NSFileManager.defaultManager（）。createFileAtPath（）返回false

Question

之后就像一千个print()声明，我终于找到了问题！但是，我不知道如何解决它。问题就出在这行：

NSFileManager.defaultManager().createFileAtPath(savePath, contents: data, attributes: nil)

根据苹果开发者指南，这行代码returns true if the operation was successful or if the item already exists, otherwise false.

此行返回一个false，我不知道是什么原因，因为代码前面该行似乎没问题。任何人有关于如何解决这个错误的建议？

的代码的其余部分是在这里：

// 
// ViewController.swift 
// Downloading An Image From The Web 
// 
// Created by Jae Hyun Kim on 9/6/15. 
// Copyright © 2015 Jae Hyun Kim. All rights reserved. 
// 

import UIKit 

class ViewController: UIViewController { 

    @IBOutlet weak var image: UIImageView! 

    override func viewDidLoad() { 
     super.viewDidLoad() 
     let url = NSURL(string: "http://7-themes.com/data_images/out/3/6776407-beautiful-scenery-pictures.jpg") 
     let urlRequest = NSURLRequest(URL: url!) 

     let task = NSURLSession.sharedSession().dataTaskWithRequest(urlRequest, completionHandler: { (data, response, error) -> Void in 
      if error != nil { 
       print(error) 
      } 
      else { 
       if let bach = UIImage(data: data!) { 
        //self.image.image = bach 
        let documentsDirectory:String? 
        let paths:[AnyObject] = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.PicturesDirectory, NSSearchPathDomainMask.UserDomainMask, true) 
        print(paths) 
        if paths.count > 0 { 
         documentsDirectory = paths[0] as? String 
         let savePath = documentsDirectory! + "/bach.jpg" 

         print(NSFileManager.defaultManager().createFileAtPath(savePath, contents: data, attributes: nil)) 

         if NSFileManager.defaultManager().fileExistsAtPath(savePath) { 
          print("file available") 
         } 
         else { 
          print("file not available") 
         } 



         self.image.image = UIImage(contentsOfFile: savePath) 
        } 
       } 
      } 
     }) 
     task!.resume() 
    } 

    override func didReceiveMemoryWarning() { 
     super.didReceiveMemoryWarning() 
     // Dispose of any resources that can be recreated. 
    } 
} 

Answer 1

import UIKit 

class ViewController: UIViewController { 
    @IBOutlet weak var image: UIImageView! 
    override func viewDidLoad() { 
     super.viewDidLoad() 

     let url = NSURL(string: "http://7-themes.com/data_images/out/3/6776407-beautiful-scenery-pictures.jpg")! 
     let urlRequest = NSURLRequest(URL: url) 

     let task = NSURLSession.sharedSession().dataTaskWithRequest(urlRequest, completionHandler: { (data, response, error) -> Void in 


      // you should always do it from the main queue otherwise you will experience a big delay when trying to display your image 
      dispatch_async(dispatch_get_main_queue()) { 
       // unwrap your data 
       if let data = data { 
        print(data.length) 
        // get your caches directory URL 
        let cachesDirectory = try! NSFileManager().URLForDirectory(.CachesDirectory, inDomain: .UserDomainMask, appropriateForURL: nil, create: true) 
        // create your local file url by appending your url last path component 
        let fileUrl = cachesDirectory.URLByAppendingPathComponent(url.lastPathComponent!) 
        // save downloaded data to disk 
        if data.writeToURL(fileUrl, atomically: true) { 
         print(true) 
         // load your saved image from disk 
         self.image.image = UIImage(contentsOfFile: fileUrl.path!) 
        } 

       } 
      } 

     }) 
     task.resume() 
    } 
    override func didReceiveMemoryWarning() { 
     super.didReceiveMemoryWarning() 
     // Dispose of any resources that can be recreated. 
    } 
} 

注意，您将需要编辑您的plist如下：