Android recyclerview issue with animations

Question

I'm trying to make cardviews in recyclerview expand. I got the expanding part working, but when adding transition to it, some visual bugs start to occur. The transitions works fine, when there are no off-screen items, but when I add more than (in my case) 4 items to the recyclerview, it starts to occur.

GIF with 4 items

GIF with more than 4 items

The cardview expanding works fine with more than 4 items when I disable the transition animation. I think the problem is related to positions changing, but I can't find any solution to the problem.

The guide I used to implement the cardview expanding can be found here: https://stackoverflow.com/a/38623873/6673949

And my complete recyclerview adapter

public class BasketRecyclerAdapter extends RecyclerView.Adapter<BasketRecyclerAdapter.CustomViewHolder> {
private String letter;
private Context mContext;
private ColorGenerator generator = ColorGenerator.MATERIAL;
private List<Basket> baskets;
private int mExpandedPosition = -1;
private RecyclerView r1;

public BasketRecyclerAdapter(Context context, List<Basket> baskets, RecyclerView r1) {
    this.mContext = context;
    this.baskets = baskets;
    this.r1 = r1;

}

@Override
public CustomViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
    View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.basket_menu_item, null);
    CustomViewHolder viewHolder = new CustomViewHolder(view);
    return viewHolder;
}

@Override
public void onBindViewHolder(final BasketRecyclerAdapter.CustomViewHolder holder, final int position) {

    String basketName = baskets.get(position).getBasketName();

    holder.basketName.setText(basketName);

    letter = "" + basketName.charAt(0);

    TextDrawable drawable = TextDrawable.builder()
            .buildRound(letter, generator.getColor(basketName));


    holder.imageLetter.setImageDrawable(drawable);

    final boolean isExpanded = position == mExpandedPosition;
    holder.expandedLayout.setVisibility(isExpanded?View.VISIBLE:View.GONE);
    holder.itemView.setActivated(isExpanded);
    holder.itemView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            mExpandedPosition = isExpanded ? -1:position;
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
                TransitionManager.beginDelayedTransition(r1);
            }
            notifyDataSetChanged();
        }
    });


}

What can be done to solve the problem? Thanks.

Edit: I tried to get it to work by using just ListView instead of RecyclerView, but ListView adapter doesn't expand with same code - will try to figure out why.

Edit2: Got it working by using another library called "ExpandableLayout" but still can't seem to figure out why is it not working without additional libraries.

Answer 1

I had similar issue. Add in adapter:

@Override
public long getItemId(int position) {
    return position;
}

And myAdapter.setHasStableIds(true);