颤振集团；预期 1 个位置参数，但找到 0 个

Question

颤振版本：2.1.0

Flutter Bloc 版本：^7.0.1

飞镖：2.13.0

出现此错误：应有 1 个位置参数，但找到了 0 个。尝试添加缺少的 arguments.dart(not_enough_positional_arguments)。

有什么不对的地方

我的侧边栏布局出错的地方：

 body: BlocProvider<NavigationBloc>(
        create: (context) => NavigationBloc(),
        child: Stack(
          children: [
            BlocBuilder<NavigationBloc, NavigationStates>(
                builder: (context, NavigationState) {
              return NavigationState as Widget;
            }),
            SideBar(),
          ],
        ),
      ),

我的 Bloc 导航文件：

import '/Pages/DeviceLocation/DeviceLocation.dart';

import '/Pages/Devices/DeviceLanding.dart';

import '../../LandingScreen/components/body.dart';
import '../../SensorScreen/charts/GasChart.dart';
import '../../SensorScreen/charts/HumChart.dart';
import '../../SensorScreen/charts/MoisChart.dart';
import '../../SensorScreen/charts/NurChart.dart';
import '../../SensorScreen/charts/PhChart.dart';
import '../../SensorScreen/charts/TemChart.dart';
import '../../SensorScreen/charts/chartComponents/NurCard.dart';
import 'package:bloc/bloc.dart';

enum NavigationEvents {
  // DashboardClickEvent,
  LandingScreenBodyClickEvent,
  TemChartClickEvent,
  HumChartClickEvent,
  MoisChartClickEvent,
  PhChartClickEvent,
  NurChartClickEvent,
  GasChartClickEvent,
  DevicesClickEvent,
  DevicesLocationClickEvent,
  AccountClickEvent,
  SettingsClickEvent
}

abstract class NavigationStates {}

class NavigationBloc extends Bloc<NavigationEvents, NavigationStates> {
  NavigationBloc(NavigationStates initialState) : super(initialState);

  @override
  NavigationStates get initialState => LandingScreenBody();

  @override
  Stream<NavigationStates> mapEventToState(NavigationEvents event) async* {
    switch (event) {
      case NavigationEvents.LandingScreenBodyClickEvent:
        yield LandingScreenBody();
        break;
      case NavigationEvents.TemChartClickEvent:
        yield TemChart();
        break;
      case NavigationEvents.HumChartClickEvent:
        yield HumChart();
        break;
      case NavigationEvents.MoisChartClickEvent:
        yield MoisChart();
        break;
      case NavigationEvents.PhChartClickEvent:
        yield PhChart();
        break;
      case NavigationEvents.NurChartClickEvent:
        yield NurChart();
        break;
      case NavigationEvents.GasChartClickEvent:
        yield GasChart();
        break;
      case NavigationEvents.DevicesClickEvent:
        yield DeviceLanding();
        break;
      case NavigationEvents.DevicesLocationClickEvent:
        yield DevicesLocation();
        break;
    }
  }
}

我在做什么？

Answer 1

您不必将状态传递给 bloc 构造函数，这应该可以工作

NavigationBloc() : super(LandingScreenBody());

在 flutter_bloc 7.0.0 中，不再有 initialState getter，所以你也必须删除它