Question

我有一个应用程序，我需要从互联网上下载文件，当我下载文件它的工作正常，但我的问题是当我按下暂停按钮暂停下载一分钟或更长时间我从简历数据< / p>

以下我的代码：

@IBAction func startDownloading(_ sender: UIButton)
{     
    isDownload = true
    sessionConfig = URLSessionConfiguration.default
    let operationQueue = OperationQueue.main
    session = URLSession.init(configuration: sessionConfig, delegate: self, delegateQueue: operationQueue)
    let url = URL(string: "www.example.com")
    downloadTask = session.downloadTask(with: url!)
    downloadTask.resume()
}
@IBAction func pause(_ sender: UIButton) 
{
    if downloadTask != nil && isDownload 
    {
        self.downloadTask!.cancel(byProducingResumeData: { (resumeData) in
                        // here is the nil from the resume data
                    })
        isDownload = false
        downloadTask = nil
        pasueBtnOutlet.setTitle("Resume", for: .normal)
    }
    if !isDownload && downloadData != nil 
    {
        downloadTask = session.downloadTask(withResumeData: downloadData as Data)
        downloadTask.resume()
        isDownload = true
        downloadData = nil
        pasueBtnOutlet.setTitle("Pause", for: .normal)
    }                    
}

请帮帮我

感谢所有

Answer 1

您的代码似乎是正确的，您只需在关闭时使用downloadData初始化resumeData

制作downloadData

的属性

var downloadData:Data!

然后在您取消任务的暂停按钮操作中，将downloadData设置为resumeData

self.downloadTask!.cancel(byProducingResumeData: { (resumeData) in
        // here is the nil from the resume data

        // You have to set download data with resume data
        self.downloadData = resumeData
})

为了检查进度和完成情况，请实施这些URLSessionDownloadDelegate代理

func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) {
    let progress = Float(totalBytesWritten) / Float(totalBytesExpectedToWrite)
    print(Int(progress * 100))

}

func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) {
    print("Downloading done")
}

注意： - 尝试有效的可下载网址。例如 http://www.star.uclan.ac.uk/news_and_events/news/2010020901/sdo_resolution_comparison.png

其http，请务必在Info.plist中设置传输安全性

从URLSessionDownloadTask恢复数据始终为零

1 个答案: