Interface communication from fragment to activity issue

Question

I\'ve recently tried to use an interface for fragment-activity communication. The idea is that when a button is pressed in a fragment, it retrieves data from an EditText in the

Answer 1

getActivity() but it cannot find the associated method within the fragment

This is because getActivity() returns an Activity, not a MainActivity which is your custom subclass. You can easily fix this with a cast. For example, in your fragment, you can do this:

OnDataPass main = (OnDataPass) getActivity();
main.onDataPass(message);

Since such a cast is required, the interface seems to get in the way in my opinion. You can just as easily cast directly to MainActivity:

MainActivity main = (MainActivity) getActivity();
main.onDataPass(message);