未能從ListActivity交付結果ResultInfo到MainActivity

我想這個代碼在mainactivity未能從ListActivity交付結果ResultInfo到MainActivity

 public void onItemClick(AdapterView<?> parent, View view, int position, 
       long id) { 
      //getting listitem index 
      int songIndex = position; 
      // Starting new intent 
      Intent in = new Intent(getApplicationContext(), MainActivity.class); 
      //sending songIndex to playactivity 
      in.putExtra("songIndex", songIndex); 

      setResult(100, in); 
      //closing PlayListView 
      finish();

，我設法得到如下結果

protected void onActivityResult(int requestCode, int resultCode, Intent data){ 
    super.onActivityResult(requestCode, resultCode, data); 
    if(resultCode == 100){ 
     currentSongIndex = data.getExtras().getInt("songIndex"); 
     //play selected song 
     playSong(currentSongIndex); 
    } 
}

，但我得到一個RuntimeException：不提供結果ResultInfo當我點擊我的列表視圖

這裏是我的logcat

01-14 21:13:09.360: I/dalvikvm-heap(14399): Grow heap (frag case) to 4.254MB for 1127536-byte allocation 
01-14 21:13:11.642: I/Choreographer(14399): Skipped 45 frames! The application may be doing too much work on its main thread. 
01-14 21:13:14.440: I/Choreographer(14399): Skipped 63 frames! The application may be doing too much work on its main thread. 
01-14 21:13:15.946: I/Choreographer(14399): Skipped 58 frames! The application may be doing too much work on its main thread. 
01-14 21:13:17.350: W/dalvikvm(14399): threadid=1: thread exiting with uncaught exception (group=0x40a71930) 
01-14 21:13:17.550: E/AndroidRuntime(14399): FATAL EXCEPTION: main 
01-14 21:13:17.550: E/AndroidRuntime(14399): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=100, result=100, data=Intent { cmp=com.example.mediaplayer/.MainActivity (has extras) }} to activity {com.example.mediaplayer/com.example.mediaplayer.MainActivity}: java.lang.NullPointerException 
01-14 21:13:17.550: E/AndroidRuntime(14399): at android.app.ActivityThread.deliverResults(ActivityThread.java:3319) 
01-14 21:13:17.550: E/AndroidRuntime(14399): at android.app.ActivityThread.handleSendResult(ActivityThread.java:3362) 
01-14 21:13:17.550: E/AndroidRuntime(14399): at android.app.ActivityThread.access$1100(ActivityThread.java:141) 
01-14 21:13:17.550: E/AndroidRuntime(14399): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1282) 
01-14 21:13:17.550: E/AndroidRuntime(14399): at android.os.Handler.dispatchMessage(Handler.java:99) 
01-14 21:13:17.550: E/AndroidRuntime(14399): at android.os.Looper.loop(Looper.java:137) 
01-14 21:13:17.550: E/AndroidRuntime(14399): at android.app.ActivityThread.main(ActivityThread.java:5041) 
01-14 21:13:17.550: E/AndroidRuntime(14399): at java.lang.reflect.Method.invokeNative(Native Method) 
01-14 21:13:17.550: E/AndroidRuntime(14399): at java.lang.reflect.Method.invoke(Method.java:511) 
01-14 21:13:17.550: E/AndroidRuntime(14399): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
01-14 21:13:17.550: E/AndroidRuntime(14399): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
01-14 21:13:17.550: E/AndroidRuntime(14399): at dalvik.system.NativeStart.main(Native Method) 
01-14 21:13:17.550: E/AndroidRuntime(14399): Caused by: java.lang.NullPointerException 
01-14 21:13:17.550: E/AndroidRuntime(14399): at com.example.mediaplayer.MainActivity.playSong(MainActivity.java:208) 
01-14 21:13:17.550: E/AndroidRuntime(14399): at com.example.mediaplayer.MainActivity.onActivityResult(MainActivity.java:195) 
01-14 21:13:17.550: E/AndroidRuntime(14399): at android.app.Activity.dispatchActivityResult(Activity.java:5293) 
01-14 21:13:17.550: E/AndroidRuntime(14399): at android.app.ActivityThread.deliverResults(ActivityThread.java:3315) 
01-14 21:13:17.550: E/AndroidRuntime(14399): ... 11 more

任何幫助將很多提前

來源

2014-01-31 Arturkamz

你也可以用你的playSong方法，這似乎是造成問題的原因 –

被apprecaited感謝取代Intent in = new Intent(getApplicationContext(), MainActivity.class);與Intent in = getIntent()，然後再試一次。

來源

2014-01-31 08:18:25

未能從ListActivity交付結果ResultInfo到MainActivity

回答

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