How to highlight selected item in RecyclerView

Question

I have used RecyclerView for showing thumbnails in my Image Editing app.Each item of its comprises of a ImageView(thumbnail) and a textView.In my application I want to

Answer 1

update your enum to class first for flag

public class Type {
    public int type; // 0-Original,1-Grayscale,2-Sepia.... same as enum
    public int selected;
}

now in adapter

@Override
public void onBindViewHolder(FiltersAdapter.ViewHolder holder, int position) {
    int typeOfItem = mDataSet.get(position).type
    switch (mDataSet.get(position)) {
        case 0:
            holder.image.setImageResource(R.drawable.no_filter);
            break;
        case 1:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new GrayscaleTransformation())
                    .into(holder.image);
            break;
        case 2:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new SepiaFilterTransformation(mContext))
                    .into(holder.image);
            break;
        case 3:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new ContrastFilterTransformation(mContext, 2.0f))
                    .into(holder.image);
            break;
        case 4:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new InvertFilterTransformation(mContext))
                    .into(holder.image);
            break;
        case 5:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new PixelationFilterTransformation(mContext, 20))
                    .into(holder.image);
            break;
        case 6:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new SketchFilterTransformation(mContext))
                    .into(holder.image);
            break;
        case 7:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new SwirlFilterTransformation(mContext, 0.5f, 1.0f, new PointF(0.5f, 0.5f)))
                    .into(holder.image);
            break;
        case 8:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new BrightnessFilterTransformation(mContext, 0.5f))
                    .into(holder.image);
            break;
        case 9:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new VignetteFilterTransformation(mContext, new PointF(0.5f, 0.5f),
                            new float[]{0.0f, 0.0f, 0.0f}, 0f, 0.75f))
                    .into(holder.image);
            break;
        default:
            holder.image.setImageResource(R.drawable.no_filter);
            break;
    }
    holder.title.setText(mDataSet.get(position).name());
    if(mDataSet.get(position).selected == 0){
        holder.title.setTypeface(null, Typeface.BOLD);
    } else {
        holder.title.setTypeface(null,Typeface.NORMAL);
    }
}

not on every click or select update your list then call notifydatasetChanged() of adapter

Answer 2

If you don't want to use notifyDataSetChanged
Implemented by kotlin

 override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    adapterOrders = OrdersSendAdapter(this, listOrders)
    recyclerOrders = view.findViewById<RecyclerView>(R.id.recycler_orders)
    recyclerOrders.layoutManager = LinearLayoutManager(activity)
    recyclerOrders.setHasFixedSize(true)
    recyclerOrders.addItemDecoration(DividerItemDecoration(activity, DividerItemDecoration.VERTICAL))
    recyclerOrders.adapter = adapterOrders
  }

/* This method will be call when item of adapter has an event */
fun getListDetail(position: Int, idOrders: String) {
    for (index in 0 until recyclerOrders.childCount) {
         recyclerOrders[index].setBackgroundColor(Color.parseColor("#ffffff"))
    }
    recyclerOrders[position].setBackgroundColor(ContextCompat.getColor(context!!, R.color.color_select))
}