flutter - 抽象类的 super 构造函数中的 undefined_named_pa​​rameter

Question

我是 Dart 和 Flutter 的新手，我一直在尝试创建两个类(SuccessState 和 ErrorState)来实现一个带有可选命名参数的抽象类 (DataState)。出于某种原因，每当我在 SuccessState 和 ErrorState 中调用 super 构造函数时，我都会在 SuccessState 构造函数中的“data”参数以及 ErrorState 构造函数中的“status”和“msg”参数上收到 undefined_named_pa​​rameter 错误。非常感谢任何输入，谢谢。

abstract class DataState<T> {
  final T? data;
  final int? status;
  final String? msg;

  const DataState({this.data, this.status, this.msg});
}

class SuccessState<T> implements DataState<T> {
  const SuccessState(T data) : super(data: data);

  @override
  noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
}

class ErrorState<T> implements DataState<T> {
  const ErrorState(int status, String msg) : super(status: status, msg: msg);

  @override
  noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
}

Answer 1

您想将 SuccessState 和 ErrorState 扩展到 DataState。

abstract class DataState<T> {
  final T? data;
  final int? status;
  final String? msg;

  const DataState({this.data, this.status, this.msg});
}

class SuccessState<T> extends DataState<T> {
  SuccessState(T data) : super(data: data);

  @override
  noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
}

class ErrorState<T> implements DataState<T> {
  const ErrorState(int status, String msg) : super();

  @override
  noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
}