下载PDF文件并保存在文档目录中

Question

class ViewController: UIViewController {

    @IBOutlet weak var progressView: UIProgressView!

    override func viewDidLoad() {
        let _ = DownloadManager.shared.activate()
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        DownloadManager.shared.onProgress = { (progress) in
            OperationQueue.main.addOperation {
                self.progressView.progress = progress
            }
        }
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        DownloadManager.shared.onProgress = nil
    }

    @IBAction func startDownload(_ sender: Any) {
        let url = URL(string: "https://d0.awsstatic.com/whitepapers/KMS-Cryptographic-Details.pdf")!
        let task = DownloadManager.shared.activate().downloadTask(with: url)
        task.resume()
    }
}

文件当前将转到：文件：///users/cybermac/library/developer/coresimulator/devices/caec75d0-423a-4fb2-b0d6-9e7cadb190a1/data/containers/data/application/8b5cbfc8-7058-48db-a1c4-872302a80610/library/caches/com.apple.nsurlsessiond/downloads/com.example.downloadtaskexample/cfnetworkdownload_q7ovlf.tmp

如何将其保存在/documents/中？

类似于以下内容:文件：///users/cybermac/library/developer/coresimulator/devices/CAEC75D0-423A-4FB2-B0D6-9E7CADB190A1/data/containers/data/application/64370B29-2C01-470F-AE76-17EF1A7BC918/documents/

其想法是，保存在该目录中的文件可以用于脱机读取（使用PDFKit或webKit）。只有在应用程序被删除的情况下才会被删除。




Answer 1

下载后需要将文件移动到自定义位置。实现URLSessionDownloadDelegate，您将收到下载文件的位置。

委托方法：

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

移动文件的代码：

do {
    let documentsURL = try
        FileManager.default.url(for: .documentDirectory,
                                in: .userDomainMask,
                                appropriateFor: nil,
                                create: false)

    let savedURL = documentsURL.appendingPathComponent("yourCustomName.pdf")
    try FileManager.default.moveItem(at: location, to: savedURL)
} catch {
    print ("file error: \(error)")
}