类型“_Type”不是类型 'Widget?' 的子类型

Question

在我的代码中，消费者身份验证存在问题，我在这里发现了一个类似的问题，但与我的错误无关，我尝试了很多方法来解决它，有人可以帮忙吗？

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MultiProvider(
        providers: [
          ChangeNotifierProvider.value(value: Auth()),
          ChangeNotifierProxyProvider<Auth, ProductProvider>(
            update: (ctx, auth, previousprod) => ProductProvider(
                auth.token, previousprod == null ? [] : previousprod.items),
          ),
          ChangeNotifierProvider.value(
            value: Cart(),
          ),
          ChangeNotifierProvider.value(
            value: Order(),
          )
        ],
        child: Consumer<Auth>(
          builder: (ctx, auth, _) => MaterialApp(
            debugShowCheckedModeBanner: false,
            title: 'MyShop',
            theme: ThemeData(
                primarySwatch: Colors.purple,
                accentColor: Colors.deepOrange,
                fontFamily: 'Lato'),
            home: auth.isAuth ? ProductOverviewScreen : AuthScreen(),
            routes: {
              // '/':(ctx)=> ProductOverviewScreen(),
              ProductDetailScreen.routName: (ctx) => ProductDetailScreen(),
              CartScreen.routName: (ctx) => CartScreen(),
              OrderScreen.routName: (ctx) => OrderScreen(),
              ProductOverviewScreen.routName: (ctx) => ProductOverviewScreen(),
              UserProductsScreen.routName: (ctx) => UserProductsScreen(),
              EditProductScreen.routName: (ctx) => EditProductScreen(),
            },
          ),
        ));
  }
}

Answer 1

相信这是解决方法，只需复制粘贴并告诉我:)

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MultiProvider(
        providers: [
          ChangeNotifierProvider.value(value: Auth()),
          ChangeNotifierProxyProvider<Auth, ProductProvider>(
            update: (ctx, auth, previousprod) => ProductProvider(
                auth.token, previousprod == null ? [] : previousprod.items),
          ),
          ChangeNotifierProvider.value(
            value: Cart(),
          ),
          ChangeNotifierProvider.value(
            value: Order(),
          )
        ],
        child: Consumer<Auth>(
          builder: (ctx, auth, _) => MaterialApp(
            debugShowCheckedModeBanner: false,
            title: 'MyShop',
            theme: ThemeData(
                primarySwatch: Colors.purple,
                accentColor: Colors.deepOrange,
                fontFamily: 'Lato'),
            home: auth.isAuth ? ProductOverviewScreen() : AuthScreen(),
            routes: {
              // '/':(ctx)=> ProductOverviewScreen(),
              ProductDetailScreen.routName: (ctx) => ProductDetailScreen(),
              CartScreen.routName: (ctx) => CartScreen(),
              OrderScreen.routName: (ctx) => OrderScreen(),
              ProductOverviewScreen.routName: (ctx) => ProductOverviewScreen(),
              UserProductsScreen.routName: (ctx) => UserProductsScreen(),
              EditProductScreen.routName: (ctx) => EditProductScreen(),
            },
          ),
        ));
  }
}

类型“_Type”不是类型 'Widget?' 的子类型

type '_Type' is not a subtype of type 'Widget?'

dart

flutter

flutter-widget

相信这是解决方法，只需复制粘贴并告诉我:)