1

我有一个采用 NSFilePresenter 协议的 UIViewController。我已经实现了presentedItemDidChange() 以便接收存储在iCloud 上无处不在的容器中的文件的更改。我的实现在 iOS13.7 上运行良好，但在 iOS 14 上失败。

当我从 macOS 上的“Finder”之类的外部进程修改呈现的文件时，不会调用 presentItemDidChange()。

如果这是 iOS 14 中的一个已知错误，还是我在实现中遗漏了什么？

我的实现大致是这样的：

var m_basename = "textfile.txt"

var iCloudURL: URL?  {
  get {
    guard let iCloudDocumentsBaseURL = FileManager.default.url(forUbiquityContainerIdentifier: iCloudContainerId) else {
      return nil
    }
    let iCloudDocumentsURL = iCloudDocumentsBaseURL.appendingPathComponent("Documents").appendingPathComponent(m_basename)
    return iCloudDocumentsURL
  }
}

override func viewDidLoad() {
  super.viewDidLoad()
  // Do any additional setup after loading the view.
  
  NSFileCoordinator.addFilePresenter(self)

  /* do some iCloud availability check here ; not shown */

  save(text: "Test string") { (success) in
    if success {
      print(#function, "Wrote file successfully")
    } else {
      print(#function, "Write file failed")
    }
  }
}

public func save(text: String, completion: @escaping (Bool) -> Void) {
  if let presenterurl = self.presentedItemURL {
    var errorMain: NSError?

    // set presenter if we load a file that is currently being presented
    var filePresenter: NSFilePresenter? = nil
    if presenterurl == iCloudURL {
      filePresenter = fPresenter
    }

    let coord = NSFileCoordinator(filePresenter: filePresenter)
    coord.coordinate(writingItemAt: activeURL, options: .forReplacing, error: &errorMain) { (writeUrl) in
      do {
        try text.write(toFile: writeUrl.path, atomically: true, encoding: String.Encoding.utf8)
        print(#function, "\(writeUrl) write OK")
        completion(true)
      } catch {
        print(#function, "\(writeUrl) write failed: \(error.localizedDescription)")
        completion(false)
      }
    }
    if errorMain != nil {
      print("Error: ", errorMain!.localizedDescription)
      completion(false)
    }
  }
  print(#function, "end of save() function")
}

// MARK: - NSFilePresenter
extension ViewController: NSFilePresenter {
  public var presentedItemURL: URL? {
      return iCloudURL
  }
  
  public var presentedItemOperationQueue: OperationQueue {
    return OperationQueue.main
  }
  
  public func presentedItemDidChange() {
    print(#function, "Loading file \(m_basename)")
  }
}

谢谢

4

0 回答 0