在没有新捆绑包的情况下启动意图

Question

我有一个列表单击方法，它启动一个新活动并为其提供一个捆绑包

protected void onListItemClick(ListView l , View v, int position, long id){
  super.onListItemClick(l, v, position, id);


  Intent lis = new Intent(this, MusicService.class);
  stopService(lis);  

  Object o = this.getListAdapter().getItem(position);
  String songpen = o.toString();
  String artwork = albumartwork.get(songtitle.indexOf(songpen));
  String artistpen = artistname.get(songtitle.indexOf(songpen)); 
  String albumpen = albumname.get(songtitle.indexOf(songpen));
  String pathpen = path.get(songtitle.indexOf(songpen));

  int songpos = songtitle.indexOf(o);

    Intent i  = new Intent(IplayerActivity.this, SongPlaying.class);
    i.putExtra("songnamekeyword", songpen);
    i.putExtra("artistkeyword", artistpen);
    i.putExtra("albumkeyword", albumpen);
    i.putExtra("pathkeyword", pathpen);
    i.putExtra("artworkkeyword", artwork);

    i.putExtra("position", songpos);

    i.putExtra("nextsong", songtitle);
    i.putExtra("nextartist", artistname);
    i.putExtra("nextalbum", albumname);
    i.putExtra("nextpath", path);
    i.putExtra("nextartwork", albumartwork);

    startActivity(i);

}

我想创建一个正在播放的捆绑包，它使用与已有的信息完全相同的信息启动歌曲播放类...基本上我只想继续上课，不做任何改变。但是当我这样做时

             Intent k = new Intent(this, SongPlaying.class);        
            startActivity(k);

我收到错误。我只想使用以前已有的信息重新加载 SongPlaying 类。

11-28 15:46:50.943: ERROR/AndroidRuntime(817): FATAL EXCEPTION: main
11-28 15:46:50.943: ERROR/AndroidRuntime(817): java.lang.RuntimeException: Unable to create service unjustentertainment.com.MusicService: java.lang.NullPointerException
11-28 15:46:50.943: ERROR/AndroidRuntime(817):     at android.app.ActivityThread.handleCreateService(ActivityThread.java:2969)
11-28 15:46:50.943: ERROR/AndroidRuntime(817):     at android.app.ActivityThread.access$3300(ActivityThread.java:125)
11-28 15:46:50.943: ERROR/AndroidRuntime(817):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2087)
11-28 15:46:50.943: ERROR/AndroidRuntime(817):     at android.os.Handler.dispatchMessage(Handler.java:99)
11-28 15:46:50.943: ERROR/AndroidRuntime(817):     at android.os.Looper.loop(Looper.java:123)
11-28 15:46:50.943: ERROR/AndroidRuntime(817):     at android.app.ActivityThread.main(ActivityThread.java:4627)
11-28 15:46:50.943: ERROR/AndroidRuntime(817):     at java.lang.reflect.Method.invokeNative(Native Method)
11-28 15:46:50.943: ERROR/AndroidRuntime(817):     at java.lang.reflect.Method.invoke(Method.java:521)
11-28 15:46:50.943: ERROR/AndroidRuntime(817):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
11-28 15:46:50.943: ERROR/AndroidRuntime(817):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
11-28 15:46:50.943: ERROR/AndroidRuntime(817):     at dalvik.system.NativeStart.main(Native Method)
11-28 15:46:50.943: ERROR/AndroidRuntime(817): Caused by: java.lang.NullPointerException
11-28 15:46:50.943: ERROR/AndroidRuntime(817):     at unjustentertainment.com.MusicService.onCreate(MusicService.java:36)
11-28 15:46:50.943: ERROR/AndroidRuntime(817):     at android.app.ActivityThread.handleCreateService(ActivityThread.java:2959)

我的音乐服务类需要一个播放媒体播放器的路径。但有了这个新的意图，我不添加任何额外的内容，因为我只想显示 SongPlaying 类，就像我单击“正在播放”按钮之前一样

Answer 1

您可能没有检查 IplayerActivity.this 中 onCreate 方法内的捆绑包是否有 Extra，

否则，您需要包含更多信息，因为很难判断您的 NPE 来自何处。