Return value from completion handler - Swift

Question

I\'m using a loadImage method in a Utilities class and am having some trouble with returning images via closures. Basically because my code could return either an image or a

Answer 1

Add a handler to your loadImage func:

Swift 3

 func loadImage(_ urlString: String, handler:@escaping (_ image:UIImage?)-> Void)
    {

        let imageURL: URL = URL(string: urlString)!

        URLSession.shared.dataTask(with: imageURL) { (data, _, _) in
            if let data = data{
                handler(UIImage(data: data))
            }
        }.resume()
    }

Call func like this:

loadImage("SomeURL") { (image) -> Void in
            if let image = image{
                DispatchQueue.main.async {
                    self.imageView.image = image
                }
            }
        }

Swift 2.3

func loadImage(urlString: String, handler: (image:UIImage?)-> Void)
    {

        let imageURL: NSURL = NSURL(string: urlString)!

        NSURLSession.sharedSession().dataTaskWithURL(imageURL) { (data, _, _) in
            if let data = data{
                handler(image: UIImage(data: data))
            }
            }.resume()
    }

Call func like this:

  loadImage("someURL") { (image) -> Void in
            if let image = image{
                dispatch_async(dispatch_get_main_queue()) {
                    self.imageView.image = image
                }
            }
        }

Answer 2

I would do it this way:

public class UtilitiesService: NSObject {
    public class func loadImage(urlString:String, completion:(resultImage:UIImage) -> Void)
    {

    var imgURL: NSURL = NSURL(string: urlString)!
    let request: NSURLRequest = NSURLRequest(URL: imgURL)
    NSURLConnection.sendAsynchronousRequest(
        request, queue: NSOperationQueue.mainQueue(),
        completionHandler: {(response: NSURLResponse!,data: NSData!,error: NSError!) -> Void in
            if error == nil {
                completion(resultImage: UIImage(data: data))
            }
    })
}
}

//// view controller
class someView: UIViewController {
var image: UIImageView()? //Create the variable the way you need
loadImage(url, completion: { (resultImage) -> Void in
    image = resultImage //Assign the result to the variable
})
 }

I think this will work, if it doesn't, tell me and I'll fix it