Adapter implementation

Create a class called RecyclerViewAdapter in the adapter package created earlier. Inside the class, let's create an inner class called ViewHolder for mapping the components created in the each_item.xml layout. ViewHolder will extend RecyclerView.ViewHolder and, inside its constructor, it will map the XML component. The code looks as follows:

public class RecyclerViewAdapter {

    static class ViewHolder extends RecyclerView.ViewHolder{

        private TextView mTextView;

        public ViewHolder(View view) {
            super(view);
            mTextView = (TextView) view.findViewById(R.id.note);
        }
    }
}

Now, create an interface for the ItemClick events, which returns the position: 

 public interface ItemSelectedListener {
     void onItemSelected(int position);
 }

Inside the ViewHolder class, add the bind method for binding the click event and returning the position:

void bind(final String title, final int position, final ItemSelectedListener listener) {

    mTextView.setText(title);
    itemView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (listener != null) {
                listener.onItemSelected(position);
            }
        }
    });
}

In the RecyclerViewAdapter class scope, declare the following instances:

private ItemSelectedListener mItemSelectedListener;
private List<Note> mListNote = new ArrayList<>();

Set the listner for ItemSelectedListner as follows: 

public void setListener(ItemSelectedListener itemSelectedListener) {
    mItemSelectedListener = itemSelectedListener;
}

Now, we need to extend RecyclerViewAdapter to WearableRecyclerView.Adapter with its view holder, as follows: 

public class RecyclerViewAdapter extends WearableRecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> {

}

We then need to implement the callbacks for the adapter: 

• onCreateViewHolder(..);
• onBindViewHolder(..);
• getItemCount(..);

Inside onCreateViewHolder, we should attach or inflate the each_item.xml layout: 

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

 View view = LayoutInflater.from(parent.getContext())
 .inflate(R.layout.view_holder, parent, false);

 return new ViewHolder(view);
 }

Inside onBindViewHolder, we will handle the click event by binding the data and position: 

@Override
public void onBindViewHolder(ViewHolder holder, int position) {
    holder.bind(mListNote.get(position).getNotes(), position, 
    mItemSelectedListener);
}

Inside the getItemCount() method, we will return the count of the list item being passed to the adapter: 

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

The complete WearableRecyclerView adapter looks as follows: 

package com.ashok.packt.wear_note_1.adapter;

import android.support.v7.widget.RecyclerView;
import android.support.wearable.view.WearableRecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import com.ashok.packt.wear_note_1.R;
import com.ashok.packt.wear_note_1.model.Note;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by ashok.kumar on 15/02/17.
 */

public class RecyclerViewAdapter
        extends WearableRecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> {

    private ItemSelectedListener mItemSelectedListener;
    private List<Note> mListNote = new ArrayList<>();

    static class ViewHolder extends RecyclerView.ViewHolder {
        private TextView mTextView;

        ViewHolder(View view) {
            super(view);
            mTextView = (TextView) view.findViewById(R.id.note);
        }

        void bind(final String title, final int position, final 
        ItemSelectedListener listener) {
            mTextView.setText(title);
            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if (listener != null) {
                        listener.onItemSelected(position);
                    }
                }
            });
        }
    }

    public void setListener(ItemSelectedListener itemSelectedListener) 
    {
        mItemSelectedListener = itemSelectedListener;
    }

    public void setListNote(List<Note> listNote) {
        mListNote.clear();
        mListNote.addAll(listNote);
        notifyDataSetChanged();
    }

    @Override
    public RecyclerViewAdapter.ViewHolder onCreateViewHolder(ViewGroup 
    parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.each_item, parent, false);

        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.bind(mListNote.get(position).getNotes(), position, 
        mItemSelectedListener);
    }

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

    public interface ItemSelectedListener {
        void onItemSelected(int position);
    }
}

Now, let's put all these pieces of codes for action in MainActivity.java.