getAllValues method Null safety

Future<List> getAllValues({bool byGroup = true})

Implementation

Future<List> getAllValues({bool byGroup = true}) async {
  List resultList = List.empty(growable: true);
  var values = listControllers.map((e) {
    switch (e.isMultipleSelection && byGroup) {
      case true:
        return [e.selectedItem];
      default:
        return e.selectedItem;
    }
  }).where((v) {
    if (v != null) {
      if (v is List && v.isNotEmpty) {
        return true;
      } else {
        return true;
      }
    }
    return false;
  }).toList();
  for (var v in values) {
    if (v is List)
      resultList.addAll(v);
    else {
      if (v != null) resultList.add(v);
    }
  }

  return resultList;
}