Swift version: 5.6
UIImageView
is designed to load only local images, but with a little work you can make it load remote images too. To get a basic solution, add an extension to UIImageView
that downloads image data using a GCD background thread, then converts that to a UIImage
, and loads it back into the image view on the main thread:
extension UIImageView {
func load(url: URL) {
DispatchQueue.global().async { [weak self] in
if let data = try? Data(contentsOf: url) {
if let image = UIImage(data: data) {
DispatchQueue.main.async {
self?.image = image
}
}
}
}
}
}
Keep in mind that if you try to call that method several times on the same image view - e.g. if you’re scrolling through a table – then you’re going to hit problems, because multiple images will start downloading.
If you want that to work then you should subclass UIImageView
so you can store the URL that was requested, and compare that URL inside the load()
function to make sure it hasn’t been changed in the time between starting the fetch and loading the image. But if you’re that serious, I would suggest using something like SDWebImage instead: https://github.com/rs/SDWebImage.
SAVE 50% To celebrate WWDC23, all our books and bundles are half price, so you can take your Swift knowledge further without spending big! Get the Swift Power Pack to build your iOS career faster, get the Swift Platform Pack to builds apps for macOS, watchOS, and beyond, or get the Swift Plus Pack to learn advanced design patterns, testing skills, and more.
Available from iOS 8.0
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
Link copied to your pasteboard.