Android back button results in blank screen: can't block with popscope

[BarryCarlyon]

Package Version (from pubspec.yaml): persistent_bottom_nav_bar: ^5.0.0

Bug Description

If you navigate backwards from the home page of an app using the android back button you get black screen Press it again goes to another app/home page as expected.

The black screen shouldn't exist

Additionally, PopScope would be used to block the back button functioning and it doesn't when you wrap persistennav in a PopScope

To Reproduce

Steps to reproduce the behavior:

1. Launch you app
2. Use the Android back button, either hardward or software versions
3. Be pressnted with a blank page

This can result in an error message/console error messages as it's a totally unexpected state

as per my rubber ducking in https://github.com/jb3rndt/PersistentBottomNavBarV2/issues/137#issuecomment-2032944561

Expected behavior

• PopScope to work to prevent back "leaving" the app.
• If you navigate back without popscope it goes where it's supposed to not a blank page

Code to reproduce

This will block back working from the home page

    return ChangeNotifierProvider(
        create: (context) => ApiService(),
        child: PopScope(
            canPop: false,
            child: HomePageBuild()
        )
    );

This does not:

HomePageBuild in this case is my first tab in buildTabs.

    return ChangeNotifierProvider(
        create: (context) => ApiService(),
        child: PopScope(
            canPop: false,
            child: PersistentTabView(
          tabs: _buildTabs(),

          navBarOverlap: const NavBarOverlap.none(),
          navBarBuilder: (navBarConfig) => Style3BottomNavBar(
            navBarConfig: navBarConfig,
            navBarDecoration: const NavBarDecoration(
              color: superdarkRed,
            ),
          ),
          backgroundColor: superdarkRed,
        )
      )
    );

With or without popscope the blank page occurs

    return ChangeNotifierProvider(
      create: (context) => ApiService(),
      child: PersistentTabView(
        tabs: _buildTabs(),

        navBarOverlap: const NavBarOverlap.none(),
        navBarBuilder: (navBarConfig) => Style3BottomNavBar(
          navBarConfig: navBarConfig,
          navBarDecoration: const NavBarDecoration(
            color: superdarkRed,
          ),
        ),
        backgroundColor: superdarkRed,
      )
    );

Screenshots

After hitting the back soft key on the android "remote control" so a physical pixel 6 device here

If I hot reload/hit sync files I can force this error, if I'm on the blank page.

[BarryCarlyon]

I added:

    PersistentTabController _controller = PersistentTabController(initialIndex: 0);
    _controller.addListener(() {
      debugPrint('we be navin');
    });

snip

      child: PersistentTabView(
        controller: _controller,

And I don't get a "we be naving" when we go to the blank screen

[jb3rndt]

Hi, thank you for providing all the information. I'm pretty sure I finally found the issue. When migrating the internal WillPopScope to PopScope, the final navigator pop (which causes the black page) does not minimize the app like it used to when returning true from WillPopScope. I just released version 5.2.0 which should contain the fix. Now, a PopScope with canPop: false that wraps the PersistentTabView should also work. Feel free to check it out, I will keep this open for now in case there are still issues with that.

[BarryCarlyon]

Without popscope: we navigated out of the app and no blank screen With popscope: navigation was blocked out of the app and no blank screen

Looks fixed to me!