标签：swift nsurlconnecttion 同步 异步
原创blog，转载请注明出处
http://blog.csdn.net/hello_hwc
一、同步异步两个概念
简单来讲，同步就是函数或者闭包（objective c中的block）执行完毕才能返回。异步是立刻返回，然后异步执行的动作结束后，再进行回调。class func sendSynchronousRequest(_ request: NSURLRequest, returningResponse response:AutoreleasingUnsafeMutablePointer<NSURLresponse> error error:NSErrorPointer)->NSdata?参数：
class ViewController: UIViewController{
var imageview = UIImageView(frame: CGRectMake(40,40,200,200))
override func viewDidLoad(){
super.viewDidLoad()
imageview.contentMode = UIViewContentMode.ScaleAspectFit
self.view.addSubview(imageview)
let url = "http://f.hiphotos.baidu.com/image/pic/item/e1fe9925bc315c60191d32308fb1cb1348547760.jpg"
let imageURL = NSURL(string:url)
let urlRequest = NSURLRequest(URL: imageURL!)
var response:NSURLResponse?
var error:NSError?
var data = NSURLConnection.sendSynchronousRequest(urlRequest,returningResponse:&response,error:&error) as NSData?
if error == nil && data?.length > 0{
var image:UIImage = UIImage(data:data!)!
imageview.image = image
}
}
override func didReceiveMemoryWarning(){
super.didReceiveMemoryWarning()
}
}class func sendAsynchronousRequest(_ request: NSURLRequest, queue:NSOperationQueue! completionHandler handler:(NSURLResponse!,NSData!,NSError!))->Void参数：
class ViewController: UIViewController{
var imageview = UIImageView(frame: CGRectMake(40,40,200,200))
override func viewDidLoad(){
super.viewDidLoad()
imageview.contentMode = UIViewContentMode.ScaleAspectFit
self.view.addSubview(imageview)
let url = "http://f.hiphotos.baidu.com/image/pic/item/e1fe9925bc315c60191d32308fb1cb1348547760.jpg"
let imageURL = NSURL(string:url)
let urlRequest = NSURLRequest(URL: imageURL!)
NSURLConnection.sendAsynchronousRequest(urlRequest,queue:NSOperationQueue.mainQueue(),completionHandler:{
(response: NSURLResponse!,data:NSData!,error:NSError!)-> Void in
if error == nil && data?.length > 0{
var image:UIImage = UIImage(data:data!)!
self.imageview.image = image
}
})
}
override func didReceiveMemoryWarning(){
super.didReceiveMemoryWarning()
}
}
下载的图片原图
Swift中利用NSURLConnection进行同步异步下载(实例解析)
标签：swift nsurlconnecttion 同步 异步
原文地址：http://blog.csdn.net/hello_hwc/article/details/41006531
