[Android]RecyclerViewを使ってListViewを作る

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerview1"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:id="@+id/text01"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="18sp"
        android:padding="10dp"/>

</LinearLayout>

public class MainActivity extends AppCompatActivity {
    //リストに表示するデータ
    private final static String[] listDatas = {
            "ONE","TWO","THREE","FOUR",
            "FIVE","SIX","SEVEN","EIGHT",
            "NINE","TEN","ELEVEN","TWELVE",
            "THIRTEEN","FOURTEEN","FIFTEEN","SIXTEEN",
            "SEVENTEEN","EIGHTEEN","NINETEEN","TWENTY"    };

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

        final RecyclerView recyclerView = findViewById(R.id.recyclerview1);
        //LayoutManagerを設定
        //縦方向のリストはLinearLayoutManagerを使う
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        layoutManager.setOrientation(LinearLayoutManager.VERTICAL); //縦方向に設定
        recyclerView.setLayoutManager(layoutManager);
        //ItemDecorationを設定
        //DividerItemDecorationはリストに罫線を引くためのItemDecoration
        DividerItemDecoration itemDecoration = new DividerItemDecoration(this, layoutManager.getOrientation());
        recyclerView.addItemDecoration(itemDecoration);
        //アダプタのセット
        SampleRecyclerAdapter adapter = new SampleRecyclerAdapter(listDatas);
        recyclerView.setAdapter(adapter);
    }

    /* -------------------------------------------------------
    * RecyclerViewのアダプタ
    * --------------------------------------------------------*/
    class SampleRecyclerAdapter extends RecyclerView.Adapter<SampleRecyclerAdapter.SampleViewHolder> {
        //メンバ変数
        String[] itemDatas; //リストのデータを保持する変数

        //コンストラクタ
        SampleRecyclerAdapter(String[] itemDatas) {
            //データをコンストラクタで受け取りメンバ変数に格納
            this.itemDatas = itemDatas;
        }

        @NonNull
        @Override
        public SampleViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
            //onCreateViewHolder()ではリスト一行分のレイアウトViewを生成する
            //作成したViewはViewHolderに格納してViewHolderをreturnで返す

            //レイアウトXMLからViewを生成
            View view = LayoutInflater.from(viewGroup.getContext())
                    .inflate(R.layout.listitem_recyclerview1, viewGroup, false);
            //ViewHolderを生成してreturn
            SampleViewHolder holder = new SampleViewHolder(view);
            return holder;
        }

        @Override
        public void onBindViewHolder(@NonNull SampleViewHolder sampleViewHolder, int position) {
            //onBindViewHolder()ではデータとレイアウトの紐づけを行なう
            sampleViewHolder.text01.setText(itemDatas[position]);
        }

        @Override
        public int getItemCount() {
            //データ個数を返す
            return itemDatas.length;
        }

        /* ViewHolder（インナークラス） */
        class SampleViewHolder extends RecyclerView.ViewHolder {
            TextView text01;

            SampleViewHolder(@NonNull View itemView) {
                super(itemView);
                text01 = itemView.findViewById(R.id.text01);
            }
        }
    }
}