How to implement mini equalizer on selected item of RecyclerView?

Question

I have a recyclerview whose listitem is designed as follows

• LinearLayout(Horizontal)
  • ImageView
  • TextView
  • ImageButton(PlayButton)
  • EqualizerView(Invisible)

Now when I click on PlayButton, it should hide and equalizer show be displayed and if I scroll the list, equalizer should stay on selected item only.

However, I am facing problem that EqualizerView is being displayed at interval of 10 items. That is if I click on 3rd item then equalizer will be displayed on 3rd,13th and so on..

I am using this https://github.com/claucookie/mini-equalizer-library-android library for implementing mini equalizer.

public class StationViewAdapter extends RecyclerView.Adapter<StationViewAdapter.StationViewHolder> {

    List<Station> statons;
    final private ListItemClickListener mOnClickListener;

    public  StationViewAdapter (List<Station> s, ListItemClickListener l)
    {
        statons = s;
        mOnClickListener = l;
    }

    @NonNull
    @Override
    public StationViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item,parent,false);
        return new StationViewHolder(v);
    }

    @Override
    public void onBindViewHolder(@NonNull final StationViewHolder holder, int position) {

        Station station = statons.get(position);
        if(!station.getArtwork().isEmpty() && station.getArtwork() != null)
        {
            try{
                Picasso.get().load(Uri.parse(station.getArtwork()))
                       // .placeholder(R.mipmap.ic_launcher)
                        .into(holder.stationArtwork);
            } catch (Exception e) {
                e.printStackTrace();
                holder.stationArtwork.setImageResource(R.mipmap.ic_launcher);
            }
        }
        else
            holder.stationArtwork.setImageResource(R.mipmap.ic_launcher);
        holder.stationName.setText(station.getName());

    }


    @Override
    public int getItemCount() {
        return statons.size();
    }

    public class StationViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

        ImageView stationArtwork;
        TextView stationName;
        ImageButton stationPlayButton;
        EqualizerView equalizerView;
        int selectedItem;
        public StationViewHolder(@NonNull View itemView) {
            super(itemView);
            stationArtwork = itemView.findViewById(R.id.favicon);
            stationName = itemView.findViewById(R.id.text);
            stationPlayButton = itemView.findViewById(R.id.play_button);
            equalizerView = itemView.findViewById(R.id.equalizer_view);
            itemView.setOnClickListener(this);
            stationPlayButton.setOnClickListener(this);
            selectedItem = getAdapterPosition();
        }

        @Override
        public void onClick(View v) {
            int clickPosition = getAdapterPosition();
            Log.d(TAG, "onClick: "+getAdapterPosition());
            Log.d(TAG, "onClick: "+getLayoutPosition());
            Log.d(TAG, "onClick: "+getItemId());
            if(v == itemView) {
                mOnClickListener.onListItemClick(clickPosition);
            }else if(v == stationPlayButton)
            {

                    mOnClickListener.onListItemPlay(clickPosition,stationPlayButton,equalizerView);

            }

        }
    }
    public interface ListItemClickListener {
        void onListItemClick(int clickedItemIndex);
        void onListItemPlay(int clickItemIndex,ImageButton i,EqualizerView eq);
    }
}

These are ClickListeners in Main Activity

@Override
public void onListItemClick(int clickedItemIndex) {

     if(mToast !=null)
     {
         mToast.cancel();
     }
     mToast = Toast.makeText(this,"Main Activity item clicked at position"+clickedItemIndex,Toast.LENGTH_SHORT);
     mToast.show();
}


@Override
public void onListItemPlay(int clickItemIndex,ImageButton i , EqualizerView eq) {

    i.setVisibility(View.GONE);
    eq.setVisibility(View.VISIBLE);
    eq.animateBars();

}

Answer 1

RecyclerView reuses ViewHolder instances. You need to invalidate ViewHolder state inside onBindViewHolder. In your case you should hide EqulizerView at least:

@Override
public void onBindViewHolder(@NonNull final StationViewHolder holder, int position) {
    equalizerView.setVisibility(View.INVISIBLE);
    ....
}

Also, you should save which songs are playing to initialize ViewHolder state later.

More info at: https://developer.android.com/guide/topics/ui/layout/recyclerview#structure