Two Activity Life Cicle....

First Activity : A1
Second Activity : A2

OnStart......

A1 OnCreate -> A1 OnStart -> A1 OnResume

First Activity calls Second Activity

A1 OnPause -> A2 OnCreate -> A2 OnStart -> A2 OnResume -> A1 OnStop -> A1 OnDestroy

Second Activity Destroy...

A2 OnPause -> A2 OnStop -> A2 OnDestroy

But When Second Activity calls First Activity, Two Activity alives.

A2 OnPause -> A1 OnStart -> A1 OnResume -> A2 OnStop -> A2 OnDestroy