Flutter应用自动更新系统：生产环境的挑战与解决方案

技术分享 5个月前 (09-21) 0 999+

Flutter应用自动更新系统：生产环境的挑战与解决方案

本文基于BeeCount(蜜蜂记账)项目的实际开发经验，深入探讨Android应用自动更新的完整实现，包括GitHub Releases集成、APK安装、R8混淆问题处理等核心技术难点。

项目背景

BeeCount(蜜蜂记账)是一款开源、简洁、无广告的个人记账应用。所有财务数据完全由用户掌控，支持本地存储和可选的云端同步，确保数据绝对安全。

引言

在移动应用开发中，自动更新功能是提升用户体验的重要环节。对于独立开发者而言，如何在没有应用商店分发渠道的情况下，构建一套可靠的应用更新机制，是一个充满挑战的技术问题。BeeCount通过GitHub Releases + 自动更新的方式，为用户提供了便捷的版本升级体验，但在实践中遇到了诸多技术难点，特别是生产环境下的R8代码混淆问题。

更新系统架构

整体架构设计

┌─────────────────┐    ┌──────────────────┐    ┌─────────────────┐ │   Flutter App   │    │   GitHub API     │    │   APK Storage   │ │   (Update UI)   │◄──►│   (Releases)     │◄──►│   (Assets)      │ │                 │    │                  │    │                 │ └─────────────────┘    └──────────────────┘    └─────────────────┘          │                       │                       │          └───── 版本检查 ─────────┼───── APK下载 ────────┘                                 │                     ┌──────────────────┐                     │   FileProvider   │                     │   (APK安装)      │                     └──────────────────┘

核心设计原则

版本检查智能化：自动对比本地与远程版本
下载体验优化：带进度条的后台下载
缓存机制：避免重复下载相同版本
安装流程简化：一键式更新体验
错误处理完善：网络异常、权限问题等场景处理
生产环境适配：R8混淆兼容性处理

更新服务核心实现

服务接口定义

abstract class UpdateService {   /// 检查更新   static Future<UpdateResult> checkUpdate();    /// 下载并安装更新   static Future<UpdateResult> downloadAndInstallUpdate(     BuildContext context,     String downloadUrl, {     Function(double progress, String status)? onProgress,   });    /// 显示更新对话框   static Future<void> showUpdateDialog(     BuildContext context, {     required bool isForced,     VoidCallback? onLaterPressed,     Function(double progress, String status)? onProgress,   });    /// 静默检查更新   static Future<void> silentCheckForUpdates(BuildContext context); }

版本检查实现

class UpdateService {   static final Dio _dio = Dio();   static const String _cachedApkPathKey = 'cached_apk_path';   static const String _cachedApkVersionKey = 'cached_apk_version';    /// 生成随机User-Agent，避免被GitHub限制   static String _generateRandomUserAgent() {     final userAgents = [       'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36',       'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36',       'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36',       // ... 更多User-Agent     ];      final random = (DateTime.now().millisecondsSinceEpoch % userAgents.length);     return userAgents[random];   }    /// 检查更新信息   static Future<UpdateResult> checkUpdate() async {     try {       // 获取当前版本信息       final currentInfo = await _getAppInfo();       final currentVersion = _normalizeVersion(currentInfo.version);        logI('UpdateService', '当前版本: $currentVersion');        // 检查缓存的APK       final cachedResult = await _checkCachedApk(currentVersion);       if (cachedResult != null) {         return cachedResult;       }        // 配置Dio超时和重试机制       _dio.options.connectTimeout = const Duration(seconds: 30);       _dio.options.receiveTimeout = const Duration(minutes: 2);       _dio.options.sendTimeout = const Duration(minutes: 2);        // 获取最新release信息 - 添加重试机制       Response? resp;       int attempts = 0;       const maxAttempts = 3;        while (attempts < maxAttempts) {         attempts++;         try {           logI('UpdateService', '尝试第$attempts次请求GitHub API...');           resp = await _dio.get(             'https://api.github.com/repos/TNT-Likely/BeeCount/releases/latest',             options: Options(               headers: {                 'Accept': 'application/vnd.github+json',                 'User-Agent': _generateRandomUserAgent(),               },             ),           );            if (resp.statusCode == 200) {             logI('UpdateService', 'GitHub API请求成功');             break;           } else {             logW('UpdateService', '第$attempts次请求返回错误状态码: ${resp.statusCode}');             if (attempts == maxAttempts) break;             await Future.delayed(const Duration(seconds: 1));           }         } catch (e) {           logE('UpdateService', '第$attempts次请求失败', e);           if (attempts == maxAttempts) rethrow;           await Future.delayed(Duration(seconds: 1 << attempts)); // 指数退避         }       }        if (resp?.statusCode != 200) {         return UpdateResult(           hasUpdate: false,           message: '检查更新失败: HTTP ${resp?.statusCode}',         );       }        final releaseData = resp!.data;       final latestVersion = _normalizeVersion(releaseData['tag_name']);       final releaseNotes = releaseData['body'] ?? '';       final publishedAt = DateTime.parse(releaseData['published_at']);        logI('UpdateService', '最新版本: $latestVersion');        // 版本比较       if (_compareVersions(latestVersion, currentVersion) <= 0) {         logI('UpdateService', '已是最新版本');         return UpdateResult(hasUpdate: false, message: '已是最新版本');       }        // 查找APK下载链接       final assets = releaseData['assets'] as List;       String? downloadUrl;        for (final asset in assets) {         final name = asset['name'] as String;         if (name.toLowerCase().endsWith('.apk') &&             (name.contains('prod') || name.contains('release'))) {           downloadUrl = asset['browser_download_url'];           break;         }       }        if (downloadUrl == null) {         return UpdateResult(           hasUpdate: false,           message: '未找到APK下载链接',         );       }        logI('UpdateService', '发现新版本: $latestVersion');       return UpdateResult(         hasUpdate: true,         version: latestVersion,         downloadUrl: downloadUrl,         releaseNotes: releaseNotes,         publishedAt: publishedAt,         message: '发现新版本 $latestVersion',       );      } catch (e) {       logE('UpdateService', '检查更新异常', e);       return UpdateResult(         hasUpdate: false,         message: '检查更新失败: ${e.toString()}',       );     }   }    /// 检查缓存的APK   static Future<UpdateResult?> _checkCachedApk(String currentVersion) async {     try {       final prefs = await SharedPreferences.getInstance();       final cachedApkPath = prefs.getString(_cachedApkPathKey);       final cachedApkVersion = prefs.getString(_cachedApkVersionKey);        if (cachedApkPath != null && cachedApkVersion != null) {         final file = File(cachedApkPath);         if (await file.exists()) {           // 检查缓存版本是否比当前版本新           if (_compareVersions(cachedApkVersion, currentVersion) > 0) {             logI('UpdateService', '找到缓存的新版本APK: $cachedApkVersion');             return UpdateResult.cachedUpdate(               version: cachedApkVersion,               filePath: cachedApkPath,             );           }         } else {           // 清理无效的缓存记录           await prefs.remove(_cachedApkPathKey);           await prefs.remove(_cachedApkVersionKey);         }       }     } catch (e) {       logE('UpdateService', '检查缓存APK失败', e);     }     return null;   }    /// 版本号比较   static int _compareVersions(String v1, String v2) {     final parts1 = v1.split('.').map(int.parse).toList();     final parts2 = v2.split('.').map(int.parse).toList();      final maxLength = math.max(parts1.length, parts2.length);      // 补齐长度     while (parts1.length < maxLength) parts1.add(0);     while (parts2.length < maxLength) parts2.add(0);      for (int i = 0; i < maxLength; i++) {       if (parts1[i] > parts2[i]) return 1;       if (parts1[i] < parts2[i]) return -1;     }      return 0;   }    /// 规范化版本号   static String _normalizeVersion(String version) {     // 移除v前缀和构建后缀     String normalized = version.replaceAll(RegExp(r'^v'), '');     normalized = normalized.replaceAll(RegExp(r'-.*$'), '');     return normalized;   } }

APK下载实现

/// 下载APK文件 static Future<UpdateResult> _downloadApk(   BuildContext context,   String url,   String fileName, {   Function(double progress, String status)? onProgress, }) async {   try {     // 获取下载目录     Directory? downloadDir;     if (Platform.isAndroid) {       downloadDir = await getExternalStorageDirectory();     }     downloadDir ??= await getApplicationDocumentsDirectory();      final filePath = '${downloadDir.path}/BeeCount_$fileName.apk';     logI('UpdateService', '下载路径: $filePath');      // 删除已存在的文件     final file = File(filePath);     if (await file.exists()) {       logI('UpdateService', '删除已存在的同版本文件: $filePath');       await file.delete();     }      // 显示下载进度对话框和通知     double progress = 0.0;     bool cancelled = false;     late StateSetter dialogSetState;      final cancelToken = CancelToken();      // 显示初始通知     await _showProgressNotification(0, indeterminate: false);      if (context.mounted) {       showDialog(         context: context,         barrierDismissible: false,         builder: (context) => StatefulBuilder(           builder: (context, setState) {             dialogSetState = setState;             return AlertDialog(               title: const Text('下载更新'),               content: Column(                 mainAxisSize: MainAxisSize.min,                 children: [                   Text('下载中: ${(progress * 100).toStringAsFixed(1)}%'),                   const SizedBox(height: 16),                   LinearProgressIndicator(value: progress),                   const SizedBox(height: 16),                   Row(                     mainAxisAlignment: MainAxisAlignment.spaceEvenly,                     children: [                       TextButton(                         onPressed: () {                           cancelled = true;                           cancelToken.cancel('用户取消下载');                           Navigator.of(context).pop();                         },                         child: const Text('取消'),                       ),                       TextButton(                         onPressed: () {                           Navigator.of(context).pop();                         },                         child: const Text('后台下载'),                       ),                     ],                   ),                 ],               ),             );           },         ),       );     }      // 开始下载     await _dio.download(       url,       filePath,       options: Options(         headers: {           'User-Agent': _generateRandomUserAgent(),         },       ),       onReceiveProgress: (received, total) {         if (total > 0 && !cancelled) {           final newProgress = received / total;           progress = newProgress;           final progressPercent = (progress * 100).round();            // 调用外部进度回调           onProgress?.call(newProgress, '下载中: $progressPercent%');            // 更新UI进度           try {             if (context.mounted) {               dialogSetState(() {});             }           } catch (e) {             // 对话框已关闭，忽略错误           }            // 更新通知进度           _showProgressNotification(progressPercent, indeterminate: false)               .catchError((e) {             logE('UpdateService', '更新通知进度失败', e);           });         }       },       cancelToken: cancelToken,     );      if (cancelled) {       logI('UpdateService', '用户取消下载');       await _cancelDownloadNotification();       onProgress?.call(0.0, '');       return UpdateResult.userCancelled();     }      // 下载完成，关闭进度对话框     logI('UpdateService', '下载完成，关闭下载进度对话框');     if (context.mounted) {       try {         if (Navigator.of(context).canPop()) {           Navigator.of(context).pop();           logI('UpdateService', '下载进度对话框已关闭');         }       } catch (e) {         logW('UpdateService', '关闭下载对话框失败: $e');       }     }      // 等待对话框完全关闭     await Future.delayed(const Duration(milliseconds: 800));      logI('UpdateService', '下载完成: $filePath');     onProgress?.call(0.9, '下载完成');      // 保存APK路径和版本信息到缓存     await _saveApkPath(filePath, fileName);      await _showDownloadCompleteNotification(filePath);     onProgress?.call(1.0, '完成');     return UpdateResult.downloadSuccess(filePath);    } catch (e) {     // 检查是否是用户取消导致的异常     if (e is DioException && e.type == DioExceptionType.cancel) {       logI('UpdateService', '用户取消下载（通过异常捕获）');       await _cancelDownloadNotification();       onProgress?.call(0.0, '');       return UpdateResult.userCancelled();     }      // 真正的下载错误     logE('UpdateService', '下载失败', e);      // 安全关闭下载对话框     if (context.mounted) {       try {         if (Navigator.of(context).canPop()) {           Navigator.of(context).pop();           await Future.delayed(const Duration(milliseconds: 300));         }       } catch (navError) {         logE('UpdateService', '关闭下载对话框失败', navError);       }     }      await _cancelDownloadNotification();     onProgress?.call(0.0, '');     return UpdateResult.error('下载失败: $e');   } }  /// 保存APK路径到缓存 static Future<void> _saveApkPath(String filePath, String version) async {   try {     final prefs = await SharedPreferences.getInstance();     await prefs.setString(_cachedApkPathKey, filePath);     await prefs.setString(_cachedApkVersionKey, version);     logI('UpdateService', '已保存APK缓存信息: $version -> $filePath');   } catch (e) {     logE('UpdateService', '保存APK缓存信息失败', e);   } }

APK安装核心问题

R8代码混淆导致的崩溃

在生产环境构建中，我们遇到了一个严重问题：APK安装功能在开发环境正常，但在生产环境100%崩溃。通过详细的日志分析，发现了问题的根本原因：

// 崩溃日志 java.lang.IncompatibleClassChangeError: Class android.content.res.XmlBlock$Parser does not implement interface 'g3.a'     at androidx.core.content.FileProvider.getUriForFile(FileProvider.java:400)

问题分析：

R8混淆器将android.content.res.XmlBlock$Parser接口重命名为g3.a
FileProvider读取file_paths.xml时无法找到正确的XML解析器接口
导致FileProvider.getUriForFile()调用失败

Proguard规则修复

# 保护XML解析器相关类不被混淆（关键修复） -keep class android.content.res.XmlBlock { *; } -keep class android.content.res.XmlBlock$Parser { *; } -keep interface android.content.res.XmlResourceParser { *; } -keep interface org.xmlpull.v1.XmlPullParser { *; }  # 保护XML解析实现类 -keep class org.xmlpull.v1.** { *; } -dontwarn org.xmlpull.v1.**  # 保护Android系统XML接口不被混淆 -keep interface android.content.res.** { *; } -keep class android.content.res.** { *; }  # 保护FileProvider相关类 -keep class androidx.core.content.FileProvider { *; } -keep class androidx.core.content.FileProvider$** { *; } -keepclassmembers class androidx.core.content.FileProvider {     public *;     private *; }  # 保护FileProvider路径配置 -keepattributes *Annotation* -keep class * extends androidx.core.content.FileProvider -keepclassmembers class ** {     @androidx.core.content.FileProvider$* <fields>; }

Android原生安装实现

class MainActivity : FlutterActivity() {     private val INSTALL_CHANNEL = "com.example.beecount/install"      override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {         super.configureFlutterEngine(flutterEngine)          // APK安装的MethodChannel         MethodChannel(flutterEngine.dartExecutor.binaryMessenger, INSTALL_CHANNEL)             .setMethodCallHandler { call, result ->                 when (call.method) {                     "installApk" -> {                         val filePath = call.argument<String>("filePath")                         if (filePath != null) {                             val success = installApkWithIntent(filePath)                             result.success(success)                         } else {                             result.error("INVALID_ARGUMENT", "文件路径不能为空", null)                         }                     }                     else -> result.notImplemented()                 }             }     }      private fun installApkWithIntent(filePath: String): Boolean {         return try {             android.util.Log.d("MainActivity", "UPDATE_CRASH: 开始原生Intent安装APK: $filePath")              val sourceFile = File(filePath)             if (!sourceFile.exists()) {                 android.util.Log.e("MainActivity", "UPDATE_CRASH: APK文件不存在: $filePath")                 return false             }              // 直接在缓存根目录创建APK，避免子目录配置问题             val cachedApk = File(cacheDir, "install.apk")             sourceFile.copyTo(cachedApk, overwrite = true)             android.util.Log.d("MainActivity", "UPDATE_CRASH: APK已复制到: ${cachedApk.absolutePath}")              val intent = Intent(Intent.ACTION_VIEW)              try {                 val uri = FileProvider.getUriForFile(                     this,                     "$packageName.fileprovider",                     cachedApk                 )                 android.util.Log.d("MainActivity", "UPDATE_CRASH: ✅ FileProvider URI创建成功: $uri")                  intent.setDataAndType(uri, "application/vnd.android.package-archive")                 intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)              } catch (e: IllegalArgumentException) {                 android.util.Log.e("MainActivity", "UPDATE_CRASH: ❌ FileProvider路径配置错误", e)                 return false             } catch (e: Exception) {                 android.util.Log.e("MainActivity", "UPDATE_CRASH: ❌ FileProvider创建URI失败", e)                 return false             }              intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)              // 检查是否有应用可以处理该Intent             if (intent.resolveActivity(packageManager) != null) {                 android.util.Log.d("MainActivity", "UPDATE_CRASH: 找到可处理APK安装的应用")                 startActivity(intent)                 android.util.Log.d("MainActivity", "UPDATE_CRASH: ✅ APK安装Intent启动成功")                 return true             } else {                 android.util.Log.e("MainActivity", "UPDATE_CRASH: ❌ 没有应用可以处理APK安装")                 return false             }          } catch (e: Exception) {             android.util.Log.e("MainActivity", "UPDATE_CRASH: ❌ 原生Intent安装失败: $e")             return false         }     } }

FileProvider配置

<!-- android/app/src/main/res/xml/file_paths.xml --> <?xml version="1.0" encoding="utf-8"?> <paths xmlns:android="http://schemas.android.com/apk/res/android">     <!-- 允许访问cache/apk目录 -->     <cache-path name="apk_cache" path="apk/" />     <!-- 允许访问全部缓存目录作为备用 -->     <cache-path name="all_cache" path="." />     <!-- External app-specific files directory -->     <external-files-path name="external_app_files" path="." /> </paths>

<!-- android/app/src/main/AndroidManifest.xml --> <!-- FileProvider for sharing APK files on Android 7.0+ --> <provider     android:name="androidx.core.content.FileProvider"     android:authorities="${applicationId}.fileprovider"     android:exported="false"     android:grantUriPermissions="true">     <meta-data         android:name="android.support.FILE_PROVIDER_PATHS"         android:resource="@xml/file_paths" /> </provider>

Flutter更新服务集成

安装APK实现

/// 安装APK static Future<bool> _installApk(String filePath) async {   try {     logI('UpdateService', 'UPDATE_CRASH: === 开始APK安装流程 ===');     logI('UpdateService', 'UPDATE_CRASH: 文件路径: $filePath');      // 检查文件是否存在     final file = File(filePath);     final fileExists = await file.exists();     logI('UpdateService', 'UPDATE_CRASH: APK文件存在: $fileExists');      if (!fileExists) {       logE('UpdateService', 'UPDATE_CRASH: APK文件不存在');       return false;     }      final fileSize = await file.length();     logI('UpdateService', 'UPDATE_CRASH: APK文件大小: $fileSize 字节');      // 检查权限状态     final installPermission = await Permission.requestInstallPackages.status;     logI('UpdateService', 'UPDATE_CRASH: 安装权限状态: $installPermission');      // 在生产环境中使用更安全的调用方式     bool success = false;     if (const bool.fromEnvironment('dart.vm.product')) {       logI('UpdateService', 'UPDATE_CRASH: 生产环境，使用原生Intent方式安装');       try {         success = await _installApkWithIntent(filePath);       } catch (intentException) {         logE('UpdateService', 'UPDATE_CRASH: Intent安装失败，尝试OpenFilex备用方案', intentException);         try {           final result = await OpenFilex.open(filePath);           logI('UpdateService', 'UPDATE_CRASH: === OpenFilex.open备用调用完成 ===');           success = result.type == ResultType.done;         } catch (openFileException) {           logE('UpdateService', 'UPDATE_CRASH: OpenFilex备用方案也失败', openFileException);           success = false;         }       }     } else {       // 开发环境使用原来的方式       final result = await OpenFilex.open(filePath);       logI('UpdateService', 'UPDATE_CRASH: === OpenFilex.open调用完成 ===');       logI('UpdateService', 'UPDATE_CRASH: 返回类型: ${result.type}');       logI('UpdateService', 'UPDATE_CRASH: 返回消息: ${result.message}');       success = result.type == ResultType.done;     }      logI('UpdateService', 'UPDATE_CRASH: 安装结果判定: $success');      if (success) {       logI('UpdateService', 'UPDATE_CRASH: ✅ APK安装程序启动成功');     } else {       logW('UpdateService', 'UPDATE_CRASH: ⚠️ APK安装程序启动失败');     }      return success;   } catch (e, stackTrace) {     logE('UpdateService', 'UPDATE_CRASH: ❌ 安装APK过程中发生异常', e);     logE('UpdateService', 'UPDATE_CRASH: 异常堆栈: $stackTrace');     return false;   } }  /// 使用原生Android Intent安装APK（生产环境专用） static Future<bool> _installApkWithIntent(String filePath) async {   try {     logI('UpdateService', 'UPDATE_CRASH: 开始使用Intent安装APK');      if (!Platform.isAndroid) {       logE('UpdateService', 'UPDATE_CRASH: 非Android平台，无法使用Intent安装');       return false;     }      // 使用MethodChannel调用原生Android代码     const platform = MethodChannel('com.example.beecount/install');      logI('UpdateService', 'UPDATE_CRASH: 调用原生安装方法，文件路径: $filePath');      final result = await platform.invokeMethod('installApk', {       'filePath': filePath,     });      logI('UpdateService', 'UPDATE_CRASH: 原生安装方法调用完成，结果: $result');      return result == true;   } catch (e, stackTrace) {     logE('UpdateService', 'UPDATE_CRASH: Intent安装异常', e);     logE('UpdateService', 'UPDATE_CRASH: Intent安装异常堆栈', stackTrace);     return false;   } }

缓存APK处理修复

在实际使用中发现的另一个问题：当用户选择安装缓存的APK时，系统返回了错误的成功状态。

问题原因：UpdateResult构造函数中success参数的默认值是false，但安装缓存APK时没有显式设置为true。

// 问题代码 return UpdateResult(   hasUpdate: true,   message: '正在安装缓存的APK',  // 缺少 success: true   filePath: cachedApkPath, );  // 修复后代码 return UpdateResult(   hasUpdate: true,   success: true,  // 明确设置成功状态   message: '正在安装缓存的APK',   filePath: cachedApkPath, );

用户界面设计

更新对话框

/// 显示更新对话框 static Future<void> showUpdateDialog(   BuildContext context, {   required bool isForced,   VoidCallback? onLaterPressed,   Function(double progress, String status)? onProgress, }) async {   final result = await checkUpdate();    if (!result.hasUpdate) {     if (context.mounted) {       ScaffoldMessenger.of(context).showSnackBar(         SnackBar(content: Text(result.message ?? '已是最新版本')),       );     }     return;   }    if (!context.mounted) return;    // 显示更新确认对话框   final shouldUpdate = await showDialog<bool>(     context: context,     barrierDismissible: !isForced,     builder: (context) => AlertDialog(       title: Row(         children: [           Icon(Icons.system_update, color: Theme.of(context).primaryColor),           const SizedBox(width: 12),           Text('发现新版本：${result.version}'),         ],       ),       content: SingleChildScrollView(         child: Column(           mainAxisSize: MainAxisSize.min,           crossAxisAlignment: CrossAxisAlignment.start,           children: [             if (result.releaseNotes?.isNotEmpty == true) ...[               const Text('更新内容：', style: TextStyle(fontWeight: FontWeight.bold)),               const SizedBox(height: 8),               Container(                 padding: const EdgeInsets.all(12),                 decoration: BoxDecoration(                   color: Colors.grey[100],                   borderRadius: BorderRadius.circular(8),                 ),                 child: Text(                   result.releaseNotes!,                   style: const TextStyle(fontSize: 14),                 ),               ),               const SizedBox(height: 16),             ],              if (result.publishedAt != null) ...[               Text(                 '发布时间: ${_formatPublishTime(result.publishedAt!)}',                 style: TextStyle(                   fontSize: 12,                   color: Colors.grey[600],                 ),               ),               const SizedBox(height: 8),             ],              Container(               padding: const EdgeInsets.all(12),               decoration: BoxDecoration(                 color: Colors.blue[50],                 borderRadius: BorderRadius.circular(8),                 border: Border.all(color: Colors.blue[200]!),               ),               child: Row(                 children: [                   Icon(Icons.info, color: Colors.blue[700], size: 20),                   const SizedBox(width: 8),                   Expanded(                     child: Text(                       '更新将下载APK文件并自动安装',                       style: TextStyle(                         fontSize: 13,                         color: Colors.blue[700],                       ),                     ),                   ),                 ],               ),             ),           ],         ),       ),       actions: [         if (!isForced) ...[           OutlinedButton(             style: OutlinedButton.styleFrom(               foregroundColor: Theme.of(context).primaryColor,             ),             onPressed: () {               Navigator.of(context).pop(false);               onLaterPressed?.call();             },             child: const Text('稍后更新'),           ),         ],         ElevatedButton(           onPressed: () => Navigator.of(context).pop(true),           child: const Text('立即更新'),         ),       ],     ),   );    if (shouldUpdate == true && context.mounted) {     // 开始下载和安装     await downloadAndInstallUpdate(       context,       result.downloadUrl!,       onProgress: onProgress,     );   } }  String _formatPublishTime(DateTime publishTime) {   final now = DateTime.now();   final difference = now.difference(publishTime);    if (difference.inDays > 0) {     return '${difference.inDays}天前';   } else if (difference.inHours > 0) {     return '${difference.inHours}小时前';   } else if (difference.inMinutes > 0) {     return '${difference.inMinutes}分钟前';   } else {     return '刚刚';   } }

下载进度通知

/// 显示下载进度通知 static Future<void> _showProgressNotification(   int progress, {   bool indeterminate = false, }) async {   try {     const androidDetails = AndroidNotificationDetails(       'download_channel',       '下载进度',       channelDescription: '显示应用更新下载进度',       importance: Importance.low,       priority: Priority.low,       showProgress: true,       maxProgress: 100,       progress: 0,       indeterminate: false,       ongoing: true,       autoCancel: false,     );      const notificationDetails = NotificationDetails(android: androidDetails);      await _notificationsPlugin.show(       _downloadNotificationId,       '蜜蜂记账更新',       indeterminate ? '准备下载...' : '下载进度: $progress%',       notificationDetails.copyWith(         android: androidDetails.copyWith(           progress: progress,           indeterminate: indeterminate,         ),       ),     );   } catch (e) {     logE('UpdateService', '显示进度通知失败', e);   } }  /// 显示下载完成通知 static Future<void> _showDownloadCompleteNotification(String filePath) async {   try {     const androidDetails = AndroidNotificationDetails(       'download_channel',       '下载完成',       channelDescription: '显示应用更新下载完成',       importance: Importance.high,       priority: Priority.high,       autoCancel: true,     );      const notificationDetails = NotificationDetails(android: androidDetails);      await _notificationsPlugin.show(       _downloadNotificationId,       '蜜蜂记账更新',       '下载完成，点击安装',       notificationDetails,     );   } catch (e) {     logE('UpdateService', '显示完成通知失败', e);   } }

错误处理和用户体验

网络异常处理

/// 网络重试机制 class NetworkOptimizer {   static const int maxRetries = 3;   static const Duration retryDelay = Duration(seconds: 2);    static Future<T> withRetry<T>(Future<T> Function() operation) async {     int attempts = 0;      while (attempts < maxRetries) {       try {         return await operation();       } catch (e) {         attempts++;          if (attempts >= maxRetries) {           rethrow;         }          // 指数退避         await Future.delayed(retryDelay * (1 << attempts));       }     }      throw Exception('Max retries exceeded');   }    static Future<bool> isNetworkAvailable() async {     try {       final result = await InternetAddress.lookup('github.com');       return result.isNotEmpty && result[0].rawAddress.isNotEmpty;     } catch (_) {       return false;     }   } }

权限处理

/// 检查和申请权限 static Future<bool> _checkAndRequestPermissions() async {   if (!Platform.isAndroid) return true;    logI('UpdateService', '开始检查权限...');    try {     // 检查安装权限     var installPermission = await Permission.requestInstallPackages.status;     logI('UpdateService', '安装权限状态: $installPermission');      if (installPermission.isDenied) {       logI('UpdateService', '请求安装权限...');       installPermission = await Permission.requestInstallPackages.request();       logI('UpdateService', '权限请求结果: $installPermission');     }      if (installPermission.isPermanentlyDenied) {       logW('UpdateService', '安装权限被永久拒绝，引导用户手动开启');       return false;     }      // 检查存储权限（Android 10以下需要）     if (Platform.isAndroid && await _needsStoragePermission()) {       var storagePermission = await Permission.storage.status;       logI('UpdateService', '存储权限状态: $storagePermission');        if (storagePermission.isDenied) {         storagePermission = await Permission.storage.request();         logI('UpdateService', '存储权限请求结果: $storagePermission');       }        if (!storagePermission.isGranted) {         logW('UpdateService', '存储权限未授予');         return false;       }     }      return installPermission.isGranted;   } catch (e) {     logE('UpdateService', '权限检查失败', e);     return false;   } }  static Future<bool> _needsStoragePermission() async {   final info = await DeviceInfoPlugin().androidInfo;   return info.version.sdkInt < 29; // Android 10以下需要存储权限 }

错误回退机制

/// 显示下载失败的错误弹窗，提供去GitHub的兜底选项 static Future<void> _showDownloadErrorWithFallback(   BuildContext context,   String errorMessage, ) async {   if (!context.mounted) return;    final result = await showDialog<bool>(     context: context,     builder: (context) => AlertDialog(       title: Row(         children: [           const Icon(Icons.error_outline, color: Colors.orange, size: 28),           const SizedBox(width: 12),           const Text('下载失败'),         ],       ),       content: Column(         mainAxisSize: MainAxisSize.min,         crossAxisAlignment: CrossAxisAlignment.start,         children: [           Text(             '下载更新文件失败：n$errorMessage',             style: const TextStyle(fontSize: 16),           ),           const SizedBox(height: 16),           Container(             padding: const EdgeInsets.all(12),             decoration: BoxDecoration(               color: Colors.blue[50],               borderRadius: BorderRadius.circular(8),               border: Border.all(color: Colors.blue[200]!),             ),             child: Row(               crossAxisAlignment: CrossAxisAlignment.start,               children: [                 Icon(Icons.lightbulb, color: Colors.blue[700], size: 20),                 const SizedBox(width: 8),                 Expanded(                   child: Text(                     '您可以手动前往GitHub Releases页面下载最新版本APK文件',                     style: TextStyle(                       fontSize: 13,                       color: Colors.blue[700],                     ),                   ),                 ),               ],             ),           ),         ],       ),       actions: [         TextButton(           onPressed: () => Navigator.of(context).pop(false),           child: const Text('取消'),         ),         ElevatedButton.icon(           onPressed: () => Navigator.of(context).pop(true),           icon: const Icon(Icons.open_in_new),           label: const Text('前往GitHub'),         ),       ],     ),   );    if (result == true && context.mounted) {     await _launchGitHubReleases(context);   } }  /// 打开GitHub Releases页面 static Future<void> _launchGitHubReleases(BuildContext context) async {   const url = 'https://github.com/TNT-Likely/BeeCount/releases';    try {     final uri = Uri.parse(url);     if (await canLaunchUrl(uri)) {       await launchUrl(uri, mode: LaunchMode.externalApplication);     } else {       throw Exception('无法打开链接');     }   } catch (e) {     if (context.mounted) {       ScaffoldMessenger.of(context).showSnackBar(         SnackBar(           content: Text('打开链接失败: $e'),           action: SnackBarAction(             label: '复制链接',             onPressed: () {               Clipboard.setData(const ClipboardData(text: url));             },           ),         ),       );     }   } }

性能优化和最佳实践

版本检查优化

/// 静默检查更新（应用启动时调用） static Future<void> silentCheckForUpdates(BuildContext context) async {   try {     // 避免频繁检查，每天最多检查一次     final prefs = await SharedPreferences.getInstance();     final lastCheck = prefs.getString('last_update_check');     final now = DateTime.now();      if (lastCheck != null) {       final lastCheckTime = DateTime.parse(lastCheck);       if (now.difference(lastCheckTime).inHours < 24) {         logI('UpdateService', '距离上次检查不足24小时，跳过静默检查');         return;       }     }      logI('UpdateService', '开始静默检查更新');     final result = await checkUpdate();      // 记录检查时间     await prefs.setString('last_update_check', now.toIso8601String());      if (result.hasUpdate && context.mounted) {       // 显示轻量级的更新提示       ScaffoldMessenger.of(context).showSnackBar(         SnackBar(           content: Text('发现新版本 ${result.version}'),           action: SnackBarAction(             label: '立即更新',             onPressed: () {               showUpdateDialog(context, isForced: false);             },           ),           duration: const Duration(seconds: 8),         ),       );     }   } catch (e) {     logE('UpdateService', '静默检查更新失败', e);   } }

缓存管理

/// 清理旧的APK文件 static Future<void> _cleanupOldApkFiles() async {   try {     final downloadDir = await getExternalStorageDirectory() ??                        await getApplicationDocumentsDirectory();      final apkFiles = downloadDir         .listSync()         .where((file) => file.path.toLowerCase().endsWith('.apk'))         .cast<File>();      final currentVersion = await _getCurrentVersion();      for (final file in apkFiles) {       try {         // 保留当前版本和更新版本的APK，删除其他版本         if (!file.path.contains(currentVersion) &&             !file.path.contains('BeeCount_')) {           await file.delete();           logI('UpdateService', '清理旧APK文件: ${file.path}');         }       } catch (e) {         logW('UpdateService', '清理APK文件失败: ${file.path}', e);       }     }   } catch (e) {     logE('UpdateService', '清理APK文件异常', e);   } }