Shared element activity transition on android 5

Question

I wanted to setup a shared element transition when going from one Activity to another.

The first Activity has a RecyclerView with items. When an item is clicked that it

Answer 1

The reason for this is actually quite simple: When you Navigate back to the parent Activity or Fragment, the View is not there yet (could be for many reasons).
So, what you want to do is to postpone the Enter Transition until the View is available.

My work around is to call the following function in onCreate() in my Fragment (but works in Activity too):

private void checkBeforeTransition() {
    // Postpone the transition until the window's decor view has
    // finished its layout.
    getActivity().supportPostponeEnterTransition();

    final View decor = getActivity().getWindow().getDecorView();
    decor.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
        @Override
        public boolean onPreDraw() {
            decor.getViewTreeObserver().removeOnPreDrawListener(this);
            getActivity().supportStartPostponedEnterTransition();
            return true;
        }
    });
}