How to get notified when the application is closed in Android

Question

I want to show up a Notification when my app is removed from the recent apps list.

I\'ve tried putting code for that in onStop() and

Answer 1

This answer is outdated and most likely will not work on devices with API level 26+ because of the background service limitations introduced in Oreo.

Original answer:

When you swipe an app out of Recents, its task get killed instantly. No lifecycle methods will be called.

To get notified when this happens, you could start a sticky Service and override its onTaskRemoved() method.

From the documentation of onTaskRemoved():

This is called if the service is currently running and the user has removed a task that comes from the service's application.

For example:

public class StickyService extends Service {
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        return START_STICKY;
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onTaskRemoved(Intent rootIntent) {
        Log.d(getClass().getName(), "App just got removed from Recents!");
    }
}

Registering it in AndroidManifest.xml:

<service android:name=".StickyService" />

And starting it (e.g. in onCreate()):

Intent stickyService = new Intent(this, StickyService.class);
startService(stickyService);