小编Ank*_*ati的帖子

我想实现下载功能，可以用百分比显示下载任务的完成状态。我能够做到这一点，但问题是当应用程序移至后台并返回前台时，didWriteData未在iOS12. 谁能帮帮我吗？这是我的代码

protocol DownloadDelagate {
    func downloadingProgress(value:Float)
    func downloadCompleted(identifier: Int,url: URL)
}

class DownloadManager : NSObject, URLSessionDelegate, URLSessionDownloadDelegate {

    static var shared = DownloadManager()
    var delegate: DownloadDelagate?
    var backgroundSessionCompletionHandler: (() -> Void)?

    var session : URLSession {
        get {

            let config = URLSessionConfiguration.background(withIdentifier: "\(Bundle.main.bundleIdentifier!).background")
            config.isDiscretionary = true
            config.sessionSendsLaunchEvents = true
            return URLSession(configuration: config, delegate: self, delegateQueue: OperationQueue())
        }
    }

    private override init() {
    }

    func urlSessionDidFinishEvents(forBackgroundURLSession session: URLSession) {
        DispatchQueue.main.async {
            if let completionHandler = self.backgroundSessionCompletionHandler …