从BackStack还原片段的事件

Question

I attach SessionFragment from SpeakerFragment with code:

FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
        fragmentManager.beginTransaction()
                .add(R.id.container, new SessionFragment(session))
                .addToBackStack("session")
                .commit();

In SessionFragment (in OnAttach()) I change ActionBar title to Session title.

When return back from SessionFragment, I want change ActionBar title to Speaker name. How can I do that?

OnStart(), OnResume(), onAttach() not calling.

Answer 1

You just added a fragment to the container without detaching or removing the previous one, try replace instead and set your ActionBar title in OnActivityCreated()

FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
fragmentManager.beginTransaction()
        .replace(R.id.container, new SessionFragment(session))
        .addToBackStack("session")
        .commit();

Another note, you shouldn't use a non-empty Constructor for Fragments, as the framework will only call the empty constructor when restoring a fragment eg after idling, background etc. Instead session's class should implement parcelable, and should be passed as fragment argument using fragment.setArguments() .