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）

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）

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

{   
 "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": ""
        }
    ]
}