iOS Concurrency with GCD & Operations
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Next episode: 06. The Right Way to Download Images
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Challenge: A Better Way to Download Images
In the first episode, I showed you the sample app for this course. It’s unresponsive to user interaction because the image downloads all happen on the main thread, which should only be used for user interface tasks.
[weak self] in
guard let self else { return }
store.downloadImageOffMainQueue(index: image.id) // change On to Off
DispatchQueue.global(qos: .utility).async {
}
DispatchQueue.global(qos: .utility).async { [weak self] in
guard let self else { return }
}
if let data = try? Data(contentsOf: self.images[index].url),
let decodedImage = UIImage(data: data) {
images[index].image = decodedImage
}
DispatchQueue.main.async {
self.images[index].image = decodedImage
}