ios - 尝试使用 FileManager 复制文件时出错 : Operation not permitted

Question

我是 iOS 中文件管理器的新手。我正在尝试创建一个简单的应用程序:有一个文件列表，当用户按下某个单元格时，文件将打开。用户还可以添加新文件。

不久前我asked a question关于我遇到的另一个错误，我得到了 answer that work on a simulator ，但它在真实设备上不起作用!

我的代码:(错误在 storeAndShare() 中)

typealias UrlLink = String

extension UrlLink {
var url: URL {
    var url = try! FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
    url.appendPathComponent(self)
    return url
}
}

class TableViewController: UITableViewController, UIDocumentPickerDelegate {

var names: [UrlLink] = []

override func viewDidLoad() {
    super.viewDidLoad()

    // Uncomment the following line to preserve selection between presentations
    // self.clearsSelectionOnViewWillAppear = false

    // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
     self.navigationItem.rightBarButtonItem = self.editButtonItem
}

func urlForFilename(_ filename: String) -> URL {
    var url = try! FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
    url.appendPathComponent(filename)
    return url
}

@IBAction func newButtonPressed(_ sender: Any) {
    let types = UTType(tag: "pdf", tagClass: .filenameExtension, conformingTo: nil)!
    let controller = UIDocumentPickerViewController(forOpeningContentTypes: [types])
    controller.delegate = self
    self.present(controller, animated: true, completion: nil)
}

func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
    for url in urls {
        self.storeAndShare(withURL: url)
    }
}

// MARK: - Table view data source

override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
    if editingStyle == .delete {
        let removedName = self.names.remove(at: indexPath.row)
        do {
            try FileManager.default.removeItem(atPath: removedName.url.path)
        } catch let err {
            print("Error while trying to remove the file \(err)")
        }
        
        tableView.deleteRows(at: [indexPath], with: .automatic)
    }
}

override func numberOfSections(in tableView: UITableView) -> Int {
    // #warning Incomplete implementation, return the number of sections
    return 1
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    // #warning Incomplete implementation, return the number of rows
    return names.count
}

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = UITableViewCell(style: .default, reuseIdentifier: nil)

    cell.textLabel?.text = names[indexPath.row]
    
    if FileManager.default.fileExists(atPath: names[indexPath.row].url.path) {
        cell.accessoryType = .disclosureIndicator
    } else {
        cell.accessoryType = .none
    }

    return cell
}

lazy var documentInteractionController: UIDocumentInteractionController = {
    let vc = UIDocumentInteractionController()
    vc.delegate = self
    return vc
}()

func getSelf() -> TableViewController {
    return self
}

func share(url: URL) {
    documentInteractionController.url = url
    documentInteractionController.uti = url.typeIdentifier ?? "public.data, public.content"
    documentInteractionController.name = url.localizedName ?? url.lastPathComponent
    documentInteractionController.presentPreview(animated: true)
}

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    share(url: self.names[indexPath.row].url)
}

func storeAndShare(withURL url: URL) {

    let directoryURL = try! FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
    var newURL = directoryURL.appendingPathComponent(url.lastPathComponent)
    
    var index = 1
    let originalNewURL = newURL
    while FileManager.default.fileExists(atPath: newURL.path) {
        newURL = originalNewURL
        let comp: NSString = newURL.lastPathComponent as NSString
        newURL.deleteLastPathComponent()
        let newName: String = "\(comp.deletingPathExtension) \(index).\(comp.pathExtension)"
        newURL.appendPathComponent(newName)
        index = index + 1
    }
    
    do {
        try FileManager.default.copyItem(at: url, to: newURL)
        DispatchQueue.main.async { [self] in
            names.append(newURL.lastPathComponent)
            tableView.insertRows(at: [IndexPath(row: names.count - 1, section: 0)], with: .automatic)
        }
    } catch {
        print("ERROR: \(error).") // ERROR: Error Domain=NSCocoaErrorDomain Code=257 "The file “I am a file and you put documents in me.pdf” couldn’t be opened because you don’t have permission to view it." UserInfo={NSFilePath=/private/var/mobile/Library/Mobile Documents/com~apple~CloudDocs/תיקיות/I am a file and you put documents in me.pdf, NSUnderlyingError=0x281ab2790 {Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted"}}.
    }
}

}

extension TableViewController: UIDocumentInteractionControllerDelegate {
/// If presenting atop a navigation stack, provide the navigation controller in order to animate in a manner consistent with the rest of the platform
func documentInteractionControllerViewControllerForPreview(_ controller: UIDocumentInteractionController) -> UIViewController {
    guard let navVC = self.navigationController else {
        return self
    }
    return navVC
}
}
extension URL {
var typeIdentifier: String? {
    return (try? resourceValues(forKeys: [.typeIdentifierKey]))?.typeIdentifier
}
var localizedName: String? {
    return (try? resourceValues(forKeys: [.localizedNameKey]))?.localizedName
}
}

基本上，当用户添加新文件时，我的应用程序会尝试将其复制到文档文件夹中，以便将其存储在那里。

尝试将所选文件复制到文档文件夹时出现以下错误:

Error Domain=NSCocoaErrorDomain Code=257 "The file “I am a file and you put documents in me.pdf” couldn’t be opened because you don’t have permission to view it." UserInfo={NSFilePath=/private/var/mobile/Library/Mobile Documents/com~apple~CloudDocs/תיקיות/I am a file and you put documents in me.pdf, NSUnderlyingError=0x281ab2790 {Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted"}}

我似乎没有查看该文件的权限。但这很奇怪，因为我刚刚使用 UIDocumentInteractionController 选择了文件，并且正如我之前所说，它在模拟器上运行良好。

如何获得复制文件的权限？提前致谢!

Answer 1

我也遇到了同样的问题，按照@Cameron的回答here ,

简而言之，您需要做的就是包装处理文件的代码部分，如下所示:

func readFile(url: URL){
    // `url` to the directory or file you are trying to access.
    url.startAccessingSecurityScopedResource()

    // deal with your file here

    url.stopAccessingSecurityScopedResource()
}

Apple Official Documentation

就您而言，应该是:

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = UITableViewCell(style: .default, reuseIdentifier: nil)

    cell.textLabel?.text = names[indexPath.row]

    // newly added    
    names[indexPath.row].url.startAccessingSecurityScopedResource()

    if FileManager.default.fileExists(atPath: names[indexPath.row].url.path) {
        cell.accessoryType = .disclosureIndicator
    } else {
        cell.accessoryType = .none
    }
    // newly added
    names[indexPath.row].url.stopAccessingSecurityScopedResource()

    return cell
}