使用Guava Eventbus时出现的线程问题和注意事项

Question

Can someone please mention - and explain if possible - the issues related to threads that I need to consider when using guava eventbus ? When I subscribe an android Activity and annotate one of its methods with (@Subscribe), and then post an event from another thread, I got an exception that the event didn't got dispatched.

(I know I need to be on the UI thread to update the UI, that's not what I'm talking about. The event isn't event dispatched !)

EDIT: Here is an example :

post:(This runs in a networking thread)

eventBus.post(new EventShowToast("According to alarm \'" + alarm.getName() + "\', profile \'" + profile.getName() + "\' is run."));

subscribe:(a method in an activity, the activity register itself in onResume(...) )

@Subscribe
    @AllowConcurrentEvents
    public void showToast(EventShowToast event) {
        showToast(event.getMsg());
    }

Answer 1

Are you registering the annotated class with the event bus.

eventBus.register(annotatedClassInstance);

Event Bus Explained

Answer 2

You can only toast from a UI thread. EventBus catches all exceptions and then throws it's own "Could not dispatch event" exception, which is why it is hard to see what the true error was.

The solution to your problem can be found at Toast from a Non-UI thread