Weird "Receiver not registered" exception

Question

In onResume() I do:

registerReceiver(timeTickReceiver, new IntentFilter(Intent.ACTION_TIME_TICK)); 

and in onPause():

unregisterReceiver(timeTickReceiver); 

I see "java.lang.IllegalArgumentException: Receiver not registered" reports in Android Developer Console (there are only 2 reports and my app has thousands of users). The exception is triggered by unregisterReceiver(). What can be happening? I don't feel very confident to just surround it with try-catch.

Answer 1

We've seen this error when doing a long press on a particular screen, and then immediately doing two orientation changes (e.g. turning the device upside down).

The API docs for unregisterReceiver says:

Unregister a previously registered BroadcastReceiver.

It doesn't say explicitly, but as you've seen, you hit IllegalArgumentException: Receiver not registered if it isn't already registered.

The workaround I'm using is to store my Receiver as a member field, and have it set to null whenever it is not registered, i.e. I initialize it to null, and then only set it when I register it. This might not be perfect, but it does solve my crashes!

private Receiver mReceiver = null; 

From my onServiceConnected:

sLog.debug("Registering receiver"); mReceiver = new Receiver(); registerReceiver(mReceiver, filter); 

From my onServiceDisconnected:

if (mReceiver == null) {   sLog.info("Do not unregister receiver as it was never registered"); } else {   sLog.debug("Unregister receiver");   unregisterReceiver(mReceiver);   mReceiver = null; } 

Answer 2

A broadcast receiver should be unregister in the onPause() lifecycle method

protected void onPause() {     this.unregisterReceiver(reciever);     super.onPause(); }