setBroadcast(true) hangs on Android

In order to send broadcast messages we need to call setBroadcast() first. However this method hangs and never returns!

protected void doInBackgroundGuarded(Void... params) {
	UdpSocketClient client = findClient(cId, callback);
	if (client == null) {
		return;
	}

	try {
		client.setBroadcast(flag);
		// **** we never get there!

		callback.invoke();
	} catch (SocketException e) {
		callback.invoke(UdpErrorUtil.getError(null, e.getMessage()));
	}
}

I tested in Android emulator and with a Samsung Galaxy S8. Both running on Android API 28. Any ideas what is going on here?

[shynst]

@nishmeht7: I did fix it 2 years ago (works very well in production code):

It seems we must not call setBroadcast() after the receiving thread was started, since this will result in a deadlock. Therefore I removed automatic start of receive on bind and introduced a new method startReveiving().

See details in my commit above.

[nishmeht7]

@shynst Thank you so much, you’re a life saver!