MediaPlayer數組在Android中導致空指針

Question

誰能看到為什么我會通過此代碼得到NullPointerException？ 該代碼基本上是創建一個MediaPlayer數組，以便我可以遍歷它並立即停止/啟動所有mediaplayer。 它們還鏈接到搜索桿以控制音量。

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

使用像

 media=new MediaPlayer[5]; 

接着

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);

Answer 2

老兄，您沒有為Mediaplayer數組提供大小，反正嘗試以這種方式會有所幫助。

私有MediaPlayer [] mediaPlayer;

並在您活動的onCreate方法中將其大小設置為

mediaPlayer =新的MediaPlayer [10];