Created
December 18, 2019 23:28
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Playground usado no vídeo DispatchGroups! Caso o arquivo não abra diretamente do xcode (apple sendo apple haha) copie o conteúdo e cole em um playground seu! :D
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import UIKit | |
import PlaygroundSupport | |
/* | |
DispatchGroups: Monitora um grupo de tasks como uma unidade. Com isso ele consegue executar uma ação (sync ou async) após o término de todas as tasks. | |
*/ | |
PlaygroundPage.current.needsIndefiniteExecution = true | |
//FORMA SYNC | |
// | |
//let group = DispatchGroup() | |
//let queue = DispatchQueue.global(qos: .userInitiated) | |
// | |
//queue.async(group: group) { | |
// print("Start job 1") | |
// Thread.sleep(until: Date().addingTimeInterval(5)) | |
// print("End job 1") | |
//} | |
// | |
//queue.async(group: group) { | |
// print("Start job 2") | |
// Thread.sleep(until: Date().addingTimeInterval(1)) | |
// print("End job 2") | |
//} | |
// | |
//if group.wait(timeout: .now() + 6) == .timedOut { | |
// print("xiiii") | |
//}else{ | |
// print("deu bom!") | |
//} | |
//FORMA ASYNC | |
// | |
let group = DispatchGroup() | |
let queue = DispatchQueue.global(qos: .userInteractive) | |
let semaphore = DispatchSemaphore(value: 5) | |
let base = "https://wolverine.raywenderlich.com/books/con/image-from-rawpixel-id-" | |
let ids = [466881, 466910, 466925, 466931, 466978, 467028, 467032, 467042, 467052] | |
var images: [UIImage] = [] | |
for id in ids { | |
guard let url = URL(string: "\(base)\(id)-jpeg.jpg") else { continue } | |
semaphore.wait() | |
group.enter() | |
let task = URLSession.shared.dataTask(with: url) { data,_,error in | |
defer { | |
group.leave() | |
semaphore.signal() | |
} | |
sleep(1) | |
if error == nil, | |
let data = data, | |
let image = UIImage(data: data) { | |
images.append(image) | |
} | |
} | |
task.resume() | |
} | |
group.notify(queue: queue) { | |
print("terminou!") | |
PlaygroundPage.current.finishExecution() | |
} |
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