Fragment 2 fragment communicating

Question

Why i should use the Communicating with Other Fragments pattern when I could simply use

((MyActivity)getActivity()).doFoo();

In my Fragmen

Answer 1

Communicating between fragments should be only through activity. ((MyActivity)getActivity()).doFoo() - will call a method in activity and then update the other fragment

Fragment should be control only by the activity. Say.. if an fragment has a direct way to communicate with the other fragment , then there are possible that an fragment can be detached from other fragment without the activity aware.