Run a background thread on Swift 3

Question

I have a function that goes like this:

fileprivate func setupImageViewWithURL(url: URL) {
    var image: UIImage? = nil
    do {
        try image = UIImage(data         


        

Answer 1

Swift 4.0

func setupImageViewWithURL(url: URL) {

    var image: UIImage? = nil
    DispatchQueue.global(qos: .background).async {
        do {
            try image = UIImage(data: Data(contentsOf: url))!
        } catch {
            print("Failed")
        }
        DispatchQueue.main.async {
            if image != nil {
                image = self.imageWithImage(sourceImage: image!, scaledToWidth: UIScreen.main.bounds.size.width)
                self.imageImageView.image = image
                self.imageImageView.frame = CGRect(x: 0, y: 0, width: UIScreen.main.bounds.size.width, height: (image?.size.height)!)
            }
        }
    }
}