How to restart service after the app is killed from recent tasks

Question

I have created a service to fetch current location of the device in periodic intervals. I want the service to run in the background even if the app is cleared from recently

Answer 1

Override onTaskRemoved() in your service and use alarm manager to start the service again. Below is code from our app that does the same and works fine:

@Override
public void onTaskRemoved(Intent rootIntent) {
    super.onTaskRemoved(rootIntent);

    Log.d(TAG, "TASK REMOVED");

    PendingIntent service = PendingIntent.getService(
            getApplicationContext(),
            1001,
            new Intent(getApplicationContext(), MyService.class),
            PendingIntent.FLAG_ONE_SHOT);

    AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
    alarmManager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, 1000, service);
}  

As you may want to send location periodically even in the case if the service gets killed on low memory (or for any reason), I suggest you to handle the uncaughtException to restart it after N seconds. This is how we have done in our app that works perfectly:

private Thread.UncaughtExceptionHandler defaultUEH;
private Thread.UncaughtExceptionHandler uncaughtExceptionHandler = new Thread.UncaughtExceptionHandler() {

    @Override
    public void uncaughtException(Thread thread, Throwable ex) {
        Log.d(TAG, "Uncaught exception start!");
        ex.printStackTrace();

        //Same as done in onTaskRemoved()
        PendingIntent service = PendingIntent.getService(
                getApplicationContext(),
                1001,
                new Intent(getApplicationContext(), MyService.class),
                PendingIntent.FLAG_ONE_SHOT);

        AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
        alarmManager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, 1000, service);
        System.exit(2);
        }
    };

Note: I THINK and I remember I verified it on Kitkat that START_STICKY does not work on Kitkat and higher API levels. Please verify this for yourself.

MORE:
As you do loc sending periodically, you may have to consider the deep sleep mode. To get things work in deep sleep, use WakefulBroadcastReceiver combined with AlarmManager. Take a look at my other post How to use http in deep sleep mode.

UPDATE:
This solution does not work (in fact need not to work) if user "FORCE STOP" the application from Settings. This is good in fact as restarting the service is not a good way if user himself wants to stop application. So, it is fine.