Android: Failure delivering result ResultInfo

问题:

I have an Activity A in TabHost, A startActivityForResult(B) then B startActivityForResult(C).
The problem I meet is that:
In C when I setResult(RESULT_OK, intent), occur

java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=0, result=-1, data=Intent { (has extras) }} to activity {com.hackingtrace.vancexu/com.hackingtrace.vancexu.task.B}: java.lang.NullPointerException 

In B, I start C by

setTimeButton.setOnClickListener(new View.OnClickListener() {          public void onClick(View view) {             Intent i = new Intent(view.getContext(), TaskTimeSet.class);             i.putExtra(TasksDbAdapter.KEY_ROWID, mRowId);             Calendar c = Calendar.getInstance();             Date d = c.getTime();                            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");             String now = sdf.format(d);             i.putExtra("date", now);              startActivityForResult(i, ACTIVITY_EDIT_TIME);         } 

and in C, I setResult by

confirmBtn.setOnClickListener(new OnClickListener() {          public void onClick(View v) {             // TODO Auto-generated method stub             Intent intent = new Intent();             intent.putExtra("date", resultDate);              int h = timePicker.getCurrentHour();             int m = timePicker.getCurrentMinute();             String time = "" +h+":"+m;             Log.d(TAG, time);             intent.putExtra("time", time);              setResult(RESULT_OK, intent);             finish();         }     }); 

then in B I receive the result by

protected void onActivityResult(int requestCode, int resultCode,         Intent intent) {     Log.d(TAG, "I am in " + requestCode + resultCode);     super.onActivityResult(requestCode, resultCode, intent);     if (requestCode == ACTIVITY_EDIT_TIME) {         if (resultCode == RESULT_OK) {             Log.d(TAG, "OK time set");             String[] dateArr = intent.getStringExtra("date").split("-");             String[] timeArr = intent.getStringExtra("time").split(":");             int year = Integer.parseInt(dateArr[0]);             int month = Integer.parseInt(dateArr[1]);             int day = Integer.parseInt(dateArr[2]);             int hour = Integer.parseInt(timeArr[0]);             int minute = Integer.parseInt(timeArr[1]);             Log.d(TAG, ""+year+month+day+hour+minute);                       }     } } 

But I never get the "Log.d(TAG, ""+year+month+day+hour+minute);" run normally.

I have tried:
1:

if (getParent() == null) {                 setResult(Activity.RESULT_OK, intent);             }             else {                 getParent().setResult(Activity.RESULT_OK, intent);             } 

not work :(
2:

i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); 

the error "java.lang.RuntimeException" not occur, but the requestCode and resultCode is 0 always.

回答1:

In C I putExtra 2 string (resultDate and time), but I miss the point that resultDate may not be initialized when it is be put into intent. So I got the Error: java.lang.NullPointerException.

回答2:

It looks like your Activity B is getting destroyed before C returns. One thing you can check is the "Dev Tools" app (It's among the app icons on most emulators and devices and in Settings on Ice Cream Sandwich labeled as "Developer Options") to make sure that the "Don't keep activities" option is not checked.

One thing you can do to verify that B is getting destroyed is to put a Log statement in Activity B's onCreate method. Then, when Activity C is launched from B, exit C by pushing the hardware Back button. This will destroy C (provided you haven't overridden the Back button), but it will not call B's onCreate unless B has been destroyed.

文章来源: Android: Failure delivering result ResultInfo