如何根据用户角色创建视图以及如何创建login - Flutter

import 'package:flutter/material.dart';

enum UserRole {
  Admin,
  User,
}

class HomePage extends StatelessWidget {
  final UserRole userRole;

  HomePage({required this.userRole});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Home'),
      ),
      body: Center(
        child: userRole == UserRole.Admin
            ? AdminView()
            : userRole == UserRole.User
                ? UserView()
                : Container(),
      ),
    );
  }
}

class AdminView extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      child: Text('Admin View'),
    );
  }
}

class UserView extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      child: Text('User View'),
    );
  }
}

import 'package:flutter/material.dart';
import 'package:flutter_login/flutter_login.dart';

class LoginPage extends StatelessWidget {
  Duration get loginTime => Duration(milliseconds: 2250);

  Future<String?> _loginUser(LoginData data) {
    // 在这里执行登录逻辑，例如验证用户名和密码
    // 如果登录成功，返回null；如果登录失败，返回错误消息
    // 可以调用后端API进行验证

    return Future.delayed(loginTime).then((_) {
      if (data.password == 'password') {
        return null;
      } else {
        return '密码不正确';
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return FlutterLogin(
      title: 'Login',
      onLogin: _loginUser,
      onSubmitAnimationCompleted: () {
        // 登录成功后的回调函数
        // 可以在这里导航到主页或其他页面
      },
    );
  }
}