Windows/macOS/Linux全域加速延迟优化路线规划
iOS 后台下载 获取权限 在 `info.plist` 文件中添加 `Required background modes` 键，值设置为 `App downloads`。 启用后台下载任务 使用 `NSURLSession` 创建下载任务，并将其配置为在后台运行： ```swift let session = URLSession(configuration: .background(withIdentifier: "com.example.myapp.backgroundDownload")) let task = session.downloadTask(with: url) task.resume() ``` 监听任务进度 通过实现 `URLSessionDownloadDelegate` 协议来监听任务进度： ```swift extension ViewController: URLSessionDownloadDelegate { func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) { } func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) { // 下载进度更新 } } ``` Android 后台下载 配置 DownloadManager 创建 `DownloadManager` 对象并配置下载请求： ```j视频a DownloadManager downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE); DownloadManager.Request request = new DownloadManager.Request(uri); ``` 设置下载选项 设置 `setAllowedNetworkTypes` 以允许在后台下载，还可以设置其他选项，如通知和文件目的地： ```j视频a request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI | DownloadManager.Request.NETWORK_MOBILE); request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "myfile.zip"); ``` 启动下载 调用 `enqueue` 方法启动下载： ```j影音a long downloadId = downloadManager.enqueue(request); ``` 监听下载进度 通过 `BroadcastReceiver` 监听下载进度： ```j视频a BroadcastReceiver receiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { long downloadId = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1); if (downloadId == myDownloadId && status == DownloadManager.STATUS_SUCCESSFUL) { } } }; registerReceiver(receiver, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE)); ``` 注意： iOS：后台下载任务需要保持活跃，可以使用后台线程或 `NSOperationQueue`。 Android：设备在进入休眠或低电量模式时，可能会暂停后台下载。多终端平台持续交付测试全解析
