android - Item click listeners for RecyclerView

Question

I have been trying to work on RecycleView item click listener. I have come up with following solution. I would like to know if this solution is correct or just a "hack".

public class CityListAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    private Context context;
    private int lastPosition = -1;
    private int focusedItem = 0;
    private static Interfaces.OnCityItemClickListener cityItemClickListner;

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

        private TextView cityNameTextView, tempTextView, humidityTextView, timeTextView;
        private ImageView weatherStatusImageView;
        private CardView cardView;

        public ViewHolder(View itemView) {
            super(itemView);
            cityNameTextView = (TextView) itemView.findViewById(R.id.city_name_tv);
            tempTextView = (TextView) itemView.findViewById(R.id.temp_tv);
            humidityTextView = (TextView) itemView.findViewById(R.id.humidity_tv);
            timeTextView = (TextView) itemView.findViewById(R.id.time_tv);
            cardView = (CardView) itemView.findViewById(R.id.card_view);
            itemView.setOnClickListener(this);
        }


        @Override
        public void onClick(View v) {
            cityItemClickListner.onCityItemClick(getAdapterPosition(), v);
        }
    }

    public CityListAdapter(Context context){
        this.context = context;
    }

    public void setOnCityItemClickListener(Interfaces.OnCityItemClickListener clickListener){
        cityItemClickListner = clickListener;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        View view = LayoutInflater.from(context).inflate(R.layout.row_city, parent, false);
        ViewHolder holder = new ViewHolder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        ViewHolder myViewHolder = (ViewHolder) holder;
        myViewHolder.itemView.setSelected(focusedItem == position);
    }

    @Override
    public int getItemCount() {
        return 15;
    }
}

Then in my Activity

adapter.setOnCityItemClickListener(new Interfaces.OnCityItemClickListener() {
            @Override
            public void onCityItemClick(int position, View view) {
                Toast.makeText(BaseActivity.this, "Clicked position " + position, Toast.LENGTH_SHORT).show();
            }
        });

Answer 1

This blog post by Hugo shows an alternative way without listeners: http://www.littlerobots.nl/blog/Handle-Android-RecyclerView-Clicks/

It comes down to adding these lines:

ItemClickSupport.addTo(mRecyclerView).setOnItemClickListener(new ItemClickSupport.OnItemClickListener() {
    @Override
    public void onItemClicked(RecyclerView recyclerView, int position, View v) {
        // do it
    }
});

When using this class:

public class ItemClickSupport {
   private final RecyclerView mRecyclerView;
   private OnItemClickListener mOnItemClickListener;
    private OnItemLongClickListener mOnItemLongClickListener;
    private View.OnClickListener mOnClickListener = new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (mOnItemClickListener != null) {
                RecyclerView.ViewHolder holder = mRecyclerView.getChildViewHolder(v);
                mOnItemClickListener.onItemClicked(mRecyclerView, holder.getAdapterPosition(), v);
            }
        }
    };
    private View.OnLongClickListener mOnLongClickListener = new View.OnLongClickListener() {
        @Override
        public boolean onLongClick(View v) {
            if (mOnItemLongClickListener != null) {
                RecyclerView.ViewHolder holder = mRecyclerView.getChildViewHolder(v);
                return mOnItemLongClickListener.onItemLongClicked(mRecyclerView, holder.getAdapterPosition(), v);
            }
            return false;
        }
    };
    private RecyclerView.OnChildAttachStateChangeListener mAttachListener
            = new RecyclerView.OnChildAttachStateChangeListener() {
        @Override
        public void onChildViewAttachedToWindow(View view) {
            if (mOnItemClickListener != null) {
                view.setOnClickListener(mOnClickListener);
            }
            if (mOnItemLongClickListener != null) {
                view.setOnLongClickListener(mOnLongClickListener);
            }
        }

        @Override
        public void onChildViewDetachedFromWindow(View view) {

        }
    };

    private ItemClickSupport(RecyclerView recyclerView) {
        mRecyclerView = recyclerView;
        mRecyclerView.setTag(R.id.item_click_support, this);
        mRecyclerView.addOnChildAttachStateChangeListener(mAttachListener);
    }

    public static ItemClickSupport addTo(RecyclerView view) {
        ItemClickSupport support = (ItemClickSupport) view.getTag(R.id.item_click_support);
        if (support == null) {
            support = new ItemClickSupport(view);
        }
        return support;
    }

    public static ItemClickSupport removeFrom(RecyclerView view) {
        ItemClickSupport support = (ItemClickSupport) view.getTag(R.id.item_click_support);
        if (support != null) {
            support.detach(view);
        }
        return support;
    }

    public ItemClickSupport setOnItemClickListener(OnItemClickListener listener) {
        mOnItemClickListener = listener;
        return this;
    }

    public ItemClickSupport setOnItemLongClickListener(OnItemLongClickListener listener) {
        mOnItemLongClickListener = listener;
        return this;
    }

    private void detach(RecyclerView view) {
        view.removeOnChildAttachStateChangeListener(mAttachListener);
        view.setTag(R.id.item_click_support, null);
    }

    public interface OnItemClickListener {

        void onItemClicked(RecyclerView recyclerView, int position, View v);
    }

    public interface OnItemLongClickListener {

        boolean onItemLongClicked(RecyclerView recyclerView, int position, View v);
    }
}

And this value in ids.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <item name="item_click_support" type="id" />
</resources>