according to the document
The purpose of this function is to allow the called activity to send a hint about its state so that this basic activity can prepare for exposure. Calling this method does not guarantee that the called activity will be or will soon exit. This only indicates that it will display this activity window, and it has some data to prepare it.
so you can get data from another activity, even if it is still working. but for onActivityResult we get data when activity is completed.