Does BroadcastReceiver.onReceive always run in the UI thread?

Question

In my App, I create a custom BroadcastReceiver and register it to my Context manually via Context.registerReceiver. I also have an AsyncTask<

Answer 1

Does BroadcastReceiver.onReceive always run in the UI thread?

Usually, it all depends how you register it.

If you register your BroadcastReceiver using:

registerReceiver(BroadcastReceiver receiver, IntentFilter filter)

It will run in the main activity thread(aka UI thread).

If you register your BroadcastReceiver using a valid Handler running on a different thread:

registerReceiver (BroadcastReceiver receiver, IntentFilter filter, String broadcastPermission, Handler scheduler)

It will run in the context of your Handler

For example:

HandlerThread handlerThread = new HandlerThread("ht");
handlerThread.start();
Looper looper = handlerThread.getLooper();
Handler handler = new Handler(looper);
context.registerReceiver(receiver, filter, null, handler); // Will not run on main thread

Details here & here.