startAccessingSecurityScopedResource（）return always false

Question

当我尝试从iCloud Drive或Dropbox将文件导入服务器时，startAccessingSecurityScopedResource()仅返回false设备，但在模拟器（Xcode 8，Swift 2.3，minimum target 8.0）中测试时返回true。

这是我的代码：

{ 
     func showCloudDriveAction(inputBar: NAChatInputBar) { 
      let documentmenuPicker = UIDocumentMenuViewController(documentTypes: ["public.data"], inMode: .Import) 
      documentmenuPicker.delegate = self 
      presentViewController?.presentViewController(documentmenuPicker, animated: true, completion: nil) 
     } 

} 

extension NAChatInputBarPresenter: UIDocumentPickerDelegate, UIDocumentMenuDelegate { 

    public func documentMenu(documentMenu: UIDocumentMenuViewController, didPickDocumentPicker documentPicker: UIDocumentPickerViewController) { 
     documentPicker.delegate = self 
     self.presentViewController?.presentViewController(documentPicker, animated: true, completion: nil) 
    } 

    public func documentPicker(controller: UIDocumentPickerViewController, didPickDocumentAtURL url: NSURL) { 
     if url.startAccessingSecurityScopedResource() { 
      guard let path = url.path, data = NSData(contentsOfFile: path) else { 
       return 
      } 
      delegate?.chatInputBarPresenter(data, atUrl: url) 
      url.stopAccessingSecurityScopedResource() 
     } 
    } 

} 

Answer 1

startAccessingSecurityScopedResource没有返回true它只是需要与stopAccessingSecurityScopedResource()配对。

如果返回false你仍然可以使用一个NSFileCoordinator访问资源。

let isSecuredURL = url.startAccessingSecurityScopedResource() == true 
let coordinator = NSFileCoordinator() 
var error: NSError? = nil 
coordinator.coordinate(readingItemAt: url, options: [], error: &error) { (url) -> Void in 
    do { 
     // do something 
    } catch (_) { 
     // something went wrong 
    } 
} 
if (isSecuredURL) { 
    url.stopAccessingSecurityScopedResource() 
}