How to know when my app has been killed?

I have found one way to do this…..

1. Make one service like this

   public class OnClearFromRecentService extends Service {
   
       @Override
       public IBinder onBind(Intent intent) {
           return null;
       }
   
       @Override
       public int onStartCommand(Intent intent, int flags, int startId) {
           Log.d("ClearFromRecentService", "Service Started");
           return START_NOT_STICKY;
       }
   
       @Override
       public void onDestroy() {
           super.onDestroy();
           Log.d("ClearFromRecentService", "Service Destroyed");
       }
   
       @Override
       public void onTaskRemoved(Intent rootIntent) {
           Log.e("ClearFromRecentService", "END");
           //Code here
           stopSelf();
       }
   }
   

2. Register this service in Manifest.xml like this

   <service android:name="com.example.OnClearFromRecentService" android:stopWithTask="false" />
   

3. Then start this service on your splash activity

   startService(new Intent(getBaseContext(), OnClearFromRecentService.class));
   

And now whenever you will clear your app from android recent Then this method onTaskRemoved() will execute.

NOTE: In Android O+ this solution only works when the app is full-time in foreground. After more than 1 minute with the app in background, the OnClearFromRecentService (and all other Services running) will be automatically force-killed by the system so the onTaskRemoved() will not be executed.