Android Studio播放音频问题

import android.media.MediaPlayer;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    private MediaPlayer mediaPlayer;

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

        // 初始化MediaPlayer
        mediaPlayer = MediaPlayer.create(this, R.raw.my_audio);
    }

    @Override
    protected void onStart() {
        super.onStart();
        // 开始播放音频
        mediaPlayer.start();
    }

    @Override
    protected void onStop() {
        super.onStop();
        // 停止播放音频并释放资源
        mediaPlayer.stop();
        mediaPlayer.release();
        mediaPlayer = null;
    }
}