Question

我正在尝试此代码

        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();

并且在mainactivity上我试着得到如下结果

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);
    }
}

但是我得到了一个runtimeException：当我点击我的listview

时，无法提供结果ResultInfo

这是我的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

任何帮助都会提前感谢

Answer 1

将Intent in = new Intent(getApplicationContext(), MainActivity.class);替换为Intent in = getIntent()，然后重试。

无法将结果ResultInfo从ListActivity传递到MainActivity

1 个答案: