swift invalidate timer in function

Question

I´m trying to create a hockey game clock-app with a main game clock and a start/stop-button. But I´m having trouble with my stopGameclock function. The timer won't invalidate. From searching other questions here I think it has to do with my:

var gameclockTimer = NSTimer()

Seams I can't use this var to invalidate the timer. I know the function works because I can see "stop"

func stopGameclock() {
    self.gameclockTimer.invalidate() 
    print("stop")

Is there any way to make make this function invalidate my timer?

Unfortunately the answers I found so far haven't helped me without the need to put the timer and functions in the ViewController class.

The reason I want to keep the timer in a separate class is because later on I will add several penalty clocks/timers and I want to have them in separate classes to keep it easy to overview.

The complete code looks like this so far:

//  ViewController.swift

import UIKit

class ViewController: UIViewController {

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}

override func viewDidLoad() {
    super.viewDidLoad()
    gameclockLabel.text = "00:00"
}

var startstopPushed: Bool = false

@IBOutlet weak var gameclockLabel: UILabel!
@IBOutlet weak var startstop: UIButton!
@IBAction func startStopbutton(sender: AnyObject) {

    if startstopPushed == false {

        Gameclock().startGameclock()
        startstop.setImage(UIImage(named: "stop.png"), forState: UIControlState.Normal)
        startstopPushed = true
    }
    else
    {
        Gameclock().stopGameclock()
        startstop.setImage(UIImage(named: "start.png"), forState: UIControlState.Normal)
        startstopPushed = false
    }

}

}


class Gameclock : NSObject {

var gameclockTimer = NSTimer()
var timeString: String = ""
var seconds = 0
var minutes = 0

func startGameclock() {

   gameclockTimer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("updateGameclock"), userInfo: nil, repeats: true)

}

func stopGameclock() {
    self.gameclockTimer.invalidate() 
    print("stop")
}

func updateGameclock() {

    seconds += 1

    if seconds == 60 {

        minutes += 1
        seconds = 0

    }

    let secondsString = seconds > 9 ? "\(seconds)" : "0\(seconds)"
    let minutesString = minutes > 9 ? "\(minutes)" : "0\(minutes)"


    timeString = "\(minutesString):\(secondsString)"
    print(timeString)

}
}

Answer 1

the problem is that each time you're accessing GameClock, you are creating a new instance of it - so the instance that you're stopping is not the one that you created.

You can keep all of the functionality in the GameClock class, but you will need to define a variable in ViewController to access it.

class ViewController: UIViewController {
    var gameClock = Gameclock()

and then in your startstopPushed method make these changes

    if startstopPushed == false {

        //Gameclock().startGameclock()
        gameClock.startGameclock()
        startstop.setImage(UIImage(named: "stop.png"), forState: UIControlState.Normal)
        startstopPushed = true
    }
    else
    {
        //Gameclock().stopGameclock()
        gameClock.stopGameclock()
        startstop.setImage(UIImage(named: "start.png"), forState: UIControlState.Normal)
        startstopPushed = false
    }

Answer 2

I think this should work:

I create a var gameClock just once which represents your game clock class and then run the methods on this one class

override func viewDidLoad() {
    super.viewDidLoad()
    gameclockLabel.text = "00:00"
}

var startstopPushed: Bool = false
var gameClock = GameClock()

@IBOutlet weak var gameclockLabel: UILabel!
@IBOutlet weak var startstop: UIButton!
@IBAction func startStopbutton(sender: AnyObject) {

    if startstopPushed == false {

        gameClock.startGameclock()
        startstop.setImage(UIImage(named: "stop.png"), forState: UIControlState.Normal)
        startstopPushed = true
    }
    else
    {
        gameClock.stopGameclock()
        startstop.setImage(UIImage(named: "start.png"), forState: UIControlState.Normal)
        startstopPushed = false
    }

}