java - Android 中 MediaPlayer 数组导致空指针

Question

谁能明白为什么我会用这段代码得到 NullPointerException 吗？该代码基本上是创建一个 MediaPlayer 数组，以便我可以循环遍历它并立即停止/启动所有媒体播放器。它们还链接到搜索栏来控制音量。

private MediaPlayer[] media;


/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


    //media players

    media[0] = MediaPlayer.create(this, R.raw.drums);



    media[1] = MediaPlayer.create(this, R.raw.bass);


    media[2] = MediaPlayer.create(this, R.raw.synth);


    media[3] = MediaPlayer.create(this, R.raw.snare);


    media[4]  = MediaPlayer.create(this, R.raw.wobble);


    for(int i=0;i<media.length;i++){
         media[i].start();
         media[i].setLooping(true);
         media[i].setVolume(0,0);
    }


   //drums seekbar

    final SeekBar volControl = (SeekBar)findViewById(R.id.volbar);
    volControl.setMax(maxVolume);       
    volControl.setProgress(0);
    volControl.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() { 



        @Override
        public void onStopTrackingTouch(SeekBar arg0) {
            // TODO Auto-generated method stub

        }


        @Override
        public void onStartTrackingTouch(SeekBar arg0) {
            // TODO Auto-generated method stub
        }

        @Override
        public void onProgressChanged(SeekBar arg0, int arg1, boolean arg2) {
            // TODO Auto-generated method stub

            media[0].setVolume(arg1, arg1);

        }                       

    });       

Answer 1

使用类似

 media=new MediaPlayer[5]; 

然后

media[0] = MediaPlayer.create(this, R.raw.drums);
media[1] = MediaPlayer.create(this, R.raw.bass);
media[2] = MediaPlayer.create(this, R.raw.synth);
media[3] = MediaPlayer.create(this, R.raw.snare);