Is this the right way to clean-up Fragment back stack when leaving a deeply nested stack?

Question

Well there are a few ways to go about this depending on the intended behavior, but this link should give you all the best solutions and not surprisingly is from Dianne Hackborn

http://groups.google.com/group/android-developers/browse_thread/thread/d2a5c203dad6ec42

Essentially you have the following options

• Use a name for your initial back stack state and use FragmentManager.popBackStack(String name, FragmentManager.POP_BACK_STACK_INCLUSIVE).
• Use FragmentManager.getBackStackEntryCount()/getBackStackEntryAt().getId() to retrieve the ID of the first entry on the back stack, and FragmentManager.popBackStack(int id, FragmentManager.POP_BACK_STACK_INCLUSIVE).
• FragmentManager.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE) is supposed to pop the entire back stack... I think the documentation for that is just wrong. (Actually I guess it just doesn't cover the case where you pass in POP_BACK_STACK_INCLUSIVE),

The other clean solution if you don't want to pop all stack entries...

getSupportFragmentManager().popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
getSupportFragmentManager().beginTransaction().replace(R.id.home_activity_container, fragmentInstance).addToBackStack(null).commit();

This will clean the stack first and then load a new fragment, so at any given point you'll have only single fragment in stack

Thanks to Joachim answer, I use the code to clear all back stack entry finally.

// In your FragmentActivity use getSupprotFragmentManager() to get the FragmentManager.

// Clear all back stack.
int backStackCount = getSupportFragmentManager().getBackStackEntryCount();
for (int i = 0; i < backStackCount; i++) {

    // Get the back stack fragment id.
    int backStackId = getSupportFragmentManager().getBackStackEntryAt(i).getId();

    getSupportFragmentManager().popBackStack(backStackId, 
        FragmentManager.POP_BACK_STACK_INCLUSIVE);

} /* end of for */

I have researched a lot for cleaning Backstack, and finally see Transaction BackStack and its management. Here is the solution that worked best for me.

 // CLEAR BACK STACK.
    private void clearBackStack() {
        final FragmentManager fragmentManager = getSupportFragmentManager();
        while (fragmentManager.getBackStackEntryCount() != 0) {
            fragmentManager.popBackStackImmediate();
        }
    }

The above method loops over all the transactions in the backstack and removes them immediately one at a time.

Note: above code sometime not work and i face ANR because of this code,so please do not try this.

Update below method remove all fregment of that "name" from backstack.

FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.popBackStack("name",FragmentManager.POP_BACK_STACK_INCLUSIVE);

• name If non-null, this is the name of a previous back state to look for; if found, all states up to that state will be popped. The
• POP_BACK_STACK_INCLUSIVE flag can be used to control whether the named state itself is popped. If null, only the top state is popped.

I'm using a similar code as those that use the while loop but I call the entry count in every loop... so I suppose it's somewhat slower

FragmentManager manager = getFragmentManager();
while (manager.getBackStackEntryCount() > 0){
        manager.popBackStackImmediate();
    }