class AppProvider with ChangeNotifier {
  static List<CategoryModel> categoryModelList = [];
  late CategoryModel categoryModel;
  Future<void> getCategoryProduct() async {
    List<CategoryModel> list = [];
    QuerySnapshot querySnapshot =
        await FirebaseFirestore.instance.collection("homecategory").get();
    querySnapshot.docs.forEach(
      (categoryData) {
        categoryModel = CategoryModel(
          image: categoryData["image"],
          name: categoryData["name"],
        );
        list.add(categoryModel);
      },
    );
    categoryModelList = list;
    notifyListeners();
  }

  List<CategoryModel> get getCategoryModelList {
    return categoryModelList;
  }
}

Widget _buildBottomPart() { return Container( width: double.infinity, height: 240, child: Column( mainAxisAlignment: MainAxisAlignment.end, crossAxisAlignment: CrossAxisAlignment.start, children: [ Container( height: 240, child: ListView.builder( scrollDirection: Axis.horizontal, itemCount: AppProvider.getCategoryModelList.length, itemBuilder: (ctx, index) => _buildSingleCategory( name: AppProvider.getCategoryModelList[index].name, image: AppProvider.getCategoryModelList[index].image, ), ), ), ], ), ); }

CodePudding user response：

either create an instance from AppProvider like this:

AppProvider appProvider = AppProvider();
appProvider.getCategoryModelList.length

or define 'getCategoryModelList' as static List