dart - Flutter getter 没有为类指定，当它被指定时

Question

我来了

[dart] The getter 'currentPickup' isn't defined for the class PickupEvent[undefined_getter]

event.currentPickup 出错:

import 'dart:async';

import 'package:bloc/bloc.dart';

import 'pickup.dart';
import '../../../models/models.dart';

class PickupBloc extends Bloc<PickupEvent, PickupState> {

  @override
  Stream<PickupState> mapEventToState(PickupState state, PickupEvent event) async* {
    if (state.isNotRunning) {
      stopwatch.start();
      timer = new Timer.periodic(new Duration(milliseconds: 200), updateTime);
      yield PickupState.running();
    }

    if (state.isRunning) {
      stopwatch.stop();
      timer.cancel();

      _pushPickup(event.currentPickup);

      yield PickupState.done();
    }
  }

当在 PickupEvent 类中指定 getter 并在pickup.dart 中正确导入时。

import '../../../models/models.dart';

abstract class PickupEvent {}

class ButtonPressed extends PickupEvent {
  final PickupModel currentPickup;

  ButtonPressed({
    @required this.currentPickup
  });
}

知道是什么原因造成的吗？

Answer 1

错误信息是正确的。 ButtonPressed 有这样的 getter，但 PickupEvent 没有。

您可以向基类添加抽象 getter

abstract class PickupEvent {
  PickupModel get currentPickup;
}

或投喜欢

_pushPickup((event as ButtonPressed).currentPickup);

如果您确定它将是 ButtonPressed。

你也可以这样做

if(event is ButtonPressed) {
  _pushPickup(event.currentPickup);
}