Swift - 异步获取网络数据封装类

使用NSURLConnection.sendAsynchronousRequest()可以采用异步获取的方式取得数据。下面通过对数据获取类进行封装，演示如何进行数据请求与接收。

1，HttpController.swift （数据获取封装类，结果处理协议）

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import UIKit   //自定义http协议 protocol HttpProtocol{     //定义一个方法接收一个字典     func didRecieveResults(resultes:NSDictionary) } class HttpController:NSObject{     //定义一个可选代理     var delegate:HttpProtocol?           //定义一个方法运过来获取网络数据，接收参数为网址           func onSearch(url:String){         //定义一个NSURL         var nsUrl:NSURL=NSURL(string: url)!         //定义一个NSURLRequest         var request:NSURLRequest=NSURLRequest(URL: nsUrl)         //异步获取数据         NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.mainQueue(),             completionHandler: {(response:NSURLResponse!,data:NSData!,error:NSError!)->Void in             //由于我们获取的数据是json格式，所以我们可以将其转化为字典。             var jsonResult:NSDictionary=NSJSONSerialization.JSONObjectWithData(data,                 options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary             //将数据传回给代理             self.delegate?.didRecieveResults(jsonResult)         })     } }

2，ViewController.swift （使用样例）

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import UIKit   class ViewController: UIViewController,HttpProtocol {           //获取网络数据的类     var eHttp:HttpController = HttpController()     //接收频道列表的数组     var channelData:NSArray=NSArray()       override func viewDidLoad() {         super.viewDidLoad()         // Do any additional setup after loading the view, typically from a nib.                   //为HttpController实例设置代理         eHttp.delegate=self         //获取频道数据         eHttp.onSearch("http://www.douban.com/j/app/radio/channels")       }       override func didReceiveMemoryWarning() {         super.didReceiveMemoryWarning()         // Dispose of any resources that can be recreated.     }           //实现HttpProtocol协议的方法     func didRecieveResults(results:NSDictionary){         if (results["channels"] != nil){             //如果channels关键字的value不为nil，获取的就是频道数据             self.channelData=results["channels"] as NSArray             println(self.channelData[0]["name"] as String) //私人兆赫                       }     } }

3，请求数据样例

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{    "channels": [         {             "name_en": "Personal Radio",             "seq_id": 0,             "abbr_en": "My",             "name": "私人兆赫",             "channel_id": 0         },         {             "name": "华语",             "seq_id": 0,             "abbr_en": "",             "channel_id": "1",             "name_en": ""         },         {             "name": "欧美",             "seq_id": 1,             "abbr_en": "",             "channel_id": "2",             "name_en": ""         }     ] }