stoping timer on viewcontroller dismiss swift

Question

I have a timer in a view controller which I use to check a function. How ever, If I dismiss the Viewcontroller where the timer is set, it still continues or if the time reaches zero, I want to automatically dismiss the viewcontroller. In my case now, if I dismiss the viewcontroller manually without the viewcontroller reaching zero, the time still continues till the counter reaches ero.

how can I set my code such that if I dismiss the Viewcontroller myself, the time stops and not reach zero so that the condition I put if the time is zero does not run.

below is my code

override func viewDidLoad() {
        super.viewDidLoad()

        var _ = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(updateCounter), userInfo: nil, repeats: true)

        timerLabel.text = "\(counter)"
    }


    @objc func updateCounter() {
        //you code, this is an example
        if counter >= 0 {
            timerLabel.text = "\(counter)"
            counter -= 1
        }

        if counter == 0 {

            Print.HOMEPRINT("COUNTER GOT TO ZERO")

            dismiss(animated: true, completion: nil)
        }
    }

Answer 1

declare a public variable for timer and then invalidate it when you want to stop.

var timer : Timer?

override func viewDidLoad() {
    super.viewDidLoad()

    timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(updateCounter), userInfo: nil, repeats: true)

    timerLabel.text = "\(counter)"
}


@objc func updateCounter() {
    //you code, this is an example
    if counter >= 0 {
        timerLabel.text = "\(counter)"
        counter -= 1
    }

    if counter == 0 {
        timer?.invalidate()
        Print.HOMEPRINT("COUNTER GOT TO ZERO")

        dismiss(animated: true, completion: nil)
    }
}

Answer 2

Create a global variable for Timer

var myTimer : Timer?

override func viewDidLoad() {
    super.viewDidLoad()

    myTimer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(updateCounter), userInfo: nil, repeats: true)

    timerLabel.text = "\(counter)"
}


@objc func updateCounter() {
    //you code, this is an example
    if counter >= 0 {
        timerLabel.text = "\(counter)"
        counter -= 1
    }

    if counter == 0 {
        if (myTimer != nil)
        {
          myTimer?.invalidate()
          myTimer = nil
        }
        Print.HOMEPRINT("COUNTER GOT TO ZERO")

        dismiss(animated: true, completion: nil)
    }
}

//MARK: Manually dismiss controller

    @objc func dismissButtonTapped()
    {
    if (myTimer != nil)
            {
              myTimer?.invalidate()
              myTimer = nil
            }
    dismiss(animated: true, completion: nil)
    }