Select items in RecyclerView

Question

Similar question have been asked, but i can\'t get any of them work.

What i want is to select item in RecyclerView, change the background of that item view, and stor

Answer 1

First of all, you asked where to put the onClickListener - you should put it in the onBindViewHolder. You can also attach a onClickListener in the ViewHolder class of your item like so:

public class ViewHolder extends RecyclerView.ViewHolder {
        public ViewHolder(View itemView) {
            super(itemView);
            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                }
            });
        }
    }

As to implementing a single selection behaviour, the answers given here work but calling onNotifyDatasetChanged is bad for performance if you have a lot of items as it rebinds all views from scratch each time.

The link given by Rafiduzzaman Sonnet is a good tutorial to understand a lot of things about setting up RecyclerView, but I think it makes single selection behaviour complicated. I am going to answer comprehensively giving everything one might need to make it work. Here's how I implemented the single selection behaviour:

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
    final YourItemViewHolder itemViewHolder = (YourItemViewHolder) holder;
    //This will remember which one was selected
    itemViewHolder.getItemSelectionIndicator()
            .setSelected(position == mSelectedPosition);
        itemViewHolder.getItemWrapperView()
            .setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Log.d(mLogTag, "Tapped on " + position);
                    //This is the previous selection
                    notifyItemChanged(mSelectedPosition);
                    itemViewHolder.getItemSelectionIndicator().setSelected(true);
                    mSelectedPosition = position;
                    //This is the new selection
                    notifyItemChanged(position);
                }
            });

getItemSelectionIndicator() and getItemWrapperView() are methods inside the item's ViewHolder that return specific views from the item layout. A ItemWrapperView could be the top most Linear/RelativeLayout that wraps the entire item. Setting a click listener on it will ensure clicks work if user taps anywhere in the item's view.

ItemSelectionIndicator can be a Linear or RelativeLayout that has been set a state list drawable background. This means when it is set as selected, it shows a shape drawable automatically to indicate selection. When it is set as unselected, the drawable will be removed automatically. This is what the indicator view looks like:

This is selection_indicator_state_list.xml in res/drawable:

And this is item_selection_shape.xml in res/drawable:

    //22 is value of transparency, BDBDBD is the color