Flutter 仅在获取(读取)、Provider 时，Firestore 中的数据为空

我面对这个问题，结果只在UI中显示为"空"，我想不出解决的办法.我正在使用Provider 作为状态管理.作为后端的Firebase.

我只是在执行一个简单的操作，就是获取数据.

这是服务代码

Stream<List<CategoryModel>> getCateogoriesFromFirebase() {
  final categoryCollection =
      fireStoreInstance.collection('categories').snapshots();

  return categoryCollection.map((querySnapshots) {
    var categories = <CategoryModel>[];

    for (var singleCate in querySnapshots.docs) {
      CategoryModel categoryModel = CategoryModel.fromFirebase(singleCate);

      categories.add(categoryModel);
    }

    return categories;
  });
}

以下是控制器部分的代码

Stream<List<CategoryModel>> getCategoriesFiresotre() {
  return _dataBaseService.getCateogoriesFromFirebase();
}

以下是视图代码

SizedBox(

  height: 72,
  child: StreamBuilder(
      stream: Provider.of<HomeController>(
        context,
      ).getCategoriesFiresotre(),
      builder: (context, snapsshot) {
        if (snapsshot.data?.length == 0) {
          return Text('empty');
        }

        if (snapsshot.data != null) {
          return ListView.builder(
              shrinkWrap: true,
              physics: const BouncingScrollPhysics(),
              scrollDirection: Axis.horizontal,
              itemCount: snapsshot.data?.length,
              itemBuilder: (c, i) {
                return Container(
                  margin: const EdgeInsets.all(5),
                  height: 50,
                  width: 100,
                  color: Colors.blueGrey,
                  child: Center(
                    child: Text(
                        snapsshot.data?[i].category ?? 'Category'),
                  ),
                );
              });
        }
        return CircularProgressIndicator();
      }),
),

The output, In the UI is only the Text widget "Empty" I have checked the Firestore rules, They are all up to date.