Android - fragment back stack resulting into white screen

Question

I have five different fragments in my project, let's call them A...E. A and B are only visible for the user when he opens the app. Those are responsible for showing the loading screen (checking current login session) and the login screen itself. Fragment C ist the main screen of that application which the user can use to reach the other areas of the app. Because of that this, the fragments D and E got the "addToBackStack(String)" extra when the transaction have been created/commited.

My problem which is resulting into a blank screen, is when the user is opening D or E and goes back to C again. This action can lead to the blank screen for C the first time or redoing that step several times.

The relevant fragments C,D,E are using a view holder, databinding and recycler views. Each recycler view has multiple view types.

It seems like that onBackPressed to C is executing correctly but that C has been deleted from the cache or something similar.

Hope anyone can help me with that issue.

https://stackoverflow.com/questions/18305945/how-to-resume-fragment-from-backstack-if-exists please verify this for understanding the back-stack system — kautilya hari, Jun 08 '17 at 08:29
I already read that entry and didn't help me to solve my problem. — Mordag, Jun 08 '17 at 08:49

score 0 · Accepted Answer · answered Jun 08 '17 at 09:57

I found a possible solution for my problem. Still need to test this further but so far it seems to work:

private void showFragment(Fragment fragment, String tag, String backStackTag) {
    FragmentTransaction ft = fragmentManager.beginTransaction();

    if (backStackTag != null) {
        ft.addToBackStack(backStackTag);
    }

    switch (tag) {
        case "A":
        case "B":
            ft.replace(containerId, fragment, tag);
            break;
        case "C": {
            Fragment main = fragmentManager.findFragmentByTag("C");
            if (main != null) {
                ft.show(main);
            } else {
                ft.replace(containerId, fragment, tag);
            }
            break;
        }
        case "D":
        case "E": {
            Fragment main = fragmentManager.findFragmentByTag("C");
            ft.hide(main);
            ft.add(containerId, fragment, tag);
            break;
        }
        default:
            ft.add(containerId, fragment, tag);
            break;
    }

    ft.commit();
}

Android - fragment back stack resulting into white screen

1 Answers1