Question

When I have two activities

Activity A, B;
// A stands for Login Screen
// B stands for Main Application Screen

Application starts with A, then user performs login and he will be pointed to B

When I launch B I add this flag to Intent Intent.FLAG_ACTIVITY_CLEAR_TOP but when I finish the B I expect it to be the last activity and to quit the application.

Instead of what I expected, A is brought to front, and user stills on Login Screen again.

Should I start A from B as startActivityForResult and use B as main activity of whole application ?

Or the flag is not working as it should be?

Answer 1

Don’t bother with intent flags. When activity A starts activity B after a successful login, just have A call finish().

An alternative, slightly more involved, approach is to make B your main activity and in B’s onCreate method, start activity A for a result, which should be some pass/fail flag. When Activity A finishes (either on a successful login, failure, or the user just quitting), activity B determines in onActivityResult whether to continue or to finish, based on the returned value. This works because, according to the docs:

As a special case, if you call startActivityForResult() with a requestCode >= 0 during the initial onCreate(Bundle savedInstanceState)/onResume() of your activity, then your window will not be displayed until a result is returned back from the started activity. This is to avoid visible flickering when redirecting to another activity.