flutter - 颤振底部导航栏在导航上消失

Question

我有一个包含 4 个项目的底部导航栏和一个带有 3 个路由器的顶部导航栏，这些路由器重定向到其中没有一个是底部导航栏的一部分的页面，我的底部导航栏工作正常，但是每当我使用顶部导航栏时，我的底部导航栏消失了，基本上我希望底部导航栏上的第一项包含我的顶部导航栏的所有 3 页，每当我使用顶部导航栏导航时，底部导航栏上的第一项保持选中状态。

    class _HomePageState extends State<HomePage> {
  PageController _pageController = PageController();
  List<Widget> _screens = [
    ProchaineState(),
    MesEncheres(),
    MesFavorisOn(
      arr: [],
    ),
    Autres(),
  ];
  int _selectedIndex = 0;
  void _onPageChanged(int index) {
    setState(() {
      _selectedIndex = index;
    });
  }

  void _onItemTapped(int selectedIndex) {
    _pageController.jumpToPage(selectedIndex);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      extendBody: true,
      body: PageView(
        controller: _pageController,
        children: _screens,
        onPageChanged: _onPageChanged,
      ),
      floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,
      floatingActionButton: Container(
        margin: EdgeInsets.only(
          top: 70.0,
        ),
        height: 72.0,
        width: 72.0,
        child: FloatingActionButton(
          backgroundColor: Colors.transparent,
          elevation: 0.0,
          onPressed: () {},
          child: Stack(
            children: [
              Image.asset(
                'assets/images/Ellipse 348.png',
              ),
              Container(
                margin: EdgeInsets.only(
                  left: 23.0,
                  top: 20.0,
                ),
                child: Image.asset(
                  'assets/images/Icon feather-shopping-cart.png',
                ),
              ),
            ],
          ),
        ),
      ),
      bottomNavigationBar: Container(
        height: 70.0,
        decoration: BoxDecoration(
          color: Colors.white,
          borderRadius: BorderRadius.only(
            topRight: Radius.circular(30),
            topLeft: Radius.circular(30),
          ),
          boxShadow: [
            BoxShadow(
              color: Colors.grey.withOpacity(0.8),
              spreadRadius: 10,
              blurRadius: 5,
              offset: Offset(0, 7),
            ),
          ],
        ),
        child: ClipRRect(
          borderRadius: BorderRadius.only(
            topLeft: Radius.circular(30.0),
            topRight: Radius.circular(30.0),
          ),
          child: BottomNavigationBar(
            onTap: _onItemTapped,
            selectedFontSize: 0,
            backgroundColor: Colors.white,
            showSelectedLabels: false,
            showUnselectedLabels: false,
            type: BottomNavigationBarType.fixed,
            items: [
              BottomNavigationBarItem(
                icon: _selectedIndex == 0
                    ? CircleAvatar(
                        backgroundImage: NetworkImage(
                          'https://lh3.googleusercontent.com/zXsTPqAQch7qsQdRqZal7Mm0Wmxev0X5SRedA0B7NVMi7oKcygrWKxLaPiZX7gYCNmcMdA=s42',
                        ),
                        child: Image.asset(
                          'assets/images/AccueilSelected.png',
                        ),
                      )
                    : Image.asset('assets/images/Accueil.png'),
                label: "",
              ),
              BottomNavigationBarItem(
                icon: _selectedIndex == 1
                    ? Container(
                        margin: EdgeInsets.only(
                          right: 42.0,
                        ),
                        child: CircleAvatar(
                          backgroundImage: NetworkImage(
                            'https://lh3.googleusercontent.com/zXsTPqAQch7qsQdRqZal7Mm0Wmxev0X5SRedA0B7NVMi7oKcygrWKxLaPiZX7gYCNmcMdA=s42',
                          ),
                          child: Stack(
                            children: [
                              Image.asset(
                                  'assets/images/Group 494Selected.png'),
                              Container(
                                margin: EdgeInsets.only(
                                  left: 19.0,
                                  // top: 0.8,
                                ),
                                child: Image.asset(
                                    'assets/images/Ellipse 341.png'),
                              ),
                            ],
                          ),
                        ),
                      )
                    : Container(
                        margin: EdgeInsets.only(
                          right: 42.0,
                        ),
                        child: Stack(
                          children: [
                            Image.asset('assets/images/Group 494.png'),
                            Container(
                              margin: EdgeInsets.only(
                                left: 19.0,
                                // top: 0.8,
                              ),
                              child:
                                  Image.asset('assets/images/Ellipse 341.png'),
                            ),
                          ],
                        ),
                      ),
                label: "",
              ),
              BottomNavigationBarItem(
                icon: _selectedIndex == 2
                    ? Container(
                        margin: EdgeInsets.only(
                          left: 38.0,
                        ),
                        child: CircleAvatar(
                          backgroundImage: NetworkImage(
                            'https://lh3.googleusercontent.com/zXsTPqAQch7qsQdRqZal7Mm0Wmxev0X5SRedA0B7NVMi7oKcygrWKxLaPiZX7gYCNmcMdA=s42',
                          ),
                          child: Image.asset(
                            'assets/images/Icon ionic-ios-heart-emptySelected.png',
                          ),
                        ),
                      )
                    : Container(
                        margin: EdgeInsets.only(
                          left: 38.0,
                        ),
                        child: Image.asset(
                            'assets/images/Icon ionic-ios-heart-emptyBlack.png'),
                      ),
                label: "",
              ),
              BottomNavigationBarItem(
                icon: _selectedIndex == 3
                    ? CircleAvatar(
                        backgroundImage: NetworkImage(
                          'https://lh3.googleusercontent.com/zXsTPqAQch7qsQdRqZal7Mm0Wmxev0X5SRedA0B7NVMi7oKcygrWKxLaPiZX7gYCNmcMdA=s42',
                        ),
                        child: Image.asset(
                          'assets/images/Icon open-menuSelected.png',
                        ),
                      )
                    : Image.asset(
                        'assets/images/Icon open-menu.png',
                        width: 24.0,
                        height: 21.0,
                      ),
                label: "",
              ),
            ],
          ),
        ),
      ),
    );
  }
}