Inform Activity from a BroadcastReceiver ONLY if it is in the foreground

Question

Maybe it's easy, but I couldn't really figure this out right so far... I got a BroadcastReceiver waiting to get triggered by the AlarmMangager - this works fine.

Now: because the event, if it occurs, needs to refresh some elements on screen of the main Activity, I would like to send an Intent from that background BroadcastReceiver to my Activity - but only if it is currently in the foreground, aka active.

If it is not running or not visible, I don't care - and the last thing I want to do is start the Activity by my intent! I handle repainting of the views in my onResume() method, so I don't care at all.

Any hints on how to do that? Thanks!

EDIT: my BroadcastReceiver is waiting for alarms that must be notified to the user. So, it must be there and declared in the manifest. The problem is: it will have to decide whether the mentioned Activity is currently up in front or not.

Answer 1

I believe that you're familiar with AlarmManager now (creating a new Alarm, register a receiver...) so I will not talk about that. Just give you a solution for your question.

Instead of registering a BroadcastReceiver in a class file and in manifest, you only create a new BroadcastReceiver in your activity, and then, register it in onResume method, and unregister it in onPause method, sth like this in your activity:

private BroadcastReceiver mIntentReceiver = new BroadcastReceiver() {     @Override     public void onReceive(Context context, Intent intent) {       //do something            } };  @Override public void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.main);      mIntentFilter = new IntentFilter();     mIntentFilter.addAction("your alarm action");     ... }  @Override protected void onResume() { registerReceiver(mIntentReceiver, mIntentFilter);     ... super.onResume(); }  @Override protected void onPause() { unregisterReceiver(mIntentReceiver);     ... super.onPause(); } 

The receiver will only receive the alarm intent when your activity is in foreground :)

(Sorry if my English is not clear)