在一千个print()语句之后,我终于找到了问题！但是,我不确定如何解决它.问题在于：
NSFileManager.defaultManager().createFileAtPath(savePath,contents：data,attributes：nil)
根据Apple开发人员指南,如果操作成功或项目已存在,则此行代码返回true,否则返回false.
这行返回false,我不确定为什么,因为行前面的代码似乎没问题.有人对如何解决这个bug有任何建议吗？
其余的代码在这里：
//
// 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.
}
}
解决方法
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,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.
}
}
请注意,您需要编辑您的plist,如下所示：
