ANDROID: Activity state after pressing the back button

Issue

Imagine you have the following sequence of activities:

Activity A -> Activity B -> Activity C

When you are on Activity C, pressing the native back button, takes you to Activity B. Now what is the state of Activity C? Is it still in memory or it has been finished?

If it is still in the memory, is there a way to resume the activity? Other than starting another instance of this activity...

I should add that this is the standard case where you do not use any flags including: FLAG_ACTIVITY_CLEAR_TOP

Solution

You might want to consider reading the official docs.

More specifically the part that answers your question:

When the user presses the Back button, the current activity is popped from the top of the stack (the activity is destroyed) and the previous activity resumes (the previous state of its UI is restored).

Now for your second question… you can keep reading the same page…

when you start an activity, you want to bring forward an existing instance of it (instead of creating a new instance on top of the back stack)

So if you read that… you will find…

You can do these things and more, with attributes in the manifest element and with flags in the intent that you pass to startActivity().

In this regard, the principal attributes you can use are:

taskAffinity launchMode allowTaskReparenting clearTaskOnLaunch alwaysRetainTaskState finishOnTaskLaunch

And the principal intent flags you can use are:

FLAG_ACTIVITY_NEW_TASK FLAG_ACTIVITY_CLEAR_TOP FLAG_ACTIVITY_SINGLE_TOP

Answered By - Martin Marconcini