如何在另一個變更通知程序 class 提供程序中使用來自一個變更通知程序 class 的方法

Question

我想在另一個提供者方法中使用 fetchdata() 並初始化變量。

Answer 1

var prevProvider = Provider.of<PrevProvider>(context, listen: false);
await prevProvider.fetchdata();

希望它會起作用

Answer 2

如果有人仍然對此有困難，那么也許這會有所幫助：

將一個提供者方法訪問到另一個提供者中：-

class 1：-

class OneState extends ChangeNotifier {

  List<Strings> _names = ["Alex", "Brad", "Carol"];
  List<GlobalKey> get names=> _names;

  updateNames(
      {required List<Strings> names}) {
    _names = names;

    notifyListners();
  }

}

class 2：-

class AnotherState extends ChangeNotifier {

  AnotherState({required this.watchOneStateProviderValue}); //<- Notice this.

  OneState watchOneStateProviderValue; //<- Notice this.

  late List<int> _iq;
  List<GlobalKey> get iq=> _iq;

  createIQFromNames() {

     // Getting names from another provider.
     List<String> names = watchOneStateProviderValue.names; //<- Notice this.

     _iq = [];
     for(var name in names){
       if(name == "Park Ju-hyun"){
         iq.add(99999);
       } else {
         iq.add(0);
       }
     }

     notifyListners();
  }
}

現在像這樣聲明提供者：-

final oneStateProvider =
    ChangeNotifierProvider((ref) => OneState());

final anotherStateProvider = ChangeNotifierProvider((ref) {
  // We use `ref.watch` to watch another provider, and we pass it the provider
  // that we want to consume. Here: oneStateProvider
  final CalendarPropertiesState watchCalendarPropertiesStateProviderValue =
      ref.watch(calendarPropertiesStateProvider);

  // We can then use the result to do something based on the value of `oneStateProvider`.
  return AnotherState(watchOneStateProviderValue: watchOneStateProviderValue);
});