Question

I’ve a problem with an app I’m coding.
I need to receive ACTION_SCREEN_ON, ACTION_SCREEN_OFF and ACTION_USER_PRESENT intents everytime they’re broadcasted, so my app of course stays in background. At the moment my app is made by a settings activity and a service. ScreenReceiver is a BroadcastReceiver that gets the ACTION_SCREEN_* intents, while UnlockReceiver gets the ACTION_USER_PRESENT intent. The service registers and unregisters the receivers:

public class MainService extends Service {
    ScreenReceiver screenReceiver = null;
    UnlockReceiver unlockReceiver = null;

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

    @Override
    public void onStart(Intent intent, int startId) {
        doStart();
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        doStart();

        return START_STICKY;
    }

    public void doStart() {
        if(screenReceiver != null && unlockReceiver != null)
            return;

        IntentFilter filter;

        if(screenReceiver == null) {
            filter = new IntentFilter();
            filter.addAction(Intent.ACTION_SCREEN_ON);
            filter.addAction(Intent.ACTION_SCREEN_OFF);

            screenReceiver = new ScreenReceiver();
            registerReceiver(screenReceiver, filter);
        }

        if(unlockReceiver == null) {
            filter = new IntentFilter();
            filter.addAction(Intent.ACTION_USER_PRESENT);

            unlockReceiver = new UnlockReceiver();
            registerReceiver(unlockReceiver, filter);
        }
    }

    @Override
    public void onDestroy() {
        if(screenReceiver != null)
            unregisterReceiver(screenReceiver);

        if(unlockReceiver != null)
            unregisterReceiver(unlockReceiver);
    }
}  

But sometimes Android kills my service to free some RAM and then restarts it. The time between the kill and the respawn is usually around 5 seconds, but sometimes this can be enought to miss some intents causing problems to the users of my app. Those intents can be registered only trought registerReceiver, so I can’t register them in the manifest. How could I listen to those intents without being killed or missing some?

Thanks!

Answer 1

How could I listen to those intents without being killed or missing some?

You don’t. You rewrite your app to either not use those broadcasts or to be more resilient in the case of missing broadcasts. After all, it is not just “Android kills my service to free some RAM and then restarts it”, but task managers and the like that can get rid of your service.