Why would LocalBroadcastManager not work instead of Context.registerReceiver?

Question

I had to implement a feature to this app which consists of an Activity and a Service working on the background (it implements Service, not IntentService).

I went through a few tutorials on the Internet that are supposed to work, and they all use LocalBroadcastManager, which by the way is the recommended by Android:

If you don't need to send broadcasts across applications, consider using this class with LocalBroadcastManager instead of the more general facilities described below.

I literally lost a day to find out the problem why it wouldn't work for me: it only works if I use Context.sendBroadcast(). and Context.registerReceiver() instead of the LocalBroadcastManager methods.

Now my app is working, but I feel I am going against the best practices, and I don't know why. Any ideas why it could be happening?

EDIT:

After I wrote this question I went further on the problem. LocalBroadcastManager works through a Singleton, as we should call LocalBroadcastManager.getInstance(this).method(). I logged both instances (in the Activity and in the Service) and they have different memory addresses. Now I came to another question, shouldn't a Service have the same Context as the Activity that called it? From this article a Service runs on the Main Thread, hence I'd think the Context would be the same.

Any thoughts on that? (sorry for the long post)

Code samples:

MyService

public class MyService extends Service {

...

// When an event is triggered, sends a broadcast

Intent myIntent = new Intent(MainActivity.MY_INTENT);
myIntent.putExtra("myMsg","msg");
sendBroadcast(myIntent);

// Previously I was trying:
// LocalBroadcastManager.getInstance(getApplicationContext()).sendBroadcast(myIntent);

}

MyActivity

public class MainActivity {

...

private BroadcastReceiver messageReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) { 
            Log.d("onReceive", "received!");
            // TODO something
        }
    };

@Override
protected void onResume() {
    super.onResume();
    registerReceiver(messageReceiver, new IntentFilter(MY_INTENT));
    // Previously I was trying:
    // LocalBroadcastManager.getInstance(getApplicationContext()).registerReceiver(messageReceiver, new IntentFilter(MY_INTENT));
}
}

Answer 1

Declaration:

private BroadcastReceiver receiver;

Initialization:

receiver = new BroadcastReceiver()
{
    @Override
    public void onReceive(Context context, Intent intent)
    {
        //todo
    }
};

Registration:

LocalBroadcastManager.getInstance(context).registerReceiver(receiver, new IntentFilter("RECEIVER_FILTER"));

context can be any type of Context, you can use the application context.

Unregister:

LocalBroadcastManager.getInstance(context).unregisterReceiver(receiver);

Broadcast:

Intent intent = new Intent("RECEIVER_FILTER");
intent.putExtra("EXTRA", someExtra);
LocalBroadcastManager.getInstance(context).sendBroadcast(intent);