swift基础值网络请求

NSURLSessionDownloadDelegate

class ViewController: UIViewController, NSURLSessionDownloadDelegate {

var session = NSURLSession()

@IBOutlet weak var imagen: UIImageView!
@IBOutlet weak var progreso: UIProgressView!

@IBAction func cargar(sender: UIButton) {
let imageUrl: NSString = "http://c.hiphotos.baidu.com/image/pic/item/8cb1cb13495409235fa14adf9158d109b2de4942.jpg"
let getImageTask: NSURLSessionDownloadTask =
session.downloadTaskWithURL(NSURL(string: imageUrl as String)!)
getImageTask.resume()
}

override func viewDidLoad() {
super.viewDidLoad()
let sessionConfig =
NSURLSessionConfiguration.defaultSessionConfiguration()
session = NSURLSession(configuration: sessionConfig, delegate: self, delegateQueue: nil)
}

override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}

func URLSession(session: NSURLSession, downloadTask: NSURLSessionDownloadTask, didFinishDownloadingToURL location: NSURL){
print("Download finished")
let downloadedImage = UIImage(data: NSData(contentsOfURL: location)!)
dispatch_async(dispatch_get_main_queue(), {() in
self.imagen.image = downloadedImage
})
}

func URLSession(session: NSURLSession, downloadTask: NSURLSessionDownloadTask, didWriteData bytesWritten: Int64,totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64){
dispatch_async(dispatch_get_main_queue(), {() in
let variable = Float(totalBytesWritten)/Float(totalBytesExpectedToWrite)
self.progreso.progress = variable
}) }

}


NSURLSession

import UIKit

class ViewController: UIViewController {

@IBOutlet weak var city: UILabel!
@IBOutlet weak var temperatureCelsius: UITextField!
@IBOutlet weak var temperatureCelsiusMax: UITextField!
@IBOutlet weak var temperatureCelsiusMin: UITextField!
@IBOutlet weak var temperatureKelvin: UITextField!
@IBOutlet weak var temperatureKelvinMax: UITextField!
@IBOutlet weak var temperatureKelvinMin: UITextField!
@IBOutlet weak var humidity: UITextField!
@IBOutlet weak var wind: UITextField!

override func viewDidLoad() {
super.viewDidLoad()

let sessionConfig: NSURLSessionConfiguration = NSURLSessionConfiguration.defaultSessionConfiguration()
sessionConfig.allowsCellularAccess = false
//only accept JSON answer
sessionConfig.HTTPAdditionalHeaders = ["Accept":"application/json"]
//timeouts and connections allowed
sessionConfig.timeoutIntervalForRequest = 30.0
sessionConfig.timeoutIntervalForResource = 60.0
sessionConfig.HTTPMaximumConnectionsPerHost = 1
//create session, assign configuration
let session = NSURLSession(configuration: sessionConfig)
session.dataTaskWithURL(NSURL(string: "http://api.openweathermap.org/data/2.5/weather?q=Barcelona,es&appid=2de143494c0b295cca9337e1e96b00e0")!, completionHandler: {(data, response, error) in
let dic:NSDictionary = (try? NSJSONSerialization.JSONObjectWithData(data!, options:NSJSONReadingOptions(rawValue: 0))) as? NSDictionary ?? [String:String]()

if dic.count == 0 {
return
}

print(dic)

let city: NSString = (dic["name"] as! NSString)
let kelvin: AnyObject! = (dic["main"] as! NSDictionary) ["temp"]
let kelvin_min: AnyObject! = (dic["main"] as! NSDictionary) ["temp_min"]
let kelvin_max: AnyObject! = (dic["main"] as! NSDictionary) ["temp_max"]
let celsius = kelvin as! Float - 274.15 as Float
let celsius_min = kelvin_min as! Float - 274.15 as Float
let celsius_max = kelvin_max as! Float - 274.15 as Float
let humidity: AnyObject! = (dic ["main"] as! NSDictionary) ["humidity"]
let wind: AnyObject! = (dic ["wind"] as! NSDictionary) ["speed"]

//original thread
dispatch_async(dispatch_get_main_queue(), { () in
self.city.text = "\(city)"
self.temperatureCelsius.text = "\(celsius)"
self.temperatureCelsiusMax.text = "\(celsius_max)"
self.temperatureCelsiusMin.text = "\(celsius_min)"
self.temperatureKelvin.text = "\(kelvin)"
self.temperatureKelvinMax.text = "\(kelvin_max)"
self.temperatureKelvinMin.text = "\(kelvin_min)"
self.humidity.text = "\(humidity)"
self.wind.text = "\(wind)"
})
}).resume()
}

override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}

}