Detect animation finish in Android's RecyclerView

Question

The RecyclerView, unlike to ListView, doesn\'t have a simple way to set an empty view to it, so one has to manage it manually, making empty view vi

Answer 1

I have a little bit more generic case where I want to detect when the recycler view have finished animating completely when one or many items are removed or added at the same time.

I've tried Roman Petrenko's answer, but it does not work in this case. The problem is that onAnimationFinished is called for each entry in the recycler view. Most entries have not changed so onAnimationFinished is called more or less instantaneous. But for additions and removals the animation takes a little while so there it's called later.

This leads to at least two problems. Assume you have a method called doStuff() that you want to run when the animation is done.

1. If you simply call doStuff() in onAnimationFinished you will call it once for every item in the recycler view which might not be what you want to do.

2. If you just call doStuff() the first time onAnimationFinished is called you may be calling this long before the last animation has been completed.

If you could know how many items there are to be animated you could make sure you call doStuff() when the last animation finishes. But I have not found any way of knowing how many remaining animations there are queued up.

My solution to this problem is to let the recycler view first start animating by using new Handler().post(), then set up a listener with isRunning() that is called when the animation is ready. After that it repeats the process until all views have been animated.

void changeAdapterData() {
    // ...
    // Changes are made to the data held by the adapter
    recyclerView.getAdapter().notifyDataSetChanged();

    // The recycler view have not started animating yet, so post a message to the
    // message queue that will be run after the recycler view have started animating.
    new Handler().post(waitForAnimationsToFinishRunnable);
}

private Runnable waitForAnimationsToFinishRunnable = new Runnable() {
    @Override
    public void run() {
        waitForAnimationsToFinish();
    }
};

// When the data in the recycler view is changed all views are animated. If the
// recycler view is animating, this method sets up a listener that is called when the
// current animation finishes. The listener will call this method again once the
// animation is done.
private void waitForAnimationsToFinish() {
    if (recyclerView.isAnimating()) {
        // The recycler view is still animating, try again when the animation has finished.
        recyclerView.getItemAnimator().isRunning(animationFinishedListener);
        return;
    }

    // The recycler view have animated all it's views
    onRecyclerViewAnimationsFinished();
}

// Listener that is called whenever the recycler view have finished animating one view.
private RecyclerView.ItemAnimator.ItemAnimatorFinishedListener animationFinishedListener =
        new RecyclerView.ItemAnimator.ItemAnimatorFinishedListener() {
    @Override
    public void onAnimationsFinished() {
        // The current animation have finished and there is currently no animation running,
        // but there might still be more items that will be animated after this method returns.
        // Post a message to the message queue for checking if there are any more
        // animations running.
        new Handler().post(waitForAnimationsToFinishRunnable);
    }
};

// The recycler view is done animating, it's now time to doStuff().
private void onRecyclerViewAnimationsFinished() {
    doStuff();
}