Device implementations MUST include a mechanism to replace the entirety of

            
            the system software. The mechanism need not perform "live" upgrades - that

            
            is, a device restart MAY be required.</p>

            
            <p>Any method can be used, provided that it can replace the entirety of the

            
            software preinstalled on the device. For instance, any of the following

            
            approaches will satisfy this requirement:</p>

            
            <ul>

            
            <li>Over-the-air (OTA) downloads with offline update via reboot</li>

            
            <li>"Tethered" updates over USB from a host PC</li>

            
            <li>"Offline" updates via a reboot and update from a file on removable

            
            storage</li>

            
            </ul>

            
            <p>The update mechanism used MUST support updates without wiping user data.

            
            That is, the update mechanism MUST preserve application private data

            
            and application shared data. Note that the upstream Android software includes

            
            an update mechanism that satisfies this requirement.</p>

            
            <p>If an error is found in a device implementation after it has been released

            
            but within its reasonable product lifetime that is determined in consultation

            
            with the Android Compatibility Team to affect the compatibility of third-party

            
            applications, the device implementer MUST correct the error via a software

            
            update available that can be applied per the mechanism just described.</p>


            <a name="section-12"></a><h2>12. Contact Us</h2>

            
            <p>You can contact the document authors at <a

            
            href="mailto:compatibility@android.com">compatibility@android.com</a> for

            
            clarifications and to bring up any issues that you think the document does not

            
            cover.</p>


            <div style="page-break-before: always;"></div>


            <a name="appendix-A"></a><h2>Appendix A - Bluetooth Test Procedure</h2>

            
            <p>The Compatibility Test Suite includes cases that cover basic operation of

            
            the Android RFCOMM Bluetooth API. However, since Bluetooth is a communications

            
            protocol between devices, it cannot be fully tested by unit tests running on a

            
            single device. Consequently, device implementations MUST also pass the

            
            human-operated Bluetooth test procedure described below.</p>

            
            <p>The test procedure is based on the BluetoothChat sample app included in the

            
            Android open source project tree. The procedure requires two devices:</p>

            
            <ul>

            
            <li>a candidate device implementation running the software build to be tested</li>

            
            <li>a separate device implementation already known to be compatible, and of a

            
                model from the device implementation being tested - that is, a "known

            
                good" device implementation</li>

            
            </ul>

            
            <p>The test procedure below refers to these devices as the "candidate" and "known

            
            good" devices, respectively.</p>

            
            <h3>Setup and Installation</h3>

            
            <ol>

            
            <li>Build BluetoothChat.apk via 'make samples' from an Android source code tree</li>

            
            <li>Install BluetoothChat.apk on the known-good device</li>

            
            <li>Install BluetoothChat.apk on the candidate device</li>

            
            </ol>

            
            <h3>Test Bluetooth Control by Apps</h3>

            
            <ol>

            
            <li>Launch BluetoothChat on the candidate device, while Bluetooth is disabled</li>

            
            <li>Verify that the candidate device either turns on Bluetooth, or prompts the user with a dialog to turn on Bluetooth</li>

            
            </ol>

            
            <h3>Test Pairing and Communication</h3>

            
            <ol>

            
            <li>Launch the Bluetooth Chat app on both devices</li>

            
            <li>Make the known-good device discoverable from within BluetoothChat (using the Menu)</li>

            
            <li>On the candidate device, scan for Bluetooth devices from within BluetoothChat (using the Menu) and pair with the known-good device</li>

            
            <li>Send 10 or more messages from each device, and verify that the other device receives them correctly</li>

            
            <li>Close the BluetoothChat app on both devices by pressing <b>Home</b></li>

            
            <li>Unpair each device from the other, using the device Settings app</li>

            
            </ol>

            
            <h3>Test Pairing and Communication in the Reverse Direction</h3>

            
            <ol>

            
            <li>Launch the Bluetooth Chat app on both devices.</li>

            
            <li>Make the candidate device discoverable from within BluetoothChat (using the Menu).</li>

            
            <li>On the known-good device, scan for Bluetooth devices from within BluetoothChat (using the Menu) and pair with the candidate device.</li>

            
            <li>Send 10 or messages from each device, and verify that the other device receives them correctly.</li>

            
            <li>Close the Bluetooth Chat app on both devices by pressing Back repeatedly to get to the Launcher.</li>

            
            </ol>

            
            <h3>Test Re-Launches</h3>

            
            <ol>

            
            <li>Re-launch the Bluetooth Chat app on both devices.</li>

            
            <li>Send 10 or messages from each device, and verify that the other device receives them correctly.</li>

            
            </ol>

            
            <p>Note: the above tests have some cases which end a test section by using

            
            Home, and some using Back. These tests are not redundant and are not optional:

            
            the objective is to verify that the Bluetooth API and stack works correctly

            
            both when Activities are explicitly terminated (via the user pressing Back,

            
            which calls finish()), and implicitly sent to background (via the user

            
            pressing Home.) Each test sequence MUST be performed as described.</p>

            
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