SwiftData误差NSFileManager

Question

我正在将SwiftData从SWIFT1.2更新到Swift 2，经过一些更改和修正后，我仍然有一个错误，我无法理解为什么会发生这种错误。

守则如下：

    public static func saveUIImage(image: UIImage) -> String? {

    let docsPath = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true)[0] as String
    let imageDirPath = docsPath.stringByAppendingPathComponent("SwiftDataImages")

    if !NSFileManager.defaultManager().fileExistsAtPath(imageDirPath) {

        do {
            try NSFileManager.defaultManager().createDirectoryAtPath(imageDirPath, withIntermediateDirectories: false, attributes: [:])
        } catch {
            print("Error creating SwiftData image folder")
            return nil
        }

    }

    let imageID = NSUUID().UUIDString
    let imagePath = (imageDirPath as NSString).stringByAppendingPathComponent(imageID)
    let imageAsData = UIImagePNGRepresentation(image)
    if !imageAsData!.writeToFile(imagePath, atomically: true) {
        print("Error saving image")
        return nil
    }
    return imageID

}

在“do{”行上，Xcode抛出以下错误：

不能使用类型的参数列表调用“createDirectoryAtPath”(String，withIntermediateDirectories: Bool，attributes：_，error：_)

知道为什么会发生这种事吗？快把我逼疯了。

致以良好的问候，并提前表示感谢。

;)

Answer 1

在我的Xcode 7.2中没有：

let imageDirPath = docsPath.stringByAppendingPathComponent("SwiftDataImages")

所以我尝试了这段代码，它编译得很好：

public func saveUIImage(image: UIImage) -> String? {

    let docsPath = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true)[0] as String
    let imageDirPath = NSURL(string: docsPath)?.URLByAppendingPathComponent("SwiftDataImages")

    if !NSFileManager.defaultManager().fileExistsAtPath(imageDirPath!.absoluteString) {

        do {
            try NSFileManager.defaultManager().createDirectoryAtPath(imageDirPath!.absoluteString, withIntermediateDirectories: false, attributes: [:])
        } catch {
            print("Error creating SwiftData image folder")
            return nil
        }

    }

    let imageID = NSUUID().UUIDString
    let imagePath = (imageDirPath!.absoluteString as NSString).stringByAppendingPathComponent(imageID)
    let imageAsData = UIImagePNGRepresentation(image)
    if !imageAsData!.writeToFile(imagePath, atomically: true) {
        print("Error saving image")
        return nil
    }
    return imageID
}

Answer 2

苹果强烈建议使用NSFileManager和NSData的URL相关API

public func saveUIImage(image: UIImage) -> String? {

  let fileManager = NSFileManager.defaultManager()
  let docsURL = try! fileManager.URLForDirectory(.DocumentDirectory, inDomain: .UserDomainMask, appropriateForURL: nil, create: false)
  let imageDirURL = docsURL.URLByAppendingPathComponent("SwiftDataImages")

  if !fileManager.fileExistsAtPath(imageDirURL.path!) {
    do {
      try fileManager.createDirectoryAtURL(imageDirURL, withIntermediateDirectories: false, attributes:nil)
    } catch let error as NSError{
      print("Error creating SwiftData image folder", error)
      return nil
    }
  }

  let imageID = NSUUID().UUIDString
  let imageURL = imageDirURL.URLByAppendingPathComponent(imageID)
  let imageAsData = UIImagePNGRepresentation(image)
  if !imageAsData!.writeToURL(imageURL, atomically: true) {
    print("Error saving image")
    return nil
  }
  return imageID
}