构建_InheritedProviderScope <DatabaseRepo>（值：<尚未加载>）时，引发了以下NoSuchMethodError：扑

Question

我正在使用Provider软件包来构建Flutter应用，以进行应用的状态管理。

这是我通过祖先小部件传递提供者的方式

@override
Widget build(BuildContext context) {
return MaterialApp(
  title: 'Flutter Ecommerce App',
  theme: ThemeData(
    visualDensity: VisualDensity.adaptivePlatformDensity,
    primaryColor: eDarkPrimaryColor,
    accentColor: eAccentColor,
    backgroundColor: eDefaultPrimaryColor,
    dividerColor: eDivideColor,
    scaffoldBackgroundColor: eLightPrimaryColor,
    textTheme:
        Theme.of(context).textTheme.apply(displayColor: ePrimaryTextColor),
  ),
  themeMode: ThemeMode.system,
  home: Provider<DatabaseRepo>(
    create: (context) => Database(),
    child: HomePageBase(
      database: Database(),
    ),
  ),
 );
}

这里是DatabaseRepo类。

abstract class DatabaseRepo {
  Stream<List<CategoryModel>> streamCategory();
  Stream<List<SubCategoryModel>> streamSubCategories(String categoryId);
}

class Database implements DatabaseRepo {
 @override
 Stream<List<CategoryModel>> streamCategory() =>
   FirebaseService.instance.collectionStream(
    path: APIPath.productsCategory(),
    builder: (data, id) => CategoryModel.fromMap(data, id),
  );

@override
Stream<List<SubCategoryModel>> streamSubCategories(String categoryId) =>
  FirebaseService.instance.collectionSubCategories(
    path: APIPath.productsSubCategory(categoryId),
    builder: (data) => SubCategoryModel.fromMap(data),
  );
}

这里是我用streamCategory()类调用的FirebaseService函数

Stream<List<T>> collectionStream<T>({
   @required String path,
   @required T builder(Map<String, dynamic> data, String documentId),
}) {
   final ref = Firestore.instance.collection(path).limit(6);
   final snapshots = ref.snapshots();
   snapshots.listen((event) => print('snapshsot ${event.documents}'));
    return snapshots.map(
      (snapshots) => snapshots.documents
       .map(
        (e) => builder(e.data, e.documentID),
      )
      .toList(),
   );
}

我真的不知道到底发生了什么。这是错误的详细信息：

这是我正在使用的依赖项。

cupertino_icons: ^0.1.3
font_awesome_flutter: ^8.8.1
cloud_firestore: ^0.13.5
provider: ^4.1.3
carousel_slider: ^2.2.1
sticky_headers: ^0.1.8