Flutter-使用MaterialPageRoute

Question

我正在学习在Flutter应用中使用与Firestore数据库通信的提供程序。
最初，该应用程序从Firestore集合的Listview小部件的ProductPage中加载了我的文档，然后在点击ListTile时可以编辑或删除该文档。另外，应用栏上有一个按钮，用户可以从中添加产品。很好。
然后，我向该应用添加了身份验证流程，该流程目前有效。但是要听整个应用程序中的authChanges，我必须从main.dart页面更改初始提供程序的工作方式。

我从

更改了代码

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    final firestoreService = FirestoreService();
    return MultiProvider(
      providers: [
        ChangeNotifierProvider( create: (context)=> ProductController(),),
        StreamProvider(create: (context) => firestoreService.fetchAllProducts())
      ],

          child: MaterialApp(
        title: 'Flutter Demo',
        theme: ThemeData(

          primarySwatch: Colors.blue,

          visualDensity: VisualDensity.adaptivePlatformDensity,
        ),
        home: Authenticate(),
      ),
    );
  }
}

并将其更改为： Main.dart代码：

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return StreamProvider<User>.value(
      value: AuthService().user,
      child: MaterialApp(
        title: 'Flutter Demo',
        theme: ThemeData(
          primarySwatch: Colors.blue,
          visualDensity: VisualDensity.adaptivePlatformDensity,
        ),
        home: Wrapper(),
      ),
    );
  }
}

我设法将所有内容连接在一起，以使用户在身份验证后即可访问产品。
正在按预期检索产品，但是，现在尝试导航到editPage

Navigator.of(context).push(
               CupertinoPageRoute(
                 builder: (context) => EditProduct(),
               ),

或转到新产品页面

ListView.builder(
             itemCount: products.length,
             itemBuilder: (context, index) {
               return ListTile(
                 title: Text(products[index].productName),
                 trailing: Text(products[index].price.toString()),
                 onTap: () {
                   **Navigator.of(context).push(
                     MaterialPageRoute(

                       builder: (BuildContext context) => EditProduct(products[index])**,
                     ),
                   );
                 },
               );
             })

，引发错误

Error: Could not find the correct Provider<ProductController> above this EditProduct Widget

Wrapper.dart代码：

class Wrapper extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final firestoreService = FirestoreService();
    final user = Provider.of<User>(context);

    //return either Products Page or Authentication Page

    if (user == null) {
      return Authenticate();
    }
     else {
      // return StreamProvider(
      //   create: (context) => firestoreService.fetchAllProducts(),
      //   child: Products(),
      // );
      return  MultiProvider(
      providers: [
        ChangeNotifierProvider<ProductController>( create: (context)=> ProductController(),),
        StreamProvider(create: (context) => firestoreService.fetchAllProducts())
      ],
      child: Consumer<ProductController>(builder: (context, provider, child) =>Products()) ,
      );

    }
  }
}

产品页面：

  @override
  Widget build(BuildContext context) {
    final products = Provider.of<List<Product>>(context);
    return Scaffold(
      appBar: AppBar(
              ...button that leads to editPage..
              Navigator.of(context).push(
                CupertinoPageRoute(
                  builder: (context) => EditProduct(),
                ),
              );
            },
          ),
        ],
      ),
      body:
          ListView.builder(
              itemCount: products.length,
              itemBuilder: (context, index) {
                return ListTile(
                  title: Text(products[index].productName),
                  trailing: Text(products[index].price.toString()),
                  onTap: () {
                    Navigator.of(context).push(
                      MaterialPageRoute(

                        builder: (BuildContext context) => EditProduct(products[index]),
                      ),
                    );
                  },
                );
              })

    );
  }
}

“编辑/添加产品页面”构建器

  Widget build(BuildContext context) {
    final productController = Provider.of<ProductController>(context);
    return Scaffold(.....more widgets....);