RecyclerView Q&A : <p>I'm creating a Q&amp;A where each question is a card.  The answer starts showing the first line, but when its clicked it should expanded to show the full answer.</p>

<p>When an answer is expanded/collapsed the rest of the RecyclerView should animate to make room for the expansion or collapse to avoid showing a blank space.</p>

<p>I watched the talk on <a href="https://www.youtube.com/watch?v=imsr8NrIAMs">RecyclerView animations</a>, and believe I want a custom ItemAnimator, where I override animateChange.  At that point I should create an ObjectAnimator to animate the height of the View's LayoutParams.  Unfortunately I'm having a hard time tying it all together. I also return true when overriding canReuseUpdatedViewHolder, so we reuse the same viewholder.</p>

<pre><code>@Override
public boolean canReuseUpdatedViewHolder(RecyclerView.ViewHolder viewHolder) {
    return true;
}


@Override
public boolean animateChange(@NonNull RecyclerView.ViewHolder oldHolder,
                             @NonNull final RecyclerView.ViewHolder newHolder,
                             @NonNull ItemHolderInfo preInfo,
                             @NonNull ItemHolderInfo postInfo) {
    Log.d("test", "Run custom animation.");

    final ColorsAdapter.ColorViewHolder holder = (ColorsAdapter.ColorViewHolder) newHolder;

    FrameLayout.LayoutParams params = (FrameLayout.LayoutParams) holder.tvColor.getLayoutParams();
    ObjectAnimator halfSize = ObjectAnimator.ofInt(holder.tvColor.getLayoutParams(), "height", params.height, 0);
    halfSize.start();
    return super.animateChange(oldHolder, newHolder, preInfo, postInfo);
}
</code></pre>

<p>Right now I'm just trying to get something to animate, but nothing happens...  Any ideas?</p>
