How to programmatically dismiss UIAlertController without any buttons?

for swift you can do:

nameOfYourAlertController.dismiss(animated: true, completion: nil)

true will animate the disappearance, and false will abruptly remove the alert

Use the alertController's own method to destroy itself.

UIAlertController *alertController = [UIAlertController 
alertControllerWithTitle:...];

[alertController dismissViewControllerAnimated:YES completion:nil];

If you want to post an alert that displays briefly, then dismisses itself, you could use the following method:

  func postAlert(title: String, message: String) {
    let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
    self.present(alert, animated: true, completion: nil)

    // delays execution of code to dismiss
    DispatchQueue.main.asyncAfter(deadline: .now() + 2.0, execute: {
      alert.dismiss(animated: true, completion: nil)
    })
  }

Generally the parent view controller is responsible for dismissing the modally presented view controller (your popup). In Objective-C you would do something like this in the parent view controller:

[self dismissViewControllerAnimated:YES completion:nil];

The same code in Swift versions < 3 would be:

self.dismissViewControllerAnimated(true, completion: nil)

Swift 3.0:

self.dismiss(animated: true, completion: nil)