Coordinating activities in Android Application development
When one activity starts another, they both experience lifecycle transitions. One pauses and may stop, while the other starts up. On occasion, you may need to coordinate these activities, one with the other.
The order of lifecycle callbacks is well defined, particularly when the two activities are in the same process:
1. The current activity's onPause() method is called.
2. Next, the starting activity's onCreate(), onStart(), and onResume() methods are called in sequence.
3. Then, if the starting activity is no longer visible on screen, its onStop() method is called.