Alerts

let alert = UIAlertController(title: "Alert Title", message: "This is an alert message.", preferredStyle: UIAlertControllerStyle.Alert)
// Buttons for the alert
let okButton = UIAlertAction(title: "OK", style: UIAlertActionStyle.Cancel, handler: nil)
// Add button to alert
alert.addAction(okButton)
// Show alert
presentViewController(alert, animated: true, completion: nil)

let alert = UIAlertController(title: "Delete User", message: "Are you sure you want to delete this user?", preferredStyle: UIAlertControllerStyle.Alert)
let cancelButton = UIAlertAction(title: "Cancel", style: UIAlertActionStyle.Cancel, handler: nil)
let deleteButton = UIAlertAction(title: "Delete", style: UIAlertActionStyle.Destructive) { (UIAlertAction) in
    // Delete code here.
}
alert.addAction(cancelButton)
alert.addAction(deleteButton)
presentViewController(alert, animated: true, completion: nil)

(Swift 2.2)