flutter - 使用 Flutter BottomNavigationBar 重建相同的选项卡

Question

我对 Flutter BottomNavigationBar 有疑问。我用 3 个项目构建了一个 BottomNavigationBar，完整的代码是

class TabPage extends StatefulWidget {
  @override
  _TabPageState createState() => _TabPageState();
}

class _TabPageState extends State<TabPage> {
  int _currentIndex = 0;

  final Map<int, Widget> _routes = <int, Widget>{
    0: MainTab(),
    1: NotificationTab(),
    2: BlocProvider(
      create: (context) => ProfileBloc(DataProvider()),
      child: ProfileTab(),
    ),
  };

  void _onTabTapped(int index) {
    setState(() {
      _currentIndex = index;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      bottomNavigationBar: BottomNavigationBar(
        showUnselectedLabels: false,
        currentIndex: _currentIndex,
        type: BottomNavigationBarType.fixed,
        onTap: _onTabTapped,
        items: [
          BottomNavigationBarItem(
            icon: Icon(
              Icons.language,
            ),
            label: AppLocalizations.of(context).translate("home"),
          ),
          BottomNavigationBarItem(
            icon: Icon(
              Icons.notifications,
            ),
            label: AppLocalizations.of(context).translate("notification"),
          ),
          BottomNavigationBarItem(
            icon: Icon(
              Icons.person,
            ),
            label: AppLocalizations.of(context).translate("profile"),
          )
        ],
      ),
      body: _routes[_currentIndex],
    );
  }
}

如果我从一个选项卡切换到另一个选项卡，一切正常，问题是如果用户点击当前选定的选项卡，该选项卡不会重新加载。第一个选项卡是一个带有 WebView 的小部件，所以我希望用户返回到 initialUrl，即使他已经在该选项卡上。似乎点击当前选择的选项卡没有任何效果。有没有办法重建后代小部件？

class MainTab extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: WebView(
        initialUrl: "https://www.google.com/",
        javascriptMode: JavascriptMode.unrestricted,
      ),
    );
  }
}

Answer 1

  final Map<int, Widget> _routes = <int, Widget>{
    0: MainTab(key : UniqueKey()),    // add key to every widget and pass it to super constructor.
    1: NotificationTab(key : UniqueKey()),
    2: BlocProvider(
      create: (context) => ProfileBloc(DataProvider()),
      child: ProfileTab(key : UniqueKey()),
    ),
  };