Question

如何在命名工厂构造函数中初始化超类的变量？这是我的示例代码：

class ClassA{
  final a;
  final b;

  ClassA({this.a, this.b});

}

class ClassB extends ClassA{
  final c;
  List <String> myList;

  ClassB({this.c,this.myList});


  factory ClassB.fromJson(json){
    var list = json["list"] as List;
    List<String> tempList = [];

    list.forEach((item)=>tempList.add(item));
    return ClassB(
      c: json["c"],
      myList: tempList
    );
  }


}

我不确定如何或在哪里确切地调用A类的超级构造函数，以便初始化其变量。

Answer 1

以下是致电super的方法：

class ClassA{
  final a;
  final b;

  ClassA({this.a, this.b});

}

class ClassB extends ClassA{
  final c;
  List <String> myList;

  ClassB({final a, final b, this.c,this.myList}) : super(a: a, b: b);

  factory ClassB.fromJson(json){
    var list = json["list"] as List;
    List<String> tempList = [];

    list.forEach((item)=>tempList.add(item));
    return ClassB(
      c: json["c"],
      myList: tempList
    );
  }
}

Dart在工厂命名构造函数中初始化超级构造函数

1 个答案: