Flutter桌面应用实战：Windows系统代理切换工具开发

前言

在日常开发工作中，我们经常需要在不同的网络环境下切换系统代理设置。传统的做法是通过Windows系统设置手动修改，操作繁琐且容易出错。本文将详细介绍如何使用Flutter开发一个Windows桌面应用，实现快速切换系统代理的功能。

项目概述

这个代理切换工具具有以下特点：

• 🖥️ Windows原生桌面应用
• 🔄 一键开启/关闭系统代理
• 💾 自动保存代理配置
• 🔍 实时检测当前代理状态
• ✅ 代理地址格式验证
• 🎨 Material Design 3 UI设计

技术栈选择

核心技术

• Flutter: 跨平台UI框架，支持桌面应用开发
• Dart: Flutter的编程语言
• Windows Registry: 通过注册表操作系统代理设置

主要依赖包

dependencies:flutter:sdk: fluttercupertino_icons: ^1.0.8win32: ^5.0.0  # Windows API调用ffi: ^2.1.0    # 外部函数接口window_size:   # 窗口大小控制git:url: https://github.com/google/flutter-desktop-embedding.gitpath: plugins/window_sizepath_provider: ^2.1.2  # 文件路径获取

完整代码实现

pubspec.yaml配置文件

name: proxy_switch
description: "Windows系统代理切换工具"
publish_to: 'none'version: 1.0.0+1environment:sdk: ^3.5.3dependencies:flutter:sdk: fluttercupertino_icons: ^1.0.8win32: ^5.0.0ffi: ^2.1.0window_size:git:url: https://github.com/google/flutter-desktop-embedding.gitpath: plugins/window_sizepath_provider: ^2.1.2dev_dependencies:flutter_test:sdk: flutterflutter_lints: ^4.0.0flutter:uses-material-design: true

主程序代码

import 'dart:io';
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:window_size/window_size.dart';void main() {WidgetsFlutterBinding.ensureInitialized();if (Platform.isWindows) {setWindowTitle('系统代理设置');setWindowMinSize(const Size(640, 480));setWindowMaxSize(const Size(960, 640));}runApp(const MyApp());
}class MyApp extends StatelessWidget {const MyApp({super.key});@overrideWidget build(BuildContext context) {return MaterialApp(title: '系统代理设置',theme: ThemeData(primarySwatch: Colors.blue,useMaterial3: true,fontFamily: 'Microsoft YaHei',textTheme: const TextTheme(displayLarge: TextStyle(fontFamily: 'Microsoft YaHei'),displayMedium: TextStyle(fontFamily: 'Microsoft YaHei'),displaySmall: TextStyle(fontFamily: 'Microsoft YaHei'),headlineLarge: TextStyle(fontFamily: 'Microsoft YaHei'),headlineMedium: TextStyle(fontFamily: 'Microsoft YaHei'),headlineSmall: TextStyle(fontFamily: 'Microsoft YaHei'),titleLarge: TextStyle(fontFamily: 'Microsoft YaHei'),titleMedium: TextStyle(fontFamily: 'Microsoft YaHei'),titleSmall: TextStyle(fontFamily: 'Microsoft YaHei'),bodyLarge: TextStyle(fontFamily: 'Microsoft YaHei'),bodyMedium: TextStyle(fontFamily: 'Microsoft YaHei'),bodySmall: TextStyle(fontFamily: 'Microsoft YaHei'),labelLarge: TextStyle(fontFamily: 'Microsoft YaHei'),labelMedium: TextStyle(fontFamily: 'Microsoft YaHei'),labelSmall: TextStyle(fontFamily: 'Microsoft YaHei'),),),home: const ProxySettingsPage(),);}
}class ProxySettingsPage extends StatefulWidget {const ProxySettingsPage({super.key});@overrideState<ProxySettingsPage> createState() => _ProxySettingsPageState();
}class _ProxySettingsPageState extends State<ProxySettingsPage> {final TextEditingController _proxyController = TextEditingController();bool _isProxyEnabled = false;String? _proxyError;late final File _configFile;@overridevoid initState() {super.initState();_initializeConfig().then((_) {_checkCurrentProxyStatus();if (_proxyController.text.isEmpty) {_loadConfig();}});}Future<void> _initializeConfig() async {final exePath = Platform.resolvedExecutable;final exeDir = Directory(File(exePath).parent.path);_configFile = File('${exeDir.path}\\proxy_config.json');if (!await _configFile.exists()) {await _configFile.create(recursive: true);await _saveConfig({'proxyAddress': ''});}}Future<void> _loadConfig() async {try {if (await _configFile.exists()) {final contents = await _configFile.readAsString();if (contents.isNotEmpty) {final config = json.decode(contents) as Map<String, dynamic>;setState(() {_proxyController.text = config['proxyAddress'] as String? ?? '';});}}} catch (e) {debugPrint('加载配置文件失败: $e');}}Future<void> _saveConfig(Map<String, dynamic> config) async {try {await _configFile.writeAsString(json.encode(config));} catch (e) {debugPrint('保存配置文件失败: $e');}}void _checkCurrentProxyStatus() {try {// 从注册表读取当前代理状态final result = Process.runSync('reg', ['query','HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings','/v','ProxyEnable']);if (result.exitCode == 0) {// 解析注册表输出final output = result.stdout.toString();final isEnabled = output.contains('0x1');// 如果代理已启用，读取代理地址if (isEnabled) {final proxyResult = Process.runSync('reg', ['query','HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings','/v','ProxyServer']);if (proxyResult.exitCode == 0) {final proxyOutput = proxyResult.stdout.toString();final proxyAddress = proxyOutput.split('REG_SZ')[1].trim();// 如果获取到有效的代理地址，更新状态并保存到配置文件if (proxyAddress.isNotEmpty) {setState(() {_proxyController.text = proxyAddress;_isProxyEnabled = true;});// 同时更新配置文件_saveConfig({'proxyAddress': proxyAddress});return;}}}setState(() {_isProxyEnabled = isEnabled;});}} catch (e) {debugPrint('检查代理状态时出错: $e');}}bool _validateProxyAddress(String address) {if (address.isEmpty) {setState(() {_proxyError = '代理地址不能为空';});return false;}// 检查格式：IP:端口 或 域名:端口final RegExp ipRegex = RegExp(r'^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?):\d{1,5}$');final RegExp domainRegex = RegExp(r'^([a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,}:\d{1,5}$');if (!ipRegex.hasMatch(address) && !domainRegex.hasMatch(address)) {setState(() {_proxyError = '代理地址格式无效，应为 IP:端口 或 域名:端口';});return false;}// 检查端口范围final port = int.parse(address.split(':').last);if (port < 1 || port > 65535) {setState(() {_proxyError = '端口号必须在 1-65535 之间';});return false;}setState(() {_proxyError = null;});return true;}void _toggleProxy(bool value) {if (value && !_validateProxyAddress(_proxyController.text)) {return;}setState(() {_isProxyEnabled = value;});if (value) {_setWindowsProxy(_proxyController.text);// 保存新的代理地址到配置文件_saveConfig({'proxyAddress': _proxyController.text});} else {_clearWindowsProxy();}}void _setWindowsProxy(String proxyAddress) {// 设置系统代理final cmdProcess = Process.runSync('reg', ['add','HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings','/v','ProxyEnable','/t','REG_DWORD','/d','1','/f']);if (cmdProcess.exitCode == 0) {Process.runSync('reg', ['add','HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings','/v','ProxyServer','/t','REG_SZ','/d',proxyAddress,'/f']);}}void _clearWindowsProxy() {Process.runSync('reg', ['add','HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings','/v','ProxyEnable','/t','REG_DWORD','/d','0','/f']);}@overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(backgroundColor: Theme.of(context).colorScheme.inversePrimary,title: const Text('系统代理设置'),centerTitle: true,actions: [IconButton(icon: const Icon(Icons.refresh),onPressed: () {_checkCurrentProxyStatus();ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('代理状态已刷新')),);},tooltip: '刷新代理状态',),],),body: Container(padding: const EdgeInsets.all(20.0),child: Column(crossAxisAlignment: CrossAxisAlignment.stretch,children: [Card(elevation: 2,child: Padding(padding: const EdgeInsets.all(16.0),child: Column(children: [Row(children: [Expanded(child: TextField(controller: _proxyController,decoration: InputDecoration(labelText: '代理地址',hintText: '例如: 127.0.0.1:7890',errorText: _proxyError,border: OutlineInputBorder(borderRadius: BorderRadius.circular(8),),prefixIcon: const Icon(Icons.computer),),onChanged: (value) {if (_proxyError != null) {setState(() {_proxyError = null;});}},),),const SizedBox(width: 8),IconButton(icon: const Icon(Icons.save),onPressed: () {if (_validateProxyAddress(_proxyController.text)) {_saveConfig({'proxyAddress': _proxyController.text});// 如果当前代理是启用状态，则更新系统代理地址if (_isProxyEnabled) {_setWindowsProxy(_proxyController.text);}ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('代理地址已保存')),);}},tooltip: '保存代理地址',),],),const SizedBox(height: 20),Container(padding: const EdgeInsets.symmetric(horizontal: 16,vertical: 8,),decoration: BoxDecoration(color: Theme.of(context).colorScheme.surfaceContainerHighest,borderRadius: BorderRadius.circular(8),),child: Row(mainAxisAlignment: MainAxisAlignment.spaceBetween,children: [Row(children: [Icon(_isProxyEnabled? Icons.cloud_done: Icons.cloud_off,color: _isProxyEnabled? Colors.green: Colors.grey,),const SizedBox(width: 8),const Text('启用系统代理',style: TextStyle(fontSize: 16,fontWeight: FontWeight.w500,),),],),Switch(value: _isProxyEnabled,onChanged: _toggleProxy,),],),),],),),),],),),);}@overridevoid dispose() {_proxyController.dispose();super.dispose();}
}

核心功能解析

1. 窗口配置与初始化

应用启动时，我们首先配置了窗口的基本属性：

void main() {WidgetsFlutterBinding.ensureInitialized();if (Platform.isWindows) {setWindowTitle('系统代理设置');setWindowMinSize(const Size(640, 480));setWindowMaxSize(const Size(960, 640));}runApp(const MyApp());
}

这里使用了window_size插件来控制窗口大小，确保应用在Windows平台上有合适的显示尺寸。

2. 配置文件管理

应用需要持久化保存用户的代理配置，我们将配置文件保存在可执行文件同目录下：

Future<void> _initializeConfig() async {final exePath = Platform.resolvedExecutable;final exeDir = Directory(File(exePath).parent.path);_configFile = File('${exeDir.path}\\proxy_config.json');if (!await _configFile.exists()) {await _configFile.create(recursive: true);await _saveConfig({'proxyAddress': ''});}
}

3. Windows注册表操作

这是整个应用的核心功能，通过操作Windows注册表来控制系统代理：

检查当前代理状态：

void _checkCurrentProxyStatus() {try {// 查询ProxyEnable注册表项final result = Process.runSync('reg', ['query','HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings','/v','ProxyEnable']);if (result.exitCode == 0) {final output = result.stdout.toString();final isEnabled = output.contains('0x1');// ... 后续处理}} catch (e) {debugPrint('检查代理状态时出错: $e');}
}

设置系统代理：

void _setWindowsProxy(String proxyAddress) {// 启用代理Process.runSync('reg', ['add','HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings','/v', 'ProxyEnable','/t', 'REG_DWORD','/d', '1','/f']);// 设置代理服务器地址Process.runSync('reg', ['add','HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings','/v', 'ProxyServer','/t', 'REG_SZ','/d', proxyAddress,'/f']);
}

4. 输入验证

为了确保用户输入的代理地址格式正确，我们实现了完善的验证机制：

bool _validateProxyAddress(String address) {if (address.isEmpty) {setState(() {_proxyError = '代理地址不能为空';});return false;}// IP地址格式验证final RegExp ipRegex = RegExp(r'^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?):\d{1,5}$');// 域名格式验证final RegExp domainRegex = RegExp(r'^([a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,}:\d{1,5}$');if (!ipRegex.hasMatch(address) && !domainRegex.hasMatch(address)) {setState(() {_proxyError = '代理地址格式无效，应为 IP:端口 或 域名:端口';});return false;}return true;
}

运行与部署

开发环境要求

• Flutter 3.5.3+
• Windows 10/11
• Visual Studio Code 或 Android Studio

编译打包

# 构建Windows桌面应用
flutter build windows# 生成的可执行文件位于
# build/windows/x64/runner/Release/proxy_switch.exe

使用说明

1. 在代理地址输入框中填入代理服务器地址（如：127.0.0.1:7890）
2. 点击保存按钮保存配置
3. 使用开关控制代理的启用/禁用
4. 点击刷新按钮检查当前系统代理状态

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