iOS: load an image from url

Question

I need to load an image from a url and set it inside an UIImageView; the problem is that I don\'t know the exact size of the image, then how can I show the image correctly?<

Answer 1

In swift:

var url = NSURL.URLWithString("http://www.example.com/picture.png")
var data = NSData(contentsOfURL : url)
var image = UIImage(data : data)
image.size // if you need it

Answer 2

SWIFT 5.0 + fetch on background

private func fetchImage(_ photoURL: URL?) {

    guard let imageURL = photoURL else { return  }

    DispatchQueue.global(qos: .userInitiated).async {
        do{
            let imageData: Data = try Data(contentsOf: imageURL)

            DispatchQueue.main.async {
                let image = UIImage(data: imageData)
                self.userImageView.image = image
                self.userImageView.sizeToFit()
                self.tableView.reloadData()
            }
        }catch{
            print("Unable to load data: \(error)")
        }
    }
}

Answer 3

If you prefer you can even move it to an UIImage extension:

extension UIImage {
    
    //NOTE: This is not thread safe, please run it on a background thread.
    convenience init?(fromFile filePath:String) {
        guard let url = URL(string: filePath) else {
            return nil
        }
        
        self.init(fromURL: url)
    }
    
    //NOTE: This is not thread safe, please run it on a background thread.
    convenience init?(fromURL url:URL) {
        let imageData: Data
        
        do {
            imageData = try Data(contentsOf: url)
        } catch {
            return nil
        }
        
        self.init(data: imageData)
    }
    
}