How to return a result (startActivityForResult) from a TabHost Activity?

Question

I have 3 classes in my example: Class A, the main activity. Class A calls a startActivityForResult:

Intent intent = new Intent(this, ClassB.class);
startActivityForResult(intent, "STRING");

Class B, this class is a TabActivity:

Intent intent = new Intent(this, ClassC.class);
tabHost.addTab...

Class C, this class is a regular Activity:

Intent intent = this.getIntent();
intent.putExtra("SOMETHING", "EXTRAS");
this.setResult(RESULT_OK, intent);
finish();

onActivityResult is called in Class A, but the resultCode is RESULT_CANCELED instead of RESULT_OK and the returned intent is null. How do I return something from the Activity inside a TabHost?

I realize that the problem is that my Class C is actually running inside of Class B, and Class B is what is returning the RESULT_CANCELED back to Class A. I just don't know a work around yet.

Answer 1

Oh, god! After spending several hours and downloading the Android sources, I have finally come to a solution.

If you look at the Activity class, you will see, that finish() method only sends back the result if there is a mParent property set to null. Otherwise the result is lost.

public void finish() {
 if (mParent == null) {
 int resultCode;
 Intent resultData;
 synchronized (this) {
 resultCode = mResultCode;
 resultData = mResultData;
 }
 if (Config.LOGV) Log.v(TAG, "Finishing self: token=" + mToken);
 try {
 if (ActivityManagerNative.getDefault()
 .finishActivity(mToken, resultCode, resultData)) {
 mFinished = true;
 }
 } catch (RemoteException e) {
 // Empty
 }
 } else {
 mParent.finishFromChild(this);
 }
}

So my solution is to set result to the parent activity if present, like that:

Intent data = new Intent();
 [...]
if (getParent() == null) {
 setResult(Activity.RESULT_OK, data);
} else {
 getParent().setResult(Activity.RESULT_OK, data);
}
finish();

I hope that will be helpful if someone looks for this problem workaround again.

• CQM: I posted a hacky solution here, its simple and involves a transparent activity with no contents - it gets normal lifecycle functions and makes everything easier. stackoverflow.com/questions/7812120/…
• skygeek: I used your solution, still my code is not catching the onactivityresult method when coming back. please help me.. do i need to use any thing else?
• alex.p: Why is returning a result in an Activity not documented anywhere in the API guides, struck me as odd.
• Arash Afsharpour: thank you for your awesome job, just one thing, I wanna use this method in my onBackPressed override method too, but I Can't, do you know why? I cant use finish() in onBack and when I don't use its data and result code will be null in the A activity, do you know how can I Do such thing?

Answer 2

http://tylenoly.wordpress.com/2010/10/27/how-to-finish-activity-with-results/

With a slight modification for "param_result"

/* Start Activity */
public void onClick(View v) {
 Intent intent = new Intent(Intent.ACTION_VIEW);
 intent.setClassName("com.thinoo.ActivityTest", "com.thinoo.ActivityTest.NewActivity");
 startActivityForResult(intent,90);
}
/* Called when the second activity's finished */
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
 switch(requestCode) {
 case 90:
 if (resultCode == RESULT_OK) {
 Bundle res = data.getExtras();
 String result = res.getString("param_result");
 Log.d("FIRST", "result:"+result);
 }
 break;
 }
}
private void finishWithResult()
{
 Bundle conData = new Bundle();
 conData.putString("param_result", "Thanks Thanks");
 Intent intent = new Intent();
 intent.putExtras(conData);
 setResult(RESULT_OK, intent);
 finish();
}

• Afzaal Ahmad Zeeshan: Simple, setResult was the main thing. Set it to something, or a value for example RESULT_OK and you are good to go; setResult(RESULT_OK);. Helped me, +1

Answer 3

Intent.FLAG_ACTIVITY_FORWARD_RESULT?

If set and this intent is being used to launch a new activity from an existing one, then the reply target of the existing activity will be transfered to the new activity.

Answer 4

You could implement a onActivityResult in Class B as well and launch Class C using startActivityForResult. Once you get the result in Class B then set the result there (for Class A) based on the result from Class C. I haven't tried this out but I think this should work.

Another thing to look out for is that Activity A should not be a singleInstance activity. For startActivityForResult to work your Class B needs to be a sub activity to Activity A and that is not possible in a single instance activity, the new Activity (Class B) starts in a new task.

• Cameron McBride: Since Class B is a TabActivity and Class C is a Tab in that activity you cannot do a startActivityForResult in Class B. None of my activities are Single Instance Activities.

Answer 5

For start Activity 2 from Activity 1 and get result, you could use startActivityForResult and implement onActivityResult in Activity 1 and use setResult in Activity2.

Intent intent = new Intent(this, Activity2.class);
intent.putExtra(NUMERO1, numero1);
intent.putExtra(NUMERO2, numero2);
//startActivity(intent);
startActivityForResult(intent, MI_REQUEST_CODE);