dart - Dart:使用Interface会产生错误: “isn' t的有效替代

Question

我创建了一个小界面:

import ...

abstract class IController {
  void navigateTo(BuildContext context, String routeName);
  Future<LocationData> get location;

  // registration process
  void registerGender(Gender gender);
  void registerBirthday(DateTime birthday);
  Future<bool> register(String email, String password);
}

然后我尝试实现这一点:

import ...

class Controller implements IController {
  static final Controller _instance = Controller._internal();
  final ServiceAuthenticate _serviceAuth = ServiceAuthenticate();
  final ServiceDatabase _serviceDb = ServiceDatabase();
  final ServiceGPS _serviceGPS = ServiceGPS();
  User _user;
  String _routeName;
  UserData _userData;

  Controller._internal() {
    this._routeName = ROUTE_WELCOME;
  }

  factory Controller() => _instance;

  void navigateTo(BuildContext context, String routeName) {
    this._routeName = routeName;
    Navigator.pushReplacementNamed(context, routeName);
  }

  Future<LocationData> get location async{
    this._userData.location = await this._serviceGPS.location;
    print(this._userData.location);
    return this._userData.location;
  }

  void registerGender(Gender gender){
    this._userData = UserData();
    this._userData.gender = gender;
  }

  void registerBirthday(DateTime birthday) {
    this._userData.birthday = birthday;
  }

  Future<bool> register(String email, String password) async {
    User user = await this._serviceAuth.registerWithEmailAndPassword(email, password);
    if(user == null){
      return false;
    }
    this._user = user;
    return true;
  }
}

但是该代码会产生以下错误:

error: 'Controller.navigateTo' ('void Function(BuildContext, String)') isn't a valid override of 'IController.navigateTo' ('void Function(dynamic, String)'). (invalid_override at [prototype] lib\controller\controller.dart:30)

似乎Dart认为 BuildContext中的 IController是 dynamic，但显然并非如此。
我怎样才能解决这个问题？我是Dart的新手，不知道该怎么办。
感谢帮助 :)

Answer 1

我真笨。
我的进口声明有误。
线

import 'package:prototype/Controller/IController.dart';

产生此错误，因为文件夹 controller以 小写字母开头。

正确的导入语句是

import 'package:prototype/controller/IController.dart';

但是无论我的愚蠢错误是什么，错误消息都非常有趣。