set TextField value with FutureProvider

textField.dart

final sampleState = FutureProvider.autoDispose<HogeState>((ref) async {
  return HogeState( userName: "demo");
});


class LoginPage extends ConsumerWidget {

  final TextEditingController _usernameController = TextEditingController();

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    AsyncValue<HogeState> vm = ref.watch(sampleState);
    return vm.when(
        data: (data) {
          if (data.userName != null) _usernameController.text = data.userName!;
          return Scaffold(
              body: TextField(
                controller: _usernameController,
              );
        },
        loading: () => const CircularProgressIndicator(),
        error: (err, stack) => Text('Error: $err'));
  }
}