Android best practices for Fragment to Activity communications

Question

I am new to Android Fragment and trying to learn Fragment to Activity communications. What is the better approach(best practice) in Android for Fragment to Activity communication?

Lets say I have FragmentA and ActivityA. After my screen popups FragmentA, I would like to perform somemethod(probably UI related) in ActivityA

Here are two(pattern) possible Solutions:

1. In FragmentA getActivity and cast the Activity to ActivityA and then call somemethod.
2. In FragmentA create an interface callback and then implement that callback in ActivityA. Then on the callback, call somemethod.

Which pattern is more common/perfer in Android development and why. Or do you have an even better way to communicate from fragment to activity in Android to share with me?

Any comments, opinions, and suggestions is highly appreciated and welcome. ^^ .

Answer 1

The second solution is the preferred one, because it allows your fragment to be more independent of its hosting activity.

If in the future you decide to put your fragment on a different activity, there are no changes needed on the fragment, and you will only need to implement the interface on your activity.

I'll add a third solution which is using an event bus (Otto for instance), which also works, although some might argue that it makes your code a little less readable.