swift - Countdown in UIAlertController -

i countdown 3 seconds in alert controller. not sure how this. can alert disappear in 3 seconds, countdown missing.

//simple alert dialog let alertcontroller = uialertcontroller(title: "workflow successful", message: "modified reminder's priority or list.", preferredstyle: .alert)  var secs = 3 let defaultaction = uialertaction(title: "dismiss in " + secs, style: .default, handler: nil) alertcontroller.addaction(defaultaction)  dispatch_async(dispatch_get_main_queue()) {     //self.presentviewcontroller(alertcontroller, animated: true, completion: nil)     self.showviewcontroller(alertcontroller, sender: self) }  let delaytime = dispatch_time(dispatch_time_now,               int64(secs * double(nsec_per_sec))) dispatch_after(delaytime, dispatch_get_main_queue()) {     alertcontroller.dismissviewcontrolleranimated(true, completion: nil) } 

after set delay time dismiss view controller, can set timer call function after second like:

var timer = nstimer.scheduledtimerwithtimeinterval(1.0, target: self, selector: #selector(self.decrease), userinfo: nil, repeats: true)  func decrease() {     self.secs-=1     self.defaultaction.setvalue("dismiss in \(self.secs)", forkey: "title") } 

and update title new time.