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

I had this same issue, for me it was being caused by the recyclerview executing updates after/during the first exit transition. I think the shared element view was then sometimes getting recycled, meaning it would no longer be available for the transition animation, hence the crash (normally on the return transition but sometimes on the exit transition). I solved it by blocking updates if the activity is paused (used an isRunning flag) - note it was pausing but not stopping as it was still visible in the background. Additionally I blocked the update process if the transition was running. I found it enough to listen to this callback:

Transition sharedElementExitTransition = getWindow().getSharedElementExitTransition();
        if (sharedElementExitTransition != null) {
            sharedElementExitTransition.addListener(.....);
        }

As a final measure, although i'm not sure if this made a difference, I also did recyclerView.setLayoutFrozen(true) / recyclerView.setLayoutFrozen(false) in the onTransitionStart / onTransitionEnd.