Flutter本地认证插件local_auth_darwin的使用

local_auth_darwin是Flutter中用于iOS和macOS平台实现本地认证功能的插件。它支持通过生物识别（如指纹、面部识别）或设备密码进行身份验证。

使用说明

该插件是被认可的，这意味着你可以直接使用local_auth包，而不需要在pubspec.yaml文件中显式添加local_auth_darwin依赖项。但是，如果你需要直接调用该插件提供的API，则需要将其添加到pubspec.yaml中。

示例Demo

下面是一个完整的示例代码，展示了如何在Flutter应用中使用local_auth_darwin进行本地认证：

// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// ignore_for_file: public_member_api_docs, avoid_print

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:local_auth/local_auth.dart'; // 导入local_auth包
import 'package:local_auth_platform_interface/local_auth_platform_interface.dart';

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

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  _SupportState _supportState = _SupportState.unknown;
  bool? _canCheckBiometrics;
  List<BiometricType>? _enrolledBiometrics;
  String _authorized = 'Not Authorized';
  bool _isAuthenticating = false;

  final LocalAuthentication _auth = LocalAuthentication();

  @override
  void initState() {
    super.initState();
    _checkDeviceSupport();
  }

  Future<void> _checkDeviceSupport() async {
    bool isSupported = await _auth.isDeviceSupported();
    setState(() {
      _supportState = isSupported ? _SupportState.supported : _SupportState.unsupported;
    });
  }

  Future<void> _checkBiometrics() async {
    try {
      bool deviceSupportsBiometrics = await _auth.canCheckBiometrics;
      setState(() {
        _canCheckBiometrics = deviceSupportsBiometrics;
      });
    } on PlatformException catch (e) {
      print(e);
    }
  }

  Future<void> _getEnrolledBiometrics() async {
    try {
      List<BiometricType> enrolledBiometrics = await _auth.getAvailableBiometrics();
      setState(() {
        _enrolledBiometrics = enrolledBiometrics;
      });
    } on PlatformException catch (e) {
      print(e);
    }
  }

  Future<void> _authenticate() async {
    try {
      setState(() {
        _isAuthenticating = true;
        _authorized = 'Authenticating';
      });
      bool authenticated = await _auth.authenticate(
        localizedReason: 'Let OS determine authentication method',
        options: const AuthenticationOptions(stickyAuth: true),
      );
      setState(() {
        _isAuthenticating = false;
        _authorized = authenticated ? 'Authorized' : 'Not Authorized';
      });
    } on PlatformException catch (e) {
      print(e);
      setState(() {
        _isAuthenticating = false;
        _authorized = 'Error - ${e.message}';
      });
    }
  }

  Future<void> _authenticateWithBiometrics() async {
    try {
      setState(() {
        _isAuthenticating = true;
        _authorized = 'Authenticating';
      });
      bool authenticated = await _auth.authenticate(
        localizedReason: 'Scan your fingerprint (or face or whatever) to authenticate',
        options: const AuthenticationOptions(stickyAuth: true, biometricOnly: true),
      );
      setState(() {
        _isAuthenticating = false;
        _authorized = authenticated ? 'Authorized' : 'Not Authorized';
      });
    } on PlatformException catch (e) {
      print(e);
      setState(() {
        _isAuthenticating = false;
        _authorized = 'Error - ${e.message}';
      });
    }
  }

  Future<void> _cancelAuthentication() async {
    await _auth.stopAuthentication();
    setState(() => _isAuthenticating = false);
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Plugin example app'),
        ),
        body: ListView(
          padding: const EdgeInsets.only(top: 30),
          children: <Widget>[
            Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                if (_supportState == _SupportState.unknown)
                  const CircularProgressIndicator()
                else if (_supportState == _SupportState.supported)
                  const Text('This device is supported')
                else
                  const Text('This device is not supported'),
                const Divider(height: 100),
                Text('Device supports biometrics: $_canCheckBiometrics\n'),
                ElevatedButton(
                  onPressed: _checkBiometrics,
                  child: const Text('Check biometrics'),
                ),
                const Divider(height: 100),
                Text('Enrolled biometrics: $_enrolledBiometrics\n'),
                ElevatedButton(
                  onPressed: _getEnrolledBiometrics,
                  child: const Text('Get enrolled biometrics'),
                ),
                const Divider(height: 100),
                Text('Current State: $_authorized\n'),
                if (_isAuthenticating)
                  ElevatedButton(
                    onPressed: _cancelAuthentication,
                    child: const Row(
                      mainAxisSize: MainAxisSize.min,
                      children: <Widget>[
                        Text('Cancel Authentication'),
                        Icon(Icons.cancel),
                      ],
                    ),
                  )
                else
                  Column(
                    children: <Widget>[
                      ElevatedButton(
                        onPressed: _authenticate,
                        child: const Row(
                          mainAxisSize: MainAxisSize.min,
                          children: <Widget>[
                            Text('Authenticate'),
                            Icon(Icons.perm_device_information),
                          ],
                        ),
                      ),
                      ElevatedButton(
                        onPressed: _authenticateWithBiometrics,
                        child: Row(
                          mainAxisSize: MainAxisSize.min,
                          children: <Widget>[
                            Text(_isAuthenticating ? 'Cancel' : 'Authenticate: biometrics only'),
                            const Icon(Icons.fingerprint),
                          ],
                        ),
                      ),
                    ],
                  ),
              ],
            ),
          ],
        ),
      ),
    );
  }
}

enum _SupportState {
  unknown,
  supported,
  unsupported,
}

关键点解释

• 导入依赖：确保在pubspec.yaml中添加了local_auth依赖。

  dependencies:
    flutter:
      sdk: flutter
    local_auth: ^2.0.0 # 确保版本号正确
  

• 检查设备支持：通过_auth.isDeviceSupported()方法检查当前设备是否支持本地认证。

• 生物识别支持：通过_auth.canCheckBiometrics属性判断设备是否支持生物识别，并通过_auth.getAvailableBiometrics()获取已注册的生物识别类型。

• 身份验证：通过_auth.authenticate()方法进行身份验证，可以选择使用所有可用的身份验证方式（包括密码），或者仅使用生物识别方式进行验证。

以上代码提供了一个完整的示例，展示了如何在Flutter应用中集成并使用local_auth插件进行本地认证。