Eventbus: Remove sticky event after consuming

Question

I use firebase to send notification. When the app is in foreground, the notification is received by the class that extends FirebaseMessagingService. So in onMessageReceived, I do this:

EventBus.getDefault().postSticky(new NotificationEvent(body, title, url));

I have two activities that listeners for this event. Activity A and Activity B.

In both activities, I do this:

@Subscribe(sticky = true, threadMode = ThreadMode.MAIN)
    public void consumeNotification(NotificationEvent event) {
        //Consume event
    }

    @Override
    public void onStart() {
        super.onStart();
        EventBus.getDefault().register(this);
        Log.d(TAG, "onStart called");
    }

    @Override
    public void onStop() {
        NotificationEvent event = EventBus.getDefault().getStickyEvent(NotificationEvent.class);
        if (event != null) {
            EventBus.getDefault().removeStickyEvent(event);
        }
        EventBus.getDefault().unregister(this);
        super.onStop();
        Log.d(TAG, "onStop called");
    }

Now, there is a button in Activity A that launches Activity B.

If activity A is visible on the screen, and I receive the notification (which triggers the event), the event is consumed that first time.

So when I click the button to launch Activity B (onStop is called on Activity A), but surprisingly the event is received again in Activity B when it was supposed to have removed when onStop was called in Activity A.

Also, if Activity B is visible on the screen and I receive the notification (which triggers the event), the event is also consumed that first time.

But when I clicked the physical back button to go back to Activity A, the event is received again in Activity A when it's supposed to have been removed.

Please, what's supposed to be the cause of this and how can it be fixed?

NOTE: I chose to use stick event because If I use non-sticky event, the event is not delivered when the screen has deemed off on either of the activities.

Answer 1

Look like you needed to call EventBus.getDefault().removeStickyEvent(event); inside consumeNotification(NotificationEvent event) and leave EventBus.getDefault().unregister(this); in onStop()