Why would LocalBroadcastManager not work instead of Context.registerReceiver?

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);

I've never used LocalBroadcastManager, but it sounds like you have to register your receiver on there (i.e. lbm.registerReceiver(...), not mycontext.registerReceiver(...)). Are you doing that?

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.

The Context class is not related to threads. In fact, both Service and Activity are (indirect) subclasses of Context -- so they're their own Contexts!
^{_{That's why you can use "this" as a Context.}}

But regardless of which context you send into LocalBroadcastManager.getInstance(), you should be getting the exact same LBM instance out. I can't think of any reason that you wouldn't -- except if you're running the Activity and Service in different processes?

check out if your Service and Activity are run in different process, LocalBroadcastManager can't apply in different process.(you should see it in AndroidManifest.xml file)