3.8. User Interface Compatibility

3.8.1. Launcher (Home Screen)

Android includes a launcher application (home screen) and support for third-party applications to replace the device launcher (home screen).

If device implementations allow third-party applications to replace the device home screen, they:

  • [C-1-1] MUST declare the platform feature android.software.home_screen.
  • [C-1-2] MUST return the AdaptiveIconDrawable object when the third-party application use <adaptive-icon> tag to provide their icon, and the PackageManager methods to retrieve icons are called.

If device implementations include a default launcher that supports in-app pinning of shortcuts, they:

Conversely, if device implementations do not support in-app pinning of shortcuts, they:

If device implementations implement a default launcher that provides quick access to the additional shortcuts provided by third-party apps through the ShortcutManager API, they:

  • [C-4-1] MUST support all documented shortcut features (e.g. static and dynamic shortcuts, pinning shortcuts) and fully implement the APIs of the ShortcutManager API class.

If device implementations include a default launcher app that shows badges for the app icons, they:

  • [C-5-1] MUST respect the NotificationChannel.setShowBadge() API method. In other words, show a visual affordance associated with the app icon if the value is set as true, and do not show any app icon badging scheme when all of the app's notification channels have set the value as false.
  • MAY override the app icon badges with their proprietary badging scheme when third-party applications indicate support of the proprietary badging scheme through the use of proprietary APIs, but SHOULD use the resources and values provided through the notification badges APIs described in the SDK , such as the Notification.Builder.setNumber() and the Notification.Builder.setBadgeIconType() API.

3.8.2. Widgets

Android supports third-party app widgets by defining a component type and corresponding API and lifecycle that allows applications to expose an “AppWidget” to the end user.

If device implementations support third-party app widgets, they:

  • [C-1-1] MUST declare support for platform feature android.software.app_widgets.
  • [C-1-2] MUST include built-in support for AppWidgets and expose user interface affordances to add, configure, view, and remove AppWidgets directly within the Launcher.
  • [C-1-3] MUST be capable of rendering widgets that are 4 x 4 in the standard grid size. See the App Widget DesignGuidelines in the Android SDK documentation for details.
  • MAY support application widgets on the lock screen.

If device implementations support third-party app widgets and in-app pinning of shortcuts, they:

3.8.3. Notifications

Android includes Notification and NotificationManager APIs that allow third-party app developers to notify users of notable events and attract users' attention using the hardware components (e.g. sound, vibration and light) and software features (e.g. notification shade, system bar) of the device. Presentation of Notifications

If device implementations allow third-party apps to notify users of notable events, they:

  • [C-1-1] 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. This behavior is further detailed in section 7.
  • [C-1-2] MUST correctly render all resources (icons, animation files, etc.) provided for in the APIs, or in the Status/System Bar icon style guide, although they MAY provide an alternative user experience for notifications than that provided by the reference Android Open Source implementation.
  • [C-1-3] MUST honor and implement properly the behaviors described for the APIs to update, remove and group notifications.
  • [C-1-4] MUST provide the full behavior of the NotificationChannel API documented in the SDK.
  • [C-1-5] MUST provide a user affordance to block and modify a certain third-party app's notification per each channel and app package level.
  • [C-1-6] MUST also provide a user affordance to display deleted notification channels.
  • [C-1-7] MUST correctly render all resources (images, stickers, icons, etc.) provided through Notification.MessagingStyle alongside the notification text without additional user interaction. For example, MUST show all resources including icons provided through android.app.Person in a group conversation that is set through setGroupConversation.
  • [C-SR] Are STRONGLY RECOMMENDED to automatically surface a user affordance to block a certain third-party app's notification per each channel and app package level after the user dismisses that notification multiple times.
  • SHOULD support rich notifications.
  • SHOULD present some higher priority notifications as heads-up notifications.
  • SHOULD have a user affordance to snooze notifications.
  • MAY only manage the visibility and timing of when third-party apps can notify users of notable events to mitigate safety issues such as driver distraction.

Android 11 introduces support for conversation notifications, which are notifications that use MessagingStyle and provides a published People Shortcut ID.

Device implementations:

  • [C-SR] Are STRONGLY RECOMMENDED to group and display conversation notifications ahead of non conversation notifications with the exception of ongoing foreground service notifications and importance:high notifications.

If device implementations support conversation notifications and the app provides the required data for bubbles, they:

  • [C-SR] Are STRONGLY RECOMMENDED to display this conversation as a bubble. The AOSP implementation meets these requirements with the default System UI, Settings, and Launcher.

If device implementations support rich notifications, they:

  • [C-2-1] MUST use the exact resources as provided through the Notification.Style API class and its subclasses for the presented resource elements.
  • SHOULD present each and every resource element (e.g. icon, title and summary text) defined in the Notification.Style API class and its subclasses.

If device implementations support heads-up notifications: they:

  • [C-3-1] MUST use the heads-up notification view and resources as described in the Notification.Builder API class when heads-up notifications are presented.
  • [C-3-2] MUST display the actions provided through Notification.Builder.addAction() together with the notification content without additional user interaction as described in the SDK. Notification Listener Service

Android includes the NotificationListenerService APIs that allow apps (once explicitly enabled by the user) to receive a copy of all notifications as they are posted or updated.

Device implementations:

If device implementations have a user affordance to snooze notifications, they:

  • [C-1-1] MUST reflect the snoozed notification status properly through the standard APIs such as NotificationListenerService.getSnoozedNotifications().
  • [C-1-2] MUST make this user affordance available to snooze notifications from each installed third-party app's, unless they are from persistent/foreground services. DND (Do not Disturb)

If device implementations support the DND feature, they:

3.8.4. Search

Android includes APIs 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.

  • Android device implementations SHOULD include global search, a single, shared, system-wide search user interface capable of real-time suggestions in response to user input.

If device implementations implement the global search interface, they:

  • [C-1-1] 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 the global search:

  • The default behavior SHOULD be to display web search engine results and suggestions.

Android also includes the Assist APIs to allow applications to elect how much information of the current context is shared with the assistant on the device.

If device implementations support the Assist action, they:

  • [C-2-1] MUST indicate clearly to the end user when the context is shared, by either:
    • Each time the assist app accesses the context, displaying a white light around the edges of the screen that meet or exceed the duration and brightness of the Android Open Source Project implementation.
    • For the preinstalled assist app, providing a user affordance less than two navigations away from the default voice input and assistant app settings menu, and only sharing the context when the assist app is explicitly invoked by the user through a hotword or assist navigation key input.
  • [C-2-2] The designated interaction to launch the assist app as described in section 7.2.3 MUST launch the user-selected assist app, in other words the app that implements VoiceInteractionService, or an activity handling the ACTION_ASSIST intent.

3.8.5. Alerts and Toasts

Applications can use the Toast API to display short non-modal strings to the end user that disappear after a brief period of time, and use the TYPE_APPLICATION_OVERLAY window type API to display alert windows as an overlay over other apps.

If device implementations include a screen or video output, they:

  • [C-1-1] MUST provide a user affordance to block an app from displaying alert windows that use the TYPE_APPLICATION_OVERLAY . The AOSP implementation meets this requirement by having controls in the notification shade.

  • [C-1-2] MUST honor the Toast API and display Toasts from applications to end users in some highly visible manner.

3.8.6. Themes

Android provides “themes” as a mechanism for applications to apply styles across an entire Activity or application.

Android includes a “Holo” and “Material” theme family 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.

If device implementations include a screen or video output, they:

  • [C-1-1] MUST NOT alter any of the Holo theme attributes exposed to applications.
  • [C-1-2] MUST support the “Material” theme family and MUST NOT alter any of the Material theme attributes or their assets exposed to applications.
  • [C-1-3] MUST use the Roboto version 2.x fonts as the out-of-box Sans-serif font family for languages that Roboto supports.

Android also includes a “Device Default” theme family 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.

Android supports a variant theme with translucent system bars, which allows application developers to fill the area behind the status and navigation bar with their app content. To enable a consistent developer experience in this configuration, it is important the status bar icon style is maintained across different device implementations.

If device implementations include a system status bar, they:

  • [C-2-1] MUST use white for system status icons (such as signal strength and battery level) and notifications issued by the system, unless the icon is indicating a problematic status or an app requests a light status bar using the SYSTEM_UI_FLAG_LIGHT_STATUS_BAR flag.
  • [C-2-2] Android device implementations MUST change the color of the system status icons to black (for details, refer to R.style) when an app requests a light status bar.

3.8.7. Live Wallpapers

Android defines a component type and corresponding API and lifecycle that allows applications to expose one or more “Live Wallpapers” to the end user. Live wallpapers are animations, patterns, or similar images with limited input capabilities that display as a wallpaper, behind other applications.

Hardware is considered capable of reliably running live wallpapers if it can run all live wallpapers, with no limitations on functionality, at a reasonable frame rate with no adverse effects 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 OpenGL 2.0 or 3.x 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.

  • Device implementations capable of running live wallpapers reliably as described above SHOULD implement live wallpapers.

If device implementations implement live wallpapers, they:

  • [C-1-1] MUST report the platform feature flag android.software.live_wallpaper.

3.8.8. Activity Switching

The upstream Android source code includes the overview screen, a system-level user interface for task switching and displaying recently accessed activities and tasks using a thumbnail image of the application’s graphical state at the moment the user last left the application.

Device implementations including the recents function navigation key as detailed in section 7.2.3 MAY alter the interface.

If device implementations including the recents function navigation key as detailed in section 7.2.3 alter the interface, they:

  • [C-1-1] MUST support at least up to 7 displayed activities.
  • SHOULD at least display the title of 4 activities at a time.
  • [C-1-2] MUST implement the screen pinning behavior and provide the user with a settings menu to toggle the feature.
  • SHOULD display highlight color, icon, screen title in recents.
  • SHOULD display a closing affordance (“x”) but MAY delay this until user interacts with screens.
  • SHOULD implement a shortcut to switch easily to the previous activity.
  • SHOULD trigger the fast-switch action between the two most recently used apps, when the recents function key is tapped twice.
  • SHOULD trigger the split-screen multiwindow-mode, if supported, when the recents functions key is long pressed.
  • MAY display affiliated recents as a group that moves together.
  • [SR] Are STRONGLY RECOMMENDED to use the upstream Android user interface (or a similar thumbnail-based interface) for the overview screen.

3.8.9. Input Management

Android includes support for Input Management and support for third-party input method editors.

If device implementations allow users to use third-party input methods on the device, they:

  • [C-1-1] MUST declare the platform feature android.software.input_methods and support IME APIs as defined in the Android SDK documentation.

3.8.10. Lock Screen Media Control

The Remote Control Client API is deprecated from Android 5.0 in favor of the Media Notification Template that allows media applications to integrate with playback controls that are displayed on the lock screen.

3.8.11. Screen savers (previously Dreams)

See section for settings intent to congfigure screen savers.

3.8.12. Location

If device implementations include a hardware sensor (e.g. GPS) that is capable of providing the location coordinates, they

3.8.13. Unicode and Font

Android includes support for the emoji characters defined in Unicode 10.0.

If device implementations include a screen or video output, they:

  • [C-1-1] MUST be capable of rendering these emoji characters in color glyph.
  • [C-1-2] MUST include support for:
    • Roboto 2 font with different weights—sans-serif-thin, sans-serif-light, sans-serif-medium, sans-serif-black, sans-serif-condensed, sans-serif-condensed-light for the languages available on the device.
    • Full Unicode 7.0 coverage of Latin, Greek, and Cyrillic, including the Latin Extended A, B, C, and D ranges, and all glyphs in the currency symbols block of Unicode 7.0.
  • SHOULD support the skin tone and diverse family emojis as specified in the Unicode Technical Report #51.

If device implementations include an IME, they:

  • SHOULD provide an input method to the user for these emoji characters.

Android includes support to render Myanmar fonts. Myanmar has several non-Unicode compliant fonts, commonly known as “Zawgyi,” for rendering Myanmar languages.

If device implementations include support for Burmese, they:

* [C-2-1] MUST render text with Unicode compliant font as default;
  non-Unicode compliant font MUST NOT be set as default font unless the user
  chooses it in the language picker.
* [C-2-2] MUST support a Unicode font and a non-Unicode compliant font if a
  non-Unicode compliant font is supported on the device.  Non-Unicode
  compliant font MUST NOT remove or overwrite the Unicode font.
* [C-2-3] MUST render text with non-Unicode compliant font ONLY IF a
  language code with [script code Qaag](
  http://unicode.org/reports/tr35/#unicode_script_subtag_validity) is
  specified (e.g. my-Qaag). No other ISO language or region codes (whether
  assigned, unassigned, or reserved) can be used to refer to non-Unicode
  compliant font for Myanmar. App developers and web page authors can
  specify my-Qaag as the designated language code as they would for any
  other language.

3.8.14. Multi-windows

If device implementations have the capability to display multiple activities at the same time, they:

  • [C-1-1] MUST implement such multi-window mode(s) in accordance with the application behaviors and APIs described in the Android SDK multi-window mode support documentation and meet the following requirements:
  • [C-1-2] MUST honor android:resizeableActivity that is set by an app in the AndroidManifest.xml file as described in this SDK.
  • [C-1-3] MUST NOT offer split-screen or freeform mode if the screen height is less than 440 dp and the screen width is less than 440 dp.
  • [C-1-4] An activity MUST NOT be resized to a size smaller than 220dp in multi-window modes other than Picture-in-Picture.
  • Device implementations with screen size xlarge SHOULD support freeform mode.

If device implementations support multi-window mode(s), and the split screen mode, they:

  • [C-2-1] MUST preload a resizeable launcher as the default.
  • [C-2-2] MUST crop the docked activity of a split-screen multi-window but SHOULD show some content of it, if the Launcher app is the focused window.
  • [C-2-3] MUST honor the declared AndroidManifestLayout_minWidth and AndroidManifestLayout_minHeight values of the third-party launcher application and not override these values in the course of showing some content of the docked activity.

If device implementations support multi-window mode(s) and Picture-in-Picture multi-window mode, they:

  • [C-3-1] MUST launch activities in picture-in-picture multi-window mode when the app is: * Targeting API level 26 or higher and declares android:supportsPictureInPicture * Targeting API level 25 or lower and declares both android:resizeableActivity and android:supportsPictureInPicture.

  • [C-3-2] MUST expose the actions in their SystemUI as specified by the current PIP activity through the setActions() API.

  • [C-3-3] MUST support aspect ratios greater than or equal to 1:2.39 and less than or equal to 2.39:1, as specified by the PIP activity through the setAspectRatio() API.

  • [C-3-4] MUST use KeyEvent.KEYCODE_WINDOW to control the PIP window; if PIP mode is not implemented, the key MUST be available to the foreground activity.

  • [C-3-5] MUST provide a user affordance to block an app from displaying in PIP mode; the AOSP implementation meets this requirement by having controls in the notification shade.

  • [C-3-6] MUST allocate the following minimum width and height for the PIP window when an application does not declare any value for AndroidManifestLayout_minWidth and AndroidManifestLayout_minHeight:

    • Devices with the Configuration.uiMode that is set other than UI_MODE_TYPE_TELEVISION MUST allocate a minimum width and height of 108 dp.
    • Devices with the Configuration.uiMode that is set to UI_MODE_TYPE_TELEVISION MUST allocate a minimum width of 240 dp and a minimum height of 135 dp.

3.8.15. Display Cutout

Android supports a Display Cutout as described in the SDK document. The DisplayCutout API defines an area on the edge of the display that may not be functional for an application due to a display cutout or curved display on the edge(s).

If device implementations include display cutout(s), they:

  • [C-1-5] MUST NOT have cutout(s) if the device's aspect ratio is 1.0(1:1).
  • [C-1-2] MUST NOT have more than one cutout per edge.
  • [C-1-3] MUST honor the display cutout flags set by the app through the WindowManager.LayoutParams API as described in the SDK.
  • [C-1-4] MUST report correct values for all cutout metrics defined in the DisplayCutout API.

3.8.16. Device Controls

Android includes ControlsProviderService and Control APIs to allow third-party applications to publish device controls for quick status and action for users.

See Section 2_2_3 for device-specific requirements.