Android如何给按钮添加点击音效

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical">

  <Button
    android:id="@+id/btnPlay"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:layout_margin="5dp"
    android:text="Play Wav"
    tools:ignore="HardcodedText" />

</LinearLayout>

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

  private Button btnPlay;

  private SoundPool soundPool;//声明一个SoundPool
  private int soundID;//创建某个声音对应的音频ID

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_home);
    btnPlay = (Button) findViewById(R.id.btnPlay);
    btnPlay.setOnClickListener(this);
    initSound();
  }

  @SuppressLint("NewApi")
  private void initSound() {
    soundPool = new SoundPool.Builder().build();
    soundID = soundPool.load(this, R.raw.testsong, 1);
  }

  @Override
  public void onClick(View v) {
    switch (v.getId()) {
      case R.id.btnPlay:
        playSound();
        break;
    }
  }

  private void playSound() {
    soundPool.play(
        soundID,
        0.1f,   //左耳道音量【0~1】
        0.5f,   //右耳道音量【0~1】
        0,     //播放优先级【0表示最低优先级】
        1,     //循环模式【0表示循环一次，-1表示一直循环，其他表示数字+1表示当前数字对应的循环次数】
        1     //播放速度【1是正常，范围从0~2】
    );
  }
}

soundPool = new SoundPool(5, AudioManager.STREAM_MUSIC, 0);