how can I notify a running activity from a broadcast receiver?
I have an activity, it needs to response to a broadcast event. Since an activity开发者_Go百科 can not be a broadcast receiver at the same time, I made a broadcast receiver.
My question is: how can I notify the activity from the broadcast receiver? I believe this is a common situation, so is there a design pattern for this?
The broadcast is the notification. :) If you want to say, start an activity or a service, etc., based on a received broadcast then you need a standalone broadcast receiver and you put that in your manifest file. However, if you want your activity itself to respond to broadcasts then you create an instance of a broadcast receiver in your activity and register it there.
The pattern I use is:
public class MyActivity extends Activity {
private BroadcastReceiver receiver = new BroadcastReceiver() {
@Override
public void onReceive(...) {
...
}
});
public void onResume() {
super.onResume();
IntentFilter filter = new IntentFilter();
filter.addAction(BROADCAST_ACTION);
this.registerReceiver(this.receiver, filter);
}
public void onPause() {
super.onPause();
this.unregisterReceiver(this.receiver);
}
}
So, this way the receiver is instantiated when the class is created (could also do in onCreate). Then in the onResume/onPause I handle registering and unregistering the receiver. Then in the reciever's onReceive
method I do whatever is necessary to make the activity react the way I want to when it receives the broadcast.
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