(Activity recreation): what to do with a backstack built on invalidated data?

Issue

What to do when:
1. The app uses a complex structure of Activities and Fragments
2. I return to a backgrounded application that has been (partially or not) destroyed in the meantime
3. It returns me to the last screen, which lies deep in the workflow
4. I need it to return to the first screen to reinitialize things (because it's complex and requires user interaction)

Just to be clear:
I am asking how to deal with the existing stack(s) of Activities and Fragments upon encountering this situation.
- action to take: launch an Intent? Just finish? Do something to held substructures and then finish?
- when to perform it - immediately in both Activity.onCreate and Fragment's empty constructor? Or are Activities sufficient?
- How best to detect it: all I've come up with so far is: binding to a Service that holds the necessary data/connection, and then asking if it's been initialized. But the binding finishes AFTER onResume.

I am not asking about anything UI-related.
I am not asking for a solution that will only work for one specific application, so don't ask for code.
If you see this question as vague, here is a one-sentence version: "How to dismiss the stack and return to the first screen?"

For details (as much, at least, as are relevant), see https://stackoverflow.com/questions/14650342.

Solution

If your goal is to dismiss all the activities and get back to your home/main activity then you can simply use:

Intent intent = new Intent(getApplicationContext(), Home.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);

This will clear all the activities on top of home and return you to the home screen.

Answered By - Anup Cowkur