docs/html/work/cosu.jd

page.title=Set up Single-Purpose Devices
page.tags=work, cosu
page.keywords=cosu, work
page.metaDescription=Learn how to develop single-use solutions for Android devices.
page.image=images/work/cards/briefcase_600px.png

@jd:body

<div id="qv-wrapper">
  <div id="qv">
    <h2>In this document</h2>
    <ol>
      <li><a href="#locktask">How to use LockTask mode</a></li>
      <li><a href="#cosu-solutions">Build COSU solutions</a></li>
      <li><a href="#create-dpc">Create your own DPC app</a></li>
    </ol>
  </div>
</div>

<p>
As an IT administrator, you can configure Android 6.0 Marshmallow and later
devices as <em>corporate-owned, single-use (COSU)</em> devices. These are Android
devices used for a single purpose, such as digital signage, ticket printing,
point of sale, or inventory management. To use Android devices as COSU devices,
you need to develop Android apps that your customers can manage.
</p>

<p>
Your customers can configure COSU devices:
</p>
<ul>
<li>
To lock a single application to the screen, and hide the
<strong>Home</strong> and <strong>Recents</strong> buttons to prevent users
from escaping the app.
</li>

<li>
To allow multiple applications to appear on the screen, such as a library kiosk
with a catalog app and web browser.
</li>
</ul>

<h2 id="pinning">
App pinning vs. lock task mode
</h2>

<p>Android 5.0 Lollipop introduced two new ways to configure Android devices
for a single purpose:
</p>

<ul>
<li>
With app pinning, the device user can temporarily pin specific apps to the
screen.
</li>

<li>
With lock task mode, a user can’t escape the app and the Home and Recents
buttons are hidden. Additionally, lock task mode gives the IT administrator
a more robust way to manage COSU devices, as discussed below.
</li>
</ul>

<p>
This graphic compares the features of app pinning and lock task mode:
</p>

<img src="{@docRoot}images/work/cosu-pinning_vs_locktaskmode.png"
width="640" srcset="{@docRoot}images/work/cosu-pinning_vs_locktaskmode.png 1x,
{@docRoot}images/work/cosu-pinning_vs_locktaskmode_2x.png 2x" />

 <p class="img-caption">
   <strong>Figure 1.</strong> Comparing the features of app pinning in Lollipop
   vs. Lock task mode in Marshmallow and later
 </p>

<p>
In Lollipop, you can pin a single application to cover the full screen, but
only apps whitelisted by the device policy controller (DPC) can be locked.
</p>

<h2 id="locktask">
  How to use LockTask mode
</h2>

<p>
  To use LockTask mode, and the APIs that manage COSU devices, there must be
  a device owner application installed on the device. Device owners are a
  type of device policy controller (DPC) that manages the whole device. For
  more information about DPCs, see the
  <a class="external-link" href="https://developers.google.com/android/work/overview">EMM Developer’s Overview</a>.
</p>

<p>
If you’re creating a new COSU app, we recommend you develop it for
Marshmallow or later, which includes the following COSU features:
</p>

<ul>
<li>
Controls system updates
</li>

<li>
Sets status and menu bar visibility
</li>

<li>
Disables screen lock and sleep functions
</li>

<li>
Permits switching between apps while staying in lock task mode
</li>

<li>
Prevents restarting in safe mode
</li>
</ul>

<p class="note">
  <strong>Note:</strong> If you develop COSU features targeted for
  Marshmallow devices, your app can still be compatible with prior
  versions of Android.
</p>

<p>
Additional COSU management features launched with Marshmallow make it easier to
develop and deploy Android devices as a single-use device. If you want to
enforce server-side managed configurations or server-side profile policy controls,
you need to use an EMM or make your application a DPC. Follow the instructions
below as you create your application.
</p>

<h2 id="cosu-solutions">
  Build COSU solutions
</h2>

<p>
  There are two different ways to manage COSU devices:
</p>

<ul>
<li>
<strong>Use a third-party enterprise mobility management (EMM)
solution</strong>: Using an EMM, all you need to do is set up lock task mode.
For instructions, skip to the next section,
<a href="#emm-solutions">Solutions managed by a third-party EMM</a>.
</li>

<li>
<strong>Advanced setup—Create your own DPC app</strong>: This requires
more work and is intended for an advanced developer audience. With this
option, you’ll need to set up the device so that you can manage it, set
up APIs, and set up a DPC app and test it. For instructions, skip to
<a href="#create-dpc">Create your own DPC app</a>.
</li>
</ul>

<h2 id="emm-solutions">
Solutions managed by a third-party EMM
</h2>

<p>
In this section, you’ll need to do a small amount of development to
have your device work with a third-party EMM.
</p>

<h3 id="use-smartlocktask">
Using startLockTask()
</h3>

<p>
If you need to add COSU functionality to an existing app, make sure that
the customer’s EMM supports {@link android.R.attr#lockTaskMode}.
</p>

<ul>
<li>
The device owner must include your app’s package(s) in
{@link android.app.admin.DevicePolicyManager#setLockTaskPackages setLockTaskPackages}</li>
<ul>
<li>
Sets the packages that can enter into lock task mode
</li>
<li>
Needs to be set by the EMM
</li>
<li>
You can call {@link android.app.admin.DevicePolicyManager#isLockTaskPermitted isLockTaskPermitted}
to verify that your package has been whitelisted by
{@link android.app.admin.DevicePolicyManager#setLockTaskPackages setLockTaskPackages}.
</li>
</ul>

<li>
Your activity calls {@link android.app.Activity#startLockTask()}
</li>
<ul>
<li>
Requests to lock the user into the current task
</li>
<li>
Prevents launching other apps, settings, and the <strong>Home</strong>
button
</li>
</ul>

<li>
To exit, your activity must call {@link android.app.Activity#stopLockTask()}
</li>
<ul>
<li>
Can only be called on an activity that’s previously called
 {@link android.app.Activity#startLockTask()}
</li>
<li>
Should be called when the app is user-facing between {@link android.app.Activity#onResume()}
and {@link android.app.Activity#onPause()}
</li>
</ul>
</ul>

<p>
Starting from Marshmallow, if your app is whitelisted by an EMM using {@link 
android.app.admin.DevicePolicyManager#setLockTaskPackages setLockTaskPackages},
your activities can automatically start lock task mode when the app is
launched.
</p>

<h3 id="locktaskmode-attribute">
Set the lockTaskMode attribute
</h3>

<p>
  The {@link android.R.attr#lockTaskMode} attribute allows you to define
  your app’s lock task mode behavior in the AndroidManifest.xml file:
</p>

<ul>
<li>
If you set {@link android.R.attr#lockTaskMode} to <code>if_whitelisted</code>,
you don’t need to call {@link android.app.Activity#startLockTask()}, and the
app automatically enters into lock task mode.
</li>

<li>
System apps and privileged apps can also set {@link android.R.attr#lockTaskMode}
to always. This setting causes tasks (rooted at your activity) to always
launch into lock task mode. Non-privileged apps are treated as normal.
</li>

<li>
The default value of the {@link android.R.attr#lockTaskMode} attribute is
normal. When this attribute is set to normal, tasks don’t launch into 
{@link android.R.attr#lockTaskMode}, unless {@link android.app.Activity#startLockTask()} 
is called. To call {@link android.app.Activity#startLockTask()},
applications still need to be whitelisted using 
{@link android.app.admin.DevicePolicyManager#setLockTaskPackages setLockTaskPackages}, 
otherwise, the user sees a dialog to approve entering pinned mode.
</li>
</ul>
  
<p>To have your activity <em>automatically</em> enter {@link android.R.attr#lockTaskMode},
change the value of this attribute to <code>if_whitelisted</code>.
Doing so causes your app to behave in this manner:
</p>

<ul>
<li>
If your app isn’t whitelisted for {@link android.R.attr#lockTaskMode},
it behaves as normal.
</li>

<li>
If your app is a system or privileged app, and it’s whitelisted,
{@link android.R.attr#lockTaskMode} automatically starts when the app is
launched.
</li>
</ul>

<p>
Example XML as follows:
</p>

 <pre>&lt;activity android:name=".MainActivity" android:lockTaskMode="if_whitelisted"&gt;</pre>

<p>
Given either of these options, you still need to create a mechanism for
calling {@link android.app.Activity#stopLockTask()} so that users can
exit {@link android.R.attr#lockTaskMode}. 
</p>

<h2 id="create-dpc">
  Advanced setup—Create your own DPC app
</h2>

<p>
To manage applications in COSU, you need a DPC running as device
owner to set several policies on the device. 
</p>

<p class="note">
<strong>Note:</strong> This setup is advanced, and requires
a thorough understanding of the EMM concepts described in the
<a class="external-link" href="https://developers.google.com/android/work/prov-devices#implementation_considerations_for_device_owner_mode">EMM developer overview</a>.
For more information about building a DPC, see
<a class="external-link"
href="https://developers.google.com/android/work/prov-devices">Provision Customer Devices</a>.
</p>

<p>
To create a DPC app that can manage COSU device configuration,
the DPC needs to:
</p>

<ol>
<li>
Provision the device into device owner mode. We recommend that
you support provisioning with near field communication (NFC) bump.
For more information, see
<a class="external-link" href="https://developers.google.com/android/work/prov-devices#nfc_method"
>Device Owner Provisioning via NFC</a>.
</li>

<li>
Use the following APIs:
<ul>
<li>
Keep devices from locking with the keyguard using
{@link android.app.admin.DevicePolicyManager#setKeyguardDisabled setKeyguardDisabled()}
</li>

<li>
Disable the status bar using
{@link android.app.admin.DevicePolicyManager#setStatusBarDisabled setStatusBarDisabled()}
</li>

<li>
Keep a device’s screen on while plugged in via
{@link android.provider.Settings.Global#STAY_ON_WHILE_PLUGGED_IN}
</li>

<li>
Set default user restriction for managed configurations via
{@link android.app.admin.DevicePolicyManager#addUserRestriction addUserRestriction()}
</li>

<li>
Set system update policies using
{@link android.app.admin.DevicePolicyManager#setSystemUpdatePolicy setSystemUpdatePolicy()}
</li>

<li>
Ensure your app is launched on reboot by setting it as the default launcher
</li>
</ul>
</li>
</ol>

<p>
Here’s an example of how to implement an activity that starts lock task mode
and implements the relevant COSU device management APIs:
</p>

<pre>
public class CosuActivity extends Activity {

    private ComponentName mAdminComponentName;
    private DevicePolicyManager mDevicePolicyManager;
    private PackageManager mPackageManager;
    private static final String Battery_PLUGGED_ANY = Integer.toString(
            BatteryManager.BATTERY_PLUGGED_AC |
            BatteryManager.BATTERY_PLUGGED_USB |
            BatteryManager.BATTERY_PLUGGED_WIRELESS);

    private static final String DONT_STAY_ON = "0";

    &#64;Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mAdminComponentName = DeviceAdminReceiver.getComponentName(this);
        mDevicePolicyManager = (DevicePolicyManager) getSystemService(
                Context.DEVICE_POLICY_SERVICE);
        mPackageManager = getPackageManager();
        setDefaultCosuPolicies(true);
    }

    &#64;Override
    protected void onStart() {
        super.onStart();

        // start lock task mode if it's not already active
        ActivityManager am = (ActivityManager) getSystemService(
                Context.ACTIVITY_SERVICE);
        // ActivityManager.getLockTaskModeState api is not available in pre-M.
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
            if (!am.isInLockTaskMode()) {
                startLockTask();
            }
        } else {
            if (am.getLockTaskModeState() ==
                    ActivityManager.LOCK_TASK_MODE_NONE) {
                startLockTask();
            }
        }
    }

    private void setDefaultCosuPolicies(boolean active) {
        // set user restrictions
        setUserRestriction(UserManager.DISALLOW_SAFE_BOOT, active);
        setUserRestriction(UserManager.DISALLOW_FACTORY_RESET, active);
        setUserRestriction(UserManager.DISALLOW_ADD_USER, active);
        setUserRestriction(UserManager.DISALLOW_MOUNT_PHYSICAL_MEDIA, active);
        setUserRestriction(UserManager.DISALLOW_ADJUST_VOLUME, active);

        // disable keyguard and status bar
        mDevicePolicyManager.setKeyguardDisabled(mAdminComponentName, active);
        mDevicePolicyManager.setStatusBarDisabled(mAdminComponentName, active);

        // enable STAY_ON_WHILE_PLUGGED_IN
        enableStayOnWhilePluggedIn(active);

        // set System Update policy

        if (active){
            mDevicePolicyManager.setSystemUpdatePolicy(mAdminComponentName,
                    SystemUpdatePolicy.createWindowedInstallPolicy(60,120));
        } else {
            DevicePolicyManager.setSystemUpdatePolicy(mAdminComponentName, null);
        }

        // set this Activity as a lock task package

        mDevicePolicyManager.setLockTaskPackages(mAdminComponentName,
                active ? new String[]{getPackageName()} : new String[]{});

        IntentFilter intentFilter = new IntentFilter(Intent.ACTION_MAIN);
        intentFilter.addCategory(Intent.CATEGORY_HOME);
        intentFilter.addCategory(Intent.CATEGORY_DEFAULT);

        if (active) {
            // set Cosu activity as home intent receiver so that it is started
            // on reboot
            mDevicePolicyManager.addPersistentPreferredActivity(
                    mAdminComponentName, intentFilter, new ComponentName(
                            getPackageName(), CosuActivity.class.getName()));
        } else {
            mDevicePolicyManager.clearPackagePersistentPreferredActivities(
                    mAdminComponentName, getPackageName());
        }
    }

    private void setUserRestriction(String restriction, boolean disallow) {
        if (disallow) {
            mDevicePolicyManager.addUserRestriction(mAdminComponentName,
                    restriction);
        } else {
            mDevicePolicyManager.clearUserRestriction(mAdminComponentName,
                    restriction);
        }
    }

    private void enableStayOnWhilePluggedIn(boolean enabled) {
        if (enabled) {
            mDevicePolicyManager.setGlobalSetting(
                    mAdminComponentName,
                    Settings.Global.STAY_ON_WHILE_PLUGGED_IN,
                    Battery_PLUGGED_ANY);
        } else {
            mDevicePolicyManager.setGlobalSetting(
                    mAdminComponentName,
                    Settings.Global.STAY_ON_WHILE_PLUGGED_IN, DONT_STAY_ON);
        }
    }

    // TODO: Implement the rest of the Activity
}
</pre>


<h2 id="testing-plan">
  Develop a test plan for COSU
</h2>

<p>
  If you’re planning to support a third-party EMM, develop an end-to-end
  testing plan utilizing the EMM’s app. We also provide testing resources,
  which you can use to create your own Test Device Policy Client (Test DPC):
</p>

<ul>
<li>
<a class="external-link" href="https://play.google.com/store/search?q=testdpc">TestDPC on Google Play</a>
</li>
<li>
<a class="external-link" href="https://github.com/googlesamples/android-testdpc/tree/master/app/src/main/java/com/afwsamples/testdpc/cosu">TestDPC for COSU source code on GitHub</a>
</li>
<li>
<a class="external-link" href="https://github.com/googlesamples/android-testdpc">Test Device Policy Control app source code on GitHub</a>
</li>
</ul>