@IBAction func button(_ sender: UIButton) {
acrivityIndicator.startAnimating()
//Код со множественными обращениями к серверу (URLSession.shared.dataTask)
acrivityIndicator.stopAnimating()
}DispatchQueue.main.async {
self.acrivityIndicator.startAnimating()
}@IBAction func button(_ sender: UIButton) {
DispatchQueue.global().async {
DispatchQueue.main.async {
acrivityIndicator.startAnimating()
}
//Код со множественными обращениями к серверу (URLSession.shared.dataTask)
DispatchQueue.main.async {
acrivityIndicator.stopAnimating()
}
}
}print(Thread.isMainThread)
print(Thread.current)true
<NSThread: 0x60000203e280>{number = 1, name = main}
class ViewController: UIViewController {
@IBOutlet var button: UIButton!
var alert: UIAlertController?
func displayActivityIndicatorAlert() {
alert = UIAlertController(title: "Deleting from black list...", message: nil, preferredStyle: .alert)
let activityIndicator = UIActivityIndicatorView(style: .medium)
activityIndicator.translatesAutoresizingMaskIntoConstraints = false
activityIndicator.isUserInteractionEnabled = false
activityIndicator.startAnimating()
alert!.view.addSubview(activityIndicator)
alert!.view.heightAnchor.constraint(equalToConstant: 95).isActive = true
activityIndicator.centerXAnchor.constraint(equalTo: alert!.view.centerXAnchor, constant: 0).isActive = true
activityIndicator.bottomAnchor.constraint(equalTo: alert!.view.bottomAnchor, constant: -20).isActive = true
present(alert!, animated: true)
}
func dismissActivityIndicatorAlert() {
alert?.dismiss(animated: true)
alert = nil
}
var blackList = [Int](0...9)
let lock = NSLock()
func asyncDeleteBlackList() {
var tasks = [URLSessionTask]()
tasks.reserveCapacity(10)
var results = [Int: String]()
results.reserveCapacity(10)
let group = DispatchGroup()
displayActivityIndicatorAlert()
for item in blackList {
group.enter()
let url = URL(string: "https://.../api/v1/today/batch")!
let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
if let error = error {
// Что-то делаем с ошибкой на клиенте...
return
}
guard let httpResponse = response as? HTTPURLResponse,
(200...299).contains(httpResponse.statusCode) else
{
// Что-то делаем с ошибкой на сервере...
return
}
if let mimeType = httpResponse.mimeType,
mimeType == "application/json",
let data = data,
let string = String(data: data, encoding: .utf8)
{
print("Запрос №\(item) завершён.")
self.lock.lock()
results[item] = string
self.lock.unlock()
group.leave()
}
}
tasks.append(task)
task.resume()
}
group.notify(queue: .main) {
print("\nЗадача завершена.")
self.dismissActivityIndicatorAlert()
}
}
override func viewDidLoad() {
button.addTarget(self, action: #selector(pressed(sender:)), for: .touchUpInside)
}
@objc
func pressed(sender: UIButton) {
asyncDeleteBlackList()
}
}
