为什么 flutter Navigator 2.0 中没有触发 onPopPage？

Question

当按下后退按钮而不是更新状态和屏幕时，应用程序将退出。我从 Flutter Apperenties 复制了这个逻辑。同样的逻辑在另一个项目中运行良好。

我找不到错误。我尝试在 _handlePopPage 方法内部打印，但应用程序退出并且不会打印。我认为 onPopPage 没有被触发。

这是我的代码，

class AppRouter extends RouterDelegate
    with ChangeNotifier, PopNavigatorRouterDelegateMixin {
  @override
  final GlobalKey<NavigatorState> navigatorKey;
  final AppState appStateManager;
  final ProvinceProvider provinceProvider;
  AppRouter({
    Key? key,
    required this.appStateManager,
    required this.provinceProvider,
  }) : navigatorKey = GlobalKey<NavigatorState>() {
    appStateManager.addListener(notifyListeners);
    provinceProvider.addListener(notifyListeners);
  }
  @override
  void dispose() {
    appStateManager.removeListener(notifyListeners);
    provinceProvider.removeListener(notifyListeners);
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Navigator(
      key: navigatorKey,
      pages: [
        if (!appStateManager.isInitialized) SplashScreen.page(),
        if (appStateManager.isInitialized &&
            appStateManager.currentPage == CurrentPagePointer.dashboardScreen)
          DashboardScreen.page(),
        if (appStateManager.currentPage ==
            CurrentPagePointer.openeingInformationScreen)
          OpeningInformationScreen.page(),
        if (appStateManager.currentPage == CurrentPagePointer.rQ1aScreen)
          RQ1aScreen.page(),
        if (appStateManager.currentPage == CurrentPagePointer.rQ1bScreen)
          RQ1bScreen.page(),
        if (appStateManager.currentPage == CurrentPagePointer.rQ1cScreen)
          RQ1cScreen.page(),
        if (appStateManager.currentPage == CurrentPagePointer.rQ1dScreen)
          RQ1dScreen.page(),
        if (appStateManager.currentPage == CurrentPagePointer.rQ1eScreen)
          RQ1eScreen.page(),
        if (appStateManager.currentPage == CurrentPagePointer.thankYouScreen)
          ThankYouScreen.page(),
      ],
      onPopPage: _handlePopPage,
    );
  }

  bool _handlePopPage(Route<dynamic> route, result) {
    if (!route.didPop(result)) {
      return false;
    }
    if (route.settings.name == MaxMediaPages.openeingInformationScreen) {
      print(route.settings.name);
      appStateManager.setCurrentPage(CurrentPagePointer.dashboardScreen);
      provinceProvider.resetData();
    }
    if (route.settings.name == MaxMediaPages.thankYouScreen) {
      print(route.settings.name);
      appStateManager.setCurrentPage(CurrentPagePointer.dashboardScreen);
    }
    return true;
  }

  @override
  Future<void> setNewRoutePath(configuration) async {}
}

Answer 1

第一页必须仅为“SplashScreen.page(),”：无先前条件

Answer 2

您现在可能已经解决了这个问题，但是对于遇到相同问题的其他人，请检查您的 main.dart 或调用 MaterialApp （和 Router）的类。它必须有一个参数： backButtonDispatcher: RootBackButtonDispatcher(),

在我的例子中，它看起来像这样：

Widget build(BuildContext context) {
    return MultiProvider(
        providers: [
            ChangeNotifierProvider(
                create: (context) => _rallyManager,
            ),
            ChangeNotifierProvider(
                create: (context) => _positionManager,
            ),
            ChangeNotifierProvider(
                create: (context) => _appStateManager,
            )
        ],
        child: MaterialApp(
            title: 'MyApp',
            home: Router(
                routerDelegate: _appRouter,
                backButtonDispatcher: RootBackButtonDispatcher(),
            ),
        ),
    );
}