在媒体播放器中加载多个音乐媒体

Question

它不会加载 switch case 中声明的歌曲

    final ArrayList<Integer> playlist;


    playlist = new ArrayList<>();
    playlist.add(R.raw.honey);
    playlist.add(R.raw.anger);
    playlist.add(R.raw.contempt);
    playlist.add(R.raw.disgust);
    playlist.add(R.raw.fear);
    playlist.add(R.raw.happy);
    playlist.add(R.raw.sadness);
    playlist.add(R.raw.surprise);


    MediaPlayer mediaPlayer = null;
    Button play = findViewById(R.id.play);
    Button pause = findViewById(R.id.pause);
    Button jumpToMainActivity = findViewById(R.id.jumpToMainActivity);

    mediaPlayer = MediaPlayer.create(this,playlist.get(0));

    switch (final_detected_emotion){
        case "anger":
            mediaPlayer.reset();
            mediaPlayer.create(this,playlist.get(1));
            break;
        case "contempt":
            mediaPlayer.reset();
            mediaPlayer.create(this,playlist.get(2));
            break;
        case "disgust":
            mediaPlayer.reset();
            mediaPlayer.create(this,playlist.get(3));
            break;
        case "fear":
            mediaPlayer.reset();
            mediaPlayer.create(this,playlist.get(4));
            break;
        case "happy":
            mediaPlayer.reset();
            mediaPlayer.create(this,playlist.get(5));
            break;
        case "sadness":
            mediaPlayer.reset();
            mediaPlayer.create(this,playlist.get(6));
            break;
        case "surprise":
            mediaPlayer.reset();
            mediaPlayer.create(this,playlist.get(7));
            break;
    }
    final MediaPlayer finalMediaPlayer = mediaPlayer;

    play.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            finalMediaPlayer.start();
        }
    });

它只播放蜂蜜歌曲。传递的字符串 (final_detected_emotion) 发生了变化，但歌曲没有变化。

我会删除媒体播放器对象吗

我制作了可以根据检测到的情绪播放歌曲的应用程序

Answer 1

    switch (final_detected_emotion){
        case "anger":
           mediaPlayer = MediaPlayer.create(this,playlist.get(1));
            break;
        case "contempt":
           mediaPlayer = MediaPlayer.create(this,playlist.get(2));
            break;
        case "disgust":
            mediaPlayer = MediaPlayer.create(this,playlist.get(3));
            break;
        case "fear":
            mediaPlayer = MediaPlayer.create(this,playlist.get(4));
            break;
        case "happy":
            mediaPlayer = MediaPlayer.create(this,playlist.get(5));
            break;
        case "sadness":
           mediaPlayer = MediaPlayer.create(this,playlist.get(6));
            break;
        case "surprise":
            mediaPlayer = MediaPlayer.create(this,playlist.get(7));
            break;
        default :
            mediaPlayer = MediaPlayer.create(this,playlist.get(0));
    }