Mediaplayer NullPointerException问题

Question

我在我的应用程序中使用mediaplayer。我的应用程序正常工作，但我看到谷歌播放开发者控制台上的错误报告（对于某些用户）问题在哪里，谢谢

public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    soundname= new String[] {"Sound1","Sound2","Sound3","Sound4","Sound5","Sound6"}; 
    soundfile= new int[] {R.raw.sound1,R.raw.sound2,R.raw.sound3,R.raw.sound4,R.raw.sound5,R.raw.sound6}; 

    this.setContentView(R.layout.single_list_item_view); 

    TextView txtProduct = (TextView) findViewById(R.id.product_label); 
    Intent intent = getIntent(); 
    int position = intent.getExtras().getInt("position"); 

    txtProduct.setText(soundname[position]); 
    mediaPlayer = MediaPlayer.create(this, soundfile[position]); 

    Button btnplay= (Button) findViewById(R.id.btnoynat); 
    btnplay.setOnClickListener(new View.OnClickListener(){ 

     public void onClick(View arg0) { 
       mediaPlayer.start();   
     } 
     }); 

错误日志; （mediaPlayer.start（）; - > SingleListItem.java:60）

java.lang.NullPointerException 
at com.zilsesleri.SingleListItem$1.onClick(SingleListItem.java:60) 
at android.view.View.performClick(View.java:2538) 
at android.view.View$PerformClick.run(View.java:9152) 
at android.os.Handler.handleCallback(Handler.java:587) 
at android.os.Handler.dispatchMessage(Handler.java:92) 
at android.os.Looper.loop(Looper.java:130) 
at android.app.ActivityThread.main(ActivityThread.java:3693) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:507) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:907) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:665) 
at dalvik.system.NativeStart.main(Native Method) 

Answer 1

错误是在这一行mediaPlayer.start();，你的MediaPlayer对象是空在这里，有一个空检查，并弄清楚在什么情况下，应该为空。