StateNotifierProvider：是否可以使用单个 StateNotifierProvider 控制表单中不同小部件的值

Question

class SearchFilterModel {
  bool searchByDistance;
  bool filterByStatusOpen;
  String searchText;

  ...
}

class SearchFilterModelNotifier extends StateNotifier<SearchFilterModel> {
  SearchFilterModelNotifier() 
    : super(SearchFilterModel(
        searchByDistance: true,
        filterByStatusOpen: false,
        searchText: ''));

  void updateSearchByDistance(bool searchByDistance) {
    state.searchByDistance = searchByDistance;
  }

  void updateFilterByStatusOpen(bool filterByStatusOpen) {
    state.filterByStatusOpen = filterByStatusOpen;
  }

  void updateSearchText(String searchText) {
    state.searchText = searchText;
  }
}

final searchFilterModelNotifierProvider = StateNotifierProvider<SearchFilterModelNotifier, SearchFilterModel>((ref) => SearchFilterModelNotifier());

class SearchForm extends ConsumerWidget {
  @override
  Widget build(context, watch) {
    final searchFilterModelNotifier = watch(searchFilterModelNotifierProvider.notifier);
    final searchFilterModel = watch(searchFilterModelNotifierProvider);

    return Form(
      child: Column(
        children: [
          SwitchListTile(
            value: searchFilterModel.searchByDistance,
            onChanged: (bool value) => searchFilterModelNotifier.updateSearchByDistance(value),
            title: Text('Search by distance?')),
          SwitchListTile(
            value: searchFilterModel.filterByStatusOpen,
            onChanged: (bool value) => searchFilterModelNotifier.updateFilterByStatusOpen(value),
            title: Text('Filter by open status?')),
          // not even sure how to do the text one if using a TextFormField
          ]
        )
      );
    }
}

Okay with my project structured like this the values of the Switches aren't behaving as expected, their values aren't updating at all and I believe it's just that the widgets aren't rebuilding. I was able to make this work using a different state provider for each form field however when I have a lot of form fields it'd be way nicer to be able to have a single StateNotifierProvider that represents the entire form. Is this just something that's not possible?

Answer 1

The answer is to update the StateNotifier methods to something like

void updateSearchByDistance(bool searchByDistance) {
  state = SearchFilterModel(... searchByDistance: searchByDistance);
}