更新 Provider 子类的属性

如何解决更新 Provider 子类的属性

这里有几个类。

abstract class Vehicle {
  Vehicle(this.owner);

  String owner;
}


class Car extends Vehicle {
  Car(String owner) : super(owner);
  int fule = 0;

  void fillFule(int fule) {
    this.fule += fule;
  }
}



class Cycle extends Vehicle {
  Cycle(String owner) : super(owner);
    
  int chainDurability = 50;

  void changeChain() {
    this.chainDurability = 50;
  }
}

还有一个提供者。

class VehicleProvider extends ChangeNotifier {
  List<Vehicle> vehicles = [];
}

更新Vehicle的属性很容易

class VehicleProvider extends ChangeNotifier {
  List<Vehicle> vehicles = [];
    
  /// I usually do that
  void changeOwner(int index,String newOwner) {
    vehicles[index].owner = newOwner;
    notifyListeners();
  }
}

但是如何更新 Car 或 Cycle 的属性？

我无法通过 Car 公开 Cycle 和 VehicleProvider 的控制器。因为会有很多 Vehicle 的子类。

所以我想手动调用 notifyListeners()，就像 setState() 一样。它有效，但似乎是反模式。

class VehicleProvider extends ChangeNotifier {
    
  ...
    
  /// I added empty notifyListeners.
  void doNotifyListeners() {
    notifyListeners();
  }
}

class CarCtrlPanel extends StatelessWidget {
  CarCtrlPanel(this.car);
  final Car car;

  @override
  Widget build(BuildContext context) {
    return Container(
      child: Column(
        children: [
          Text('${car.owner}s car'),Row(
            children: [
              Text('fule: ${car.fule}'),FlatButton(
                onpressed: () {
                  car.fillFule(10);
                    
                  /// And call it manually
                  Provider.of<VehicleProvider>(context,listen: false)
                      .doNotifyListeners();
                },child: Text('fill fule'),),],);
  }
}

class CycleCtrlPanel extends StatelessWidget {
  CycleCtrlPanel(this.cycle);
  final Cycle cycle;

  @override
  Widget build(BuildContext context) {
    return Container(
      child: Column(
        children: [
          Text('${cycle.owner}s cycle'),Row(
            children: [
              Text('chainDurability: ${cycle.chainDurability}'),FlatButton(
                onpressed: () {
                  cycle.changeChain();
                    
                  /// Same as above
                  Provider.of<VehicleProvider>(context,);
  }
}