Flutter认证管理插件amplify_auth_cognito_dart的使用

Dart-only实现的Amplify认证插件。用于amplify_auth_cognito Flutter库的内部使用。

示例代码

Amplify Auth Cognito Dart 示例

示例应用和测试环境，用于amplify_auth_cognito_dart。

### 完整示例Demo

以下是一个完整的示例Demo，展示了如何在Flutter应用中使用`amplify_auth_cognito_dart`插件进行用户认证。

#### 1. 添加依赖

首先，在项目的`pubspec.yaml`文件中添加`amplify_auth_cognito_dart`依赖：

```yaml
dependencies:
  flutter:
    sdk: flutter
  amplify_auth_cognito_dart: ^<最新版本号>

2. 初始化Amplify

在应用启动时初始化Amplify库。通常在main.dart文件中的main()函数里进行初始化：

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

void main() {
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  [@override](/user/override)
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  final AmplifyAuthCognitoDart _auth = AmplifyAuthCognitoDart();

  [@override](/user/override)
  void initState() {
    super.initState();
    _configureAmplify();
  }

  Future<void> _configureAmplify() async {
    try {
      // 配置Amplify
      await _auth.configure();
      print("Amplify配置成功");
    } catch (e) {
      print("Amplify配置失败: $e");
    }
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Amplify Auth Cognito Dart 示例'),
        ),
        body: Center(
          child: Text('初始化完成，可以开始使用认证功能了！'),
        ),
      ),
    );
  }
}

3. 用户注册

接下来，我们可以实现用户注册功能。在应用中创建一个表单来收集用户的注册信息：

class RegisterScreen extends StatefulWidget {
  [@override](/user/override)
  _RegisterScreenState createState() => _RegisterScreenState();
}

class _RegisterScreenState extends State<RegisterScreen> {
  final TextEditingController _emailController = TextEditingController();
  final TextEditingController _passwordController = TextEditingController();

  Future<void> _registerUser() async {
    try {
      // 调用Amplify Auth API进行注册
      await _auth.signUp(
        username: _emailController.text,
        password: _passwordController.text,
      );
      print("用户注册成功");
    } catch (e) {
      print("用户注册失败: $e");
    }
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('用户注册'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          children: [
            TextField(
              controller: _emailController,
              decoration: InputDecoration(labelText: '邮箱'),
            ),
            TextField(
              controller: _passwordController,
              obscureText: true,
              decoration: InputDecoration(labelText: '密码'),
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: _registerUser,
              child: Text('注册'),
            ),
          ],
        ),
      ),
    );
  }
}

4. 用户登录

实现用户登录功能，同样创建一个表单来收集用户的登录信息：

class LoginScreen extends StatefulWidget {
  [@override](/user/override)
  _LoginScreenState createState() => _LoginScreenState();
}

class _LoginScreenState extends State<LoginScreen> {
  final TextEditingController _emailController = TextEditingController();
  final TextEditingController _passwordController = TextEditingController();

  Future<void> _loginUser() async {
    try {
      // 调用Amplify Auth API进行登录
      await _auth.signIn(
        username: _emailController.text,
        password: _passwordController.text,
      );
      print("用户登录成功");
    } catch (e) {
      print("用户登录失败: $e");
    }
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('用户登录'),
      ),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          children: [
            TextField(
              controller: _emailController,
              decoration: InputDecoration(labelText: '邮箱'),
            ),
            TextField(
              controller: _passwordController,
              obscureText: true,
              decoration: InputDecoration(labelText: '密码'),
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: _loginUser,
              child: Text('登录'),
            ),
          ],
        ),
      ),
    );
  }
}

5. 切换页面

最后，可以在主页面中添加按钮来切换到注册和登录页面：

class HomeScreen extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('主页'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            ElevatedButton(
              onPressed: () {
                Navigator.push(
                  context,
                  MaterialPageRoute(builder: (context) => RegisterScreen()),
                );
              },
              child: Text('注册'),
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: () {
                Navigator.push(
                  context,
                  MaterialPageRoute(builder: (context) => LoginScreen()),
                );
              },
              child: Text('登录'),
            ),
          ],
        ),
      ),
    );
  }
}