Debugging Bookends data set insertion

MainActivity.java

package com.kevintcoughlin.bookendsadaptertest;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.tumblr.bookends.Bookends;

import java.util.ArrayList;

public final class MainActivity extends AppCompatActivity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		final RecyclerView recyclerView = (RecyclerView) findViewById(R.id.list);
		final TextRecyclerAdapter adapter = new TextRecyclerAdapter();
		final Bookends<TextRecyclerAdapter> bookends = new Bookends<>(adapter);
		recyclerView.setLayoutManager(new LinearLayoutManager(this));
		recyclerView.setAdapter(bookends);

		final TextView headerView = new TextView(this);
		final TextView footerView = new TextView(this);

		headerView.setText("HEADER");
		footerView.setText("FOOTER");

		bookends.addHeader(headerView);
		bookends.addFooter(footerView);

		adapter.add("One");
		adapter.add("Two");
		adapter.add("Three");

		bookends.getWrappedAdapter().add("Four");
		bookends.getWrappedAdapter().add("Five");
		bookends.getWrappedAdapter().add("Six");

		adapter.add("Seven");
		adapter.add("Eight");
		adapter.add("Nine");
	}

	private final class TextRecyclerAdapter extends RecyclerView.Adapter<TextRecyclerAdapter.ViewHolder> {
		private final ArrayList<String> mItems = new ArrayList<>();

		@Override
		public TextRecyclerAdapter.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
			final View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.my_text_view, viewGroup, false);
			return new ViewHolder(v);
		}

		@Override
		public void onBindViewHolder(ViewHolder viewHolder, int i) {
			viewHolder.mTextView.setText(mItems.get(i));
		}

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

		public void add(final String s) {
			mItems.add(s);
		}

		public final class ViewHolder extends RecyclerView.ViewHolder {

			public final TextView mTextView;

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

}