创建具有每个单元格进度视图的 UITableViewCell 自定义单元格时出现问题

问：

图像 1

向下和向上滚动后。进度条空白 ？？

图像 2

1. 每个单元格的自定义单元格，并通过 urlsession 下载。

   ## custom cell
   class chattingCustomCell: UITableViewCell {
   
   
   
   var downloadCustomTask:URLSessionDownloadTask!
    lazy var progressView : UIProgressView = {
   
    let progress = UIProgressView.init()
    progress.tintColor = .red
    return progress
    }()
   
   
   
    lazy var lbProgressView : UILabel = {
   
    let lb = UILabel.init()
    lb.textAlignment = .center
    return lb
     }()
   
    func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) {
    {
            DispatchQueue.main.async{
   
                if totalBytesExpectedToWrite > 0 {
                    let progress = Float(totalBytesWritten) / Float(totalBytesExpectedToWrite)
   
                    self.progressView.progress = progress
                    self.lbProgressView.text = "\(Float(totalBytesWritten)) / \(Float(totalBytesExpectedToWrite))"
   
                    //            DispatchQueue.main.async {
   
                    self.appDelegate.function.loglog(methodDesc: "\(NSStringFromClass(self.classForCoder))", str: "Video download progress : \(progress) -> \(Float(totalBytesWritten))/ \(Float(totalBytesExpectedToWrite))")
   
                    //                self.Progress.progress=progress
   
                    if(progress == 1)
                    {
   
                        self.appDelegate.function.loglog(methodDesc: "\(NSStringFromClass(self.classForCoder))", str: "Progress : done")
   
   
   
                    }
                    //            }
   
                    //            debugPrint("Progress \(downloadTask) \(progress)")
                }
            }
        }
   
   }
    .....
   
   
   
     override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)
   
   
    progressView = UIProgressView.init(frame: CGRect(x: (imageFrame.frame.size.width/2)-(150/2), y: (imageFrame.frame.size.height/2), width: 150, height: 10))
                        progressView.backgroundColor = UIColor.red
                        progressView.layer.zPosition = 10
                        progressView.progress = 0
                        self.imageFrame.addSubview(progressView)
                        lbProgressView = UILabel.init(frame: CGRect(x: (imageFrame.frame.size.width/2)-(150/2), y: (imageFrame.frame.size.height/2)+10, width: 150, height: 10))
                        lbProgressView.font = UIFont.systemFont(ofSize: 10)
                        lbProgressView.textAlignment = .center
                        self.imageFrame.addSubview(lbProgressView)
   
   
    }
   

2. 如果不滚动屏幕，它非常适合下载视频，每个单元格都显示进度状态。

3. 向下滚动和向上滚动屏幕时。进度视图是空白的，但 URLSession 仍在下载。

如何修复它。 感谢您的提前。