BroadcastReceiver | Android Developers
Base class for code that will receive intents sent by sendBroadcast(). You can either dynamically register an instance of this class with Context.registerReceiver() or statically publish an implementation through the tag in your AndroidManifest.xml. Note: If registering a receiver in your Activity.onResume() implementation, you should unregister it in Activity.onPause(). (You won’t receive intents when paused, and this will cut down on unnecessary system overhead). Do not unregister in Activity.onSaveInstanceState(), because this won’t be called if the user moves back in the history stack.
