Question

I have two activities a parent and a child activity but the child activity is also triggered by another activity. Now I want to return result from this child activity to the Parent activity ONLY when the child activity is triggered from this parent activity.

Is there any way the child can find out the caller activity (so that it does some calculations only for that caller activity). Is there any way I can avoid this:

intent.putExtra("caller", "MainActivity");
startActivity(intent);

I want this:

if (ParentActivity)
{  //do something and finish() }
if (AnotherActivity)
{  //do something more and finish() }

Answer 1

Yes you can do that by using startActivityForResult() from the Parent activity that you chose to be the one handling the results.

Launch an activity for which you would like a result when it finished.
When this activity exits, your onActivityResult() method will be
called with the given requestCode. Using a negative requestCode is the
same as calling startActivity(Intent) (the activity is not launched as
a sub-activity).

Basically in the Parent activity you can do:

Intent intent = ...
startActivityForResult(intent, SOME_UNIQUE_INT_CODE);

Then you have to define a method to handle the results which is onActivityResult()

protected void onActivityResult(int requestCode, int resultCode,
             Intent data) {
         if (requestCode == SOME_UNIQUE_INT_CODE) {
              // do something
         }
     }

Inside the child activity, you can set the result by using setResult(). There are two variants of this method one of them gives you the possibility to pass in some data.

Please, read the documentation to find more about how to use it.

EDIT:

You can use: getCallingActivity() from the called activity to find which is the parent activity but that only works if you used startActivityForResult.

Return the name of the activity that invoked this activity. This is
who the data in setResult() will be sent to. You can use this
information to validate that the recipient is allowed to receive the
data.

Note: if the calling activity is not expecting a result (that is it
did not use the startActivityForResult(Intent, int) form that includes
a request code), then the calling package will be null.