如果图库ios

Question

在此代码中，我们使用“alamofire”下载图像，但在那里我想要替换图像，所以请帮助我。当我得到响应然后图像存在然后我得到错误代码516（已经存在图像）所以请在得到回复后帮助我。 我想要替换旧图像或删除旧图像。

  func setUI() {
    self.btnCancel.layer.borderWidth  = 1.0
    self.btnCancel.layer.cornerRadius = 3.0
    self.btnCancel.addShadowView()
    print("-------------------------------- method Call")
    if let url = NSURL(string: strFileName) {
        print(url)
        let destination = Alamofire.Request.suggestedDownloadDestination(directory: .DocumentDirectory, domain: .UserDomainMask)
        self.request =  Alamofire.download(.GET, url, parameters: nil, encoding: ParameterEncoding.URL,destination:destination)
            .progress { bytesRead, totalBytesRead, totalBytesExpectedToRead in
                dispatch_async(dispatch_get_main_queue()) {
                    print("Total bytes read on main queue: \(totalBytesRead)")
                    print("Progress on main queue: \(Float(totalBytesRead) / Float(totalBytesExpectedToRead))")
                    print("totalBytesExpectedToRead",totalBytesExpectedToRead)

                    self.CountPercentage.text! = String(format: "%.f%%",self.viewProgressBar.progress * 100)
                    self.viewProgressBar.progress = (Float(totalBytesRead) / Float(totalBytesExpectedToRead))
                }
            }
            .response { request, response, _, error in
                print("\(request?.URL)")  // original URL request
                print(error)
                if !(error == nil) {
                    if !(error!.code != NSURLErrorCancelled) {
                        print("cancel----------")
                    } else if (error!.code == 516) {
                        print("fileURL: \(destination(NSURL(string: "")!, response!))")
                        let filePath = destination(NSURL(string: "")!, response!)
                        self.alertAction("File downloaded successfully.", filePath: filePath)
                    } else {
                        CommonMethods.sharedInstance.showAlertWithMessage((error?.localizedDescription)!, withController: self)
                    }
                } else {
                    print("fileURL: \(destination(NSURL(string: "")!, response!))")
                    let filePath = destination(NSURL(string: "")!, response!)
                    self.alertAction("File downloaded successfully.", filePath: filePath)
                }
        }
    }
}