ボタンが押下されたら、TextViewに配列が順番に表示される。

Question

Java初心者です。
タイトルと重複しますが、ボタンが押下されると配列の文字列が順番に1つずつ表示させるにはどうすればよいですか？テキスト表示に、時間差で自由に設定できるスリープ機能も追加したいです。

   public void SetButtonOnClick(View v) {
        TextView message;
        message = (TextView) this.findViewById(R.id.Text1);

        String[] word = { "Pretty, Cool, Weird" };
        StringBuilder builder = new StringBuilder();

        String[] fruits = word.split(",");
        for (String s: fruits)
        {
            builder.append(s);
            builder.append(" ");
            message.setText(builder.toString().trim());
        }

Answer 1

MainActivity.java

import androidx.appcompat.app.AppCompatActivity;

import android.os.*;
import android.text.*;
import android.widget.*;

class ContinuousSetter implements Runnable {
  interface Callback {
    void begin(ContinuousSetter setter);
    void end(ContinuousSetter setter);
  }

  private Handler handler;
  private TextView view;
  private int length = -1;
  private long delay = 200; //[ms]
  private Object[] lock = new Object[0];

  private String text;
  private Callback callback;

  ContinuousSetter(Handler handler, TextView view) {
    this.handler = handler;
    this.view = view;
  }

  boolean isRunning() {
    return (length >= 0);
  }

  void start(String text, Callback callback) {
    if(text == null) throw new NullPointerException();
    synchronized(lock) {
      if(length >= 0) return;
      length = 0;
    }
    this.text = text;
    this.callback = callback;

    view.setText("");
    if(this.callback != null) callback.begin(this);
    handler.postDelayed(this, delay);
  }

  @Override
  public void run() {
    synchronized(lock) {
      if(++length <= text.length()) {
        view.setText(text.substring(0, length));
        if(length < text.length()) {
          handler.postDelayed(this, delay);
          return;
        }
      }
      length = -1;
      if(this.callback != null) callback.end(this);
      callback = null;
      text = null;
    }
  }
}

public class MainActivity extends AppCompatActivity {

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

    EditText editText = findViewById(R.id.editText);

    TextView textView = findViewById(R.id.textView);
    ContinuousSetter setter = new ContinuousSetter(new Handler(getMainLooper()), textView);

    Button startButton = findViewById(R.id.startButton);
    startButton.setOnClickListener(v -> {
      setter.start(editText.getText().toString(),
              new ContinuousSetter.Callback() {
                @Override
                public void begin(ContinuousSetter setter) {
                  startButton.setEnabled(false);
                }
                @Override
                public void end(ContinuousSetter setter) {
                  startButton.setEnabled(true);
                }
              });
    });

    editText.addTextChangedListener(new TextWatcher() {
      @Override
      public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
      @Override
      public void onTextChanged(CharSequence s, int start, int before, int count) {}
      @Override
      public void afterTextChanged(Editable s) {
        if(!setter.isRunning()) startButton.setEnabled(s.length() > 0);
      }
    });
  }
}

レイアウト: activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

  <EditText
      android:id="@+id/editText"
      android:layout_width="0dp"
      android:layout_height="wrap_content"
      android:hint="message"
      android:text="Pretty, Cool, Weird"
      android:textSize="20dp"
      app:layout_constraintBottom_toTopOf="@id/startButton"
      app:layout_constraintLeft_toLeftOf="parent"
      app:layout_constraintRight_toRightOf="parent"
      app:layout_constraintTop_toTopOf="parent" />

  <Button
      android:id="@+id/startButton"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="start"
      app:layout_constraintBottom_toTopOf="@id/textView"
      app:layout_constraintLeft_toLeftOf="parent"
      app:layout_constraintRight_toRightOf="parent"
      app:layout_constraintTop_toBottomOf="@id/editText" />

  <TextView
      android:id="@+id/textView"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Hello World!"
      android:textSize="20dp"
      app:layout_constraintBottom_toBottomOf="parent"
      app:layout_constraintLeft_toLeftOf="parent"
      app:layout_constraintRight_toRightOf="parent"
      app:layout_constraintTop_toBottomOf="@id/startButton" />
</androidx.constraintlayout.widget.ConstraintLayout>