list access outside provider class - flutter

Question

My problem is that when I access list under consumer and show into text widget it shows data. but when I use same list in initstate it shows null even when I use same list before return in consumer it shows null.
This is view:
class FilterView extends StatefulWidget {
const FilterView({super.key});
#override
State<FilterView> createState() => _FilterViewState();
}
class _FilterViewState extends State<FilterView> {
CategoryViewModel categoryViewModel = CategoryViewModel();
List<Categories>? categories = [];
#override
void initState() {
// categoryViewModel.fetchCategoryyListApi();
context.read<CategoryViewModel>().fetchCategoryyListApi();
// getList();
print("In filter initstate");
print(
"categoty List :${context.read<CategoryViewModel>().categoriess.length}");
getList();
super.initState();
}
getList() {
Provider.of<CategoryViewModel>(context, listen: false)
.categoriess
.map((category) {
return checkBoxes.add(CheckBoxSettings(title: category.title!));
});
print("checkBoxxxxxxxxxx: ${checkBoxes.length}");
}
**This is categoryviewModel:**
class CategoryViewModel extends ChangeNotifier {
List<Categories> categoriess = [];
final _myRepo = CategoryRepository();
Future<void> fetchCategoryyListApi() async {
_myRepo.fetchCategoryList().then((value) {
categoriess = value.categories!;
notifyListeners();
print(categoriess);
}).onError((error, stackTrace) {
print(error.toString());
});
}
}