iOS快速将视频从URL下载到电话库

Question

我正在使用URLSessionDownloadTask将视频从url下载到我的手机图库中，如何设置下载的视频文件的目标路径，我需要将其显示在“手机视频”文件夹中。

var downloadTask: URLSessionDownloadTask!
var backgroundSession: URLSession!

if let theUrl = url {

  downloadTask = backgroundSession.downloadTask(with: theUrl)
  downloadTask.resume()
}

extension DownloadVideoViewController : URLSessionDownloadDelegate {


    func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) {

        if self.downloadTask != nil {
            self.displyAlertWithAction(title: "Complete", message: "Download finished")
        }
    }


    func urlSession(_ session: URLSession,downloadTask: URLSessionDownloadTask,didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64)
    {
        print("\nDownload started ....Total is \(Float(totalBytesExpectedToWrite)/(1024*1024)) Mb")
        print("\nWritten \(totalBytesWritten) bytes")
        progressView.setProgress(Float(totalBytesWritten)/Float(totalBytesExpectedToWrite), animated: true)
    }

    func urlSession(_ session: URLSession,task: URLSessionTask,didCompleteWithError error: Error?)
    {
        if (error != nil) {
            print(error!.localizedDescription)
        }else{
            if downloadTask != nil {
                print("The task finished transferring data successfully")
                downloadTask = nil
                progressView.setProgress(0.0, animated: true)
            }

        }
    }

}

Answer 1

您可以像下面的代码示例一样设置目标路径。

func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) {

   let url = downloadTask.response?.url?.lastPathComponent

   if (url?.hasSuffix(".mp4"))! // for check video download
   {

    SVProgressHUD.dismiss() // dismiss the HUD
    guard let documentsDirectoryURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else { return }

    if !FileManager.default.fileExists(atPath: documentsDirectoryURL.appendingPathComponent((downloadTask.response?.url?.lastPathComponent)!).path) {    // the video already exist in path

        // create a deatination url with the server response suggested file name

        let destinationURL = documentsDirectoryURL.appendingPathComponent(downloadTask.response?.suggestedFilename ?? ((downloadTask.response?.url)?.lastPathComponent)!)

        do {

            try FileManager.default.moveItem(at: location, to: destinationURL)


            PHPhotoLibrary.requestAuthorization({(authorizationStatus: PHAuthorizationStatus) -> Void in

                var identifier = ""

                // check if user authorized access photos for your app
                if authorizationStatus == .authorized {
                    PHPhotoLibrary.shared().performChanges({

                        let createassetrequest = PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: destinationURL)
                        let assetplaceholder = createassetrequest?.placeholderForCreatedAsset

                        let albumchange = PHAssetCollectionChangeRequest(for: self.assetcol.assetCollection)
                        albumchange?.addAssets([assetplaceholder as Any] as NSArray)

                        identifier = (assetplaceholder?.localIdentifier)!
                        print(identifier)

                    })
                    {  completed, error in
                        if completed {

                            DispatchQueue.main.async {

                                print("Video saved") // successfully saved video in your gallery
                            }

                        } else {
                            print(error as Any)
                        }
                    }
                }
            })

        } catch { print(error) }

    }
    else // video not already exist in this destination path.
    {

        SVProgressHUD.dismiss()

        let destinationURL = documentsDirectoryURL.appendingPathComponent(downloadTask.response?.suggestedFilename ?? ((downloadTask.response?.url)?.lastPathComponent)!)

        do {

            try FileManager.default.removeItem(at: destinationURL)
            try FileManager.default.moveItem(at: location , to: destinationURL)

            PHPhotoLibrary.requestAuthorization({ (authorizationStatus: PHAuthorizationStatus) -> Void in

                var identifier = ""
                // check if user authorized access photos for your app
                if authorizationStatus == .authorized {
                    PHPhotoLibrary.shared().performChanges({

                        let createassetrequest = PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: destinationURL)
                        let assetplaceholder = createassetrequest?.placeholderForCreatedAsset

                        let albumchange = PHAssetCollectionChangeRequest(for: self.assetcol.assetCollection)
                        albumchange?.addAssets([assetplaceholder as Any] as NSArray)

                        identifier = (assetplaceholder?.localIdentifier)!
                        print(identifier)

                      }) { completed, error in
                        if completed {

                            DispatchQueue.main.async {

                                print("Video saved") // saved video successfully.

                            }

                        } else {
                            print(error as Any)
                        }
                    }
                }
            })

        } catch { print(error) }

    }
}
else // something like image if not video
{

}

  }


func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) {

    DispatchQueue.main.async {

        let progress = Float(totalBytesWritten) / Float(totalBytesExpectedToWrite)
        SVProgressHUD.showProgress(progress, status: "Downloading")

    }
}
}

我希望它将对您有帮助。