Loading/Downloading image from URL on Swift

Question

I\'d like to load an image from a URL in my application, so I first tried with Objective-C and it worked, however, with Swift, I\'ve a compilation error:

Answer 1

I wrapped the code of the best answers to the question into a single, reusable class extending UIImageView, so you can directly use asynchronous loading UIImageViews in your storyboard (or create them from code).

Here is my class:

import Foundation
import UIKit

class UIImageViewAsync :UIImageView
{

    override init()
    {
        super.init(frame: CGRect())
    }

    override init(frame:CGRect)
    {
        super.init(frame:frame)
    }

    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    func getDataFromUrl(url:String, completion: ((data: NSData?) -> Void)) {
        NSURLSession.sharedSession().dataTaskWithURL(NSURL(string: url)!) { (data, response, error) in
            completion(data: NSData(data: data))
        }.resume()
    }

    func downloadImage(url:String){
        getDataFromUrl(url) { data in
            dispatch_async(dispatch_get_main_queue()) {
                self.contentMode = UIViewContentMode.ScaleAspectFill
                self.image = UIImage(data: data!)
            }
        }
    }
}

and here is how to use it:

imageView.downloadImage("http://www.image-server.com/myImage.jpg")