使用Alamofire的下載速率

Question

我正在使用此功能編寫帶有alamofire模塊的下載器應用程序，我想以MB / s為單位顯示當前下載速率，我真的不知道如何實現這一目標，請幫幫我。

---

  @IBAction func tapStartButton(_ sender: Any) {



    let fileUrl = self.getSaveFileUrl(fileName: Data[0] as String)
    let destination: DownloadRequest.DownloadFileDestination = { _, _ in
        return (fileUrl, [.removePreviousFile, .createIntermediateDirectories])
    }

    self.request = Alamofire.download(Data[0] as String , to:destination)

        .downloadProgress { (progress) in



        self.progressCircle.progress = progress.fractionCompleted




        cell.progressLabel.isHidden = false


        }

        .responseData { (data) in

            self.Data.removeFirst()
                self.startButton.isHidden = false
                self.pauseButton.isHidden = true

}

Answer 1

我認為Alamofire或其他任何圖書館都不提供下載速度。 開發人員必須自己計算。 您可以按照以下方式進行操作：

• 取一個保存先前下載字節的全局變量。
• 使用NSTimer以1秒的間隔來計算速度。

代碼示例：

  var prevDownloadedBytes: Int = 0
  var totalDownloadedBytes: Int = 0

  func calculateDownloadSpeed(){
   Timer.scheduleWith(timeInterval: 1.0, repeats: true){
     speed = totalDownloadedBytes - prevDownloadedBytes
     print("Speed is: \(speed) bps")
     prevDownloadedBytes = totalDownloadedBytes 
  }
}

  @IBAction func tapStartButton(_ sender: Any) {
    self.request = Alamofire.download(Data[0] as String , to:destination)
        .downloadProgress { (progress) in

        //Set Total Downloaded bytes here
        self.totalDownloadedBytes = progress.fileCompletedCount

        self.progressCircle.progress = progress.fractionCompleted
        cell.progressLabel.isHidden = false
        }
        .responseData { (data) in
            self.Data.removeFirst()
                self.startButton.isHidden = false
                self.pauseButton.isHidden = true
}