FLAG_ACTIVITY_PREVIOUS_IS_TOP
If set and this intent is being used to launch a new activity from an existing one, the current activity will not be counted as the top activity for deciding whether the new intent should be delivered to the top instead of starting a new one. The previous activity will be used as the top, with the assumption being that the current activity will finish itself immediately.
developer에 이렇게 설명되어있어서 엑티비티 여러개 만들어서 테스트 해보는데 뭐가 다른지 모르겠네요 ㅠㅠ
어떻게 테스트 해봐야 가능할까요...