Android fragments navigation and backstack

Question

I have a header bar (kinda like menu) and 4 fragments (MAIN, A, B, C) from which the MAIN should be \'main/root\' fragment for backstack.

Problem i have is when user

Answer 1

Your stack must contains 2 fragments at maximum

Main is visible Main is onBackstack / AorBorC is visible. User click on back ==> Main is visible. User click on back ==> application end

I suppose A / B / C are displayed in the same view so in this case,

When user click on your Menu, you have to check if A/ B / C is currently displayed and replace it by the one selected by the user.

private void displayFragment(Fragment pFragment) {
    Fragment fr = getSupportFragmentManager()
            .findFragmentById(R.id.main_fl_fragmentcontainer);        
    FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
    ft.replace(R.id.main_fl_fragmentcontainer, pFragment);
    if (_CurrentFragment == _Frag_Main) {
        ft.addToBackStack(null);
    }
    ft.commit();    
    _CurrentFragment = pFragment;
}

can override OnBackPressed method of your activity.