swift timer invalidation inside tableView cell

Question

I'm a beginner just start learning swift for a few months now. Please help me with a timer invalidation issue. Feel free to make me feel stupid :). I know it's a bit messy and I'm willing to take pointer on how to do it better next time.

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "CustomCell", for: indexPath) as! CustomCustomerCell
    let appDelegate = UIApplication.shared.delegate as! AppDelegate

    let object = appDelegate.Queuelist[indexPath.row]

    if let genderInital = object.gender?.characters.first {
        cell.genderlabel.text = " \(genderInital)"
    }
    object.timerStarted()


    cell.waitedTimeLabel.text = "\(object.counter)"

    cell.nameLabel.text = object.name
    cell.languageLabel.text = object.language
    cell.reasonLabel.text = object.reasonOfVisit
    return cell
}

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {

    var customerName: String?


    if let indexPathForName = tableView.indexPathForSelectedRow {

        let appDelegate = UIApplication.shared.delegate as! AppDelegate
        let selectedCustomer = appDelegate.Queuelist[indexPathForName.row]
        customerName = selectedCustomer.name
        }


    let alertController = UIAlertController(title: customerName, message: "message", preferredStyle: .alert)

    let cancelAction = UIAlertAction(title: "cancel", style: .cancel, handler: nil)

    let editAction = UIAlertAction(title: "edit", style: .default) {action -> Void in

        self.performSegue(withIdentifier: "addSegue", sender: alertController)
        }
    let takeCustomerAction = UIAlertAction(title: "take customer", style: .default) {
        action -> Void in
        if let indexpath = tableView.indexPathForSelectedRow {
            let appDelegate = UIApplication.shared.delegate as! AppDelegate

            let object = appDelegate.Queuelist[indexpath.row]
            object.timer?.invalidate()
            appDelegate.Queuelist.remove(at: indexpath.row)
            appDelegate.storedQueuelist()
            tableView.deleteRows(at: [indexPath], with: .fade)
        }
    }

    alertController.addAction(takeCustomerAction)
    alertController.addAction(editAction)
    alertController.addAction(cancelAction)
    self.present(alertController, animated: true, completion: nil)
}

Answer 1

If you are assigning timer for each cell. You just need to declare method startTimer() and endTimer() on CustomCustomerCell class.

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell{
    let cell = tableView.dequeueReusableCell(withIdentifier: "CustomCell", for: indexPath) as! CustomCustomerCell
    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let object = appDelegate.Queuelist[indexPath.row]

    if let genderInital = object.gender?.characters.first {
        cell.genderlabel.text = " \(genderInital)"
    }
    cell.startTimer()

    cell.waitedTimeLabel.text = "\(object.counter)"
    cell.nameLabel.text = object.name
    cell.languageLabel.text = object.language
    cell.reasonLabel.text = object.reasonOfVisit

    return cell
  }

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
//Use below method if you want to end timer for all cells
        //endTimerForAllCells(tableView)
    var customerName: String?
    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let selectedCustomer = appDelegate.Queuelist[indexPath.row]
    customerName = selectedCustomer.name

    let alertController = UIAlertController(title: customerName, message: "message", preferredStyle: .alert)

    let cancelAction = UIAlertAction(title: "cancel", style: .cancel, handler: nil)

    let editAction = UIAlertAction(title: "edit", style: .default) {action -> Void in
    self.performSegue(withIdentifier: "addSegue", sender: alertController)
    }

    let takeCustomerAction = UIAlertAction(title: "take customer", style: .default) {
    action -> Void in

    if let indexpath = tableView.indexPathForSelectedRow {
        let appDelegate = UIApplication.shared.delegate as! AppDelegate

        if let cell = tableView.cellForRowAtIndexPath(indexPath) as? CustomCustomerCell{
        cell.endTimer()
        }
        appDelegate.Queuelist.remove(at: indexpath.row)
        appDelegate.storedQueuelist()
        tableView.deleteRows(at: [indexPath], with: .fade)
      }
   }

    alertController.addAction(takeCustomerAction)
    alertController.addAction(editAction)
    alertController.addAction(cancelAction)
    self.present(alertController, animated: true, completion: nil)
  }

//Below method is use to end timer of all cells
func endTimerForAllCells(tableView:UITableView){
    let appDelegate = UIApplication.shared.delegate as! AppDelegate
     let totalRows = appDelegate.Queuelist
     if totalRows.count != 0{
        for row in 0...totalRows.count - 1{
            let index = NSIndexPath(forRow: row, inSection: 0)
            if let cell = tableView.cellForRowAtIndexPath(index) as? CustomCustomerCell{
                cell.endTimer()
              }
            }
          }
        }
      }

Declaring method for timer in CustomCustomerCell class.

private var timer: Timer?
func startTimer(){

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

func endTimer() {
    timer?.invalidate
    timer = nil
}

func methodToDoSomethingAtEachInterval(){
 //Do something at each time interval for each tableviewCell
}