Timers

In this example when startTimer function is called it creates a timer that fires every second repeatedly. Every time the timer fires it makes a call to the notifyUiToUpdate function.

class Timer {
    
    private var _timer: NSTimer!

    func startTimer() {
        _timer = NSTimer.scheduledTimerWithTimeInterval(1.0, target: self, 
            selector: #selector(notifyUiToUpdate), userInfo: nil, repeats: true)
    }
    
    func stopTimer() {
        _timer.invalidate()
    }
    
    @objc func notifyUiToUpdate() {
        NSNotificationCenter.defaultCenter().postNotification(
            NSNotification(name: "updateView", object: nil))
    }
}

(Swift 2.2)