Flutter 避免底部导航栏中的持久状态管理

Question

我正在使用库 persistent_bottom_nav_bar 并将 stateManagement 选项设置为 false，因为在页面中我希望每次进入页面时都使用未来的构建器。

问题是未来的构建器不再被调用，或者它被调用但页面仍然是以前的状态。

这是我的 PersistentTabView：

PersistentTabView(
  context,
  screens: _NavScreens(),
  items: _navBarsItems(),
  confineInSafeArea: true,
  backgroundColor: Colors.white,
  handleAndroidBackButtonPress: true,
  resizeToAvoidBottomInset: true,
  hideNavigationBarWhenKeyboardShows: true,
  hideNavigationBar: false,
  stateManagement: false,
  decoration: NavBarDecoration(
    border: Border(top: BorderSide(color: Colors.grey, width: 0.5))
  ),
  popAllScreensOnTapOfSelectedTab: true,
  navBarStyle: NavBarStyle.style6,
),

在示例中，我第一次进入页面时，将调用未来构建器并显示列表。如果我更改屏幕并返回到前一个屏幕，则未来的构建器将无法工作。

例子： https://imgur.com/a/jJWJPvU

Answer 1

我对 persistent_bottom_nav_bar 的 stateManagement 选项也有同样的问题。我将其描述为 false，它对状态没有影响所以我找到了另一个解决方案。我在我的项目中使用了 bloc 和提供程序。我用全局键解决了它，我将分享我的代码希望它有效。

 Map<int, GlobalKey<NavigatorState>> navigatorKeys = {
0: GlobalKey<NavigatorState>(),
1: GlobalKey<NavigatorState>(),
2: GlobalKey<NavigatorState>(),
3: GlobalKey<NavigatorState>(),
4: GlobalKey<NavigatorState>(),
         };

 late final List<Widget> _widgetOptions = 
  <Widget>[
  HomeView(companyId: 0, isDialogShow: isShow, bannerListModel: 
  bannerList, notificationModel: notificationList),
   CategoryTabView(),
     FavoritiesView(),
   BasketView(),
  ProfileView()
   ];

   @override
  Widget build(BuildContext context) {
  final basketProvider = Provider.of<BasketProvider>(context);
  final progressProvider = Provider.of<ProgressProvider>(context);
  final favoriteProvider = Provider.of<FavoriteProvider>(context);
  final bottomProvider = Provider.of<BottomNavBarProvider>(context);

return Scaffold(
  bottomNavigationBar: BottomNavigationBar(
    items: <BottomNavigationBarItem>[
      BottomNavigationBarItem(
          icon: Image.asset(
            ImageConstants.instance.homeIcon,
            color: context.colorScheme.error,
            scale: 3,
          ),
          label: ""),
        BottomNavigationBarItem(
          icon: Image.asset(
            ImageConstants.instance.categoryIcon,
            scale: 3,
          ),
          label: ""),
      BottomNavigationBarItem(
          icon: favoriteIcon(favoriteProvider), activeIcon: 
       favoriteIcon(favoriteProvider), label: ""),
      BottomNavigationBarItem(
          icon: badgeBasket(basketProvider, false), activeIcon: 
      badgeBasket(basketProvider, true), label: ""),
      BottomNavigationBarItem(
          icon: Image.asset(
            ImageConstants.instance.profileIcon,
            scale: 3,
          ),
          activeIcon: Image.asset(
            ImageConstants.instance.profileRedIcon,
            scale: 3,
          ),
          label: ""),
       ],
        currentIndex: bottomProvider.selectedIndex,
        onTap: bottomProvider.onItemTapped,
       ),
      body: buildNavigator(bottomProvider),
       );
         }

   buildNavigator(BottomNavBarProvider bottomProvider) {
   return Navigator(
    key: navigatorKeys[bottomProvider.selectedIndex],
     onGenerateRoute: (RouteSettings settings) {
     return MaterialPageRoute(builder: (_) => 
     _widgetOptions.elementAt(bottomProvider.selectedIndex));
     },
     );
     }
    }

     //this my provider

class BottomNavBarProvider with ChangeNotifier {
  int _selectedIndex = 0;
  int get selectedIndex => _selectedIndex;

  set selectedIndex(int index) {
    _selectedIndex = index;
    notifyListeners();
  }

  void onItemTapped(int index) {
    selectedIndex = index;
    notifyListeners();
  }
}

使用全局键方法，您可以使用静态底部导航栏，并且可以避免持久状态管理。希望它对您有所帮助。