CODEWITHSUNDEEP
swiftuitableviewtimer
Zenman C
Zenman C

Reputation: 1723

How to correct skipping of numbers in a timer countdown in custom cell?

In order to have a consistent implementation of a count down timer (counting down the recording time of audio) in each of my tableView cells, I placed a timer in a custom cell called 'createStoryCell' which is fired when 'countDownTime' is set. 

class CreateStoryCell: UITableViewCell {

weak var delegate: createStoryCellDelegate?
var countDownTimer : Timer?

var countDownTime : Double! {
    didSet {
        startTimer()
    }
}

func startTimer() {

    countDownTimer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { (countDownTimer) in

        if self.countDownTime > 0.0 {
            self.countDown.isHidden = false
            self.countDownTime = self.countDownTime - 1.0
            self.countDown.text = String(self.countDownTime)
        } else {
            countDownTimer.invalidate()
        }
    }
  }
}

To set the countDownTime I use the following code in the 'cellForRowAt' in my viewController. 

if storyItem?.isRecording == false {
            cell.record.setImage(UIImage(named: "smallMicBtn"), for: .normal)
            cell.countDown.isHidden = true
        } else {
            cell.countDownTime = 5.0
            cell.record.setImage(UIImage(named: "recordStop"), for: .normal)
        }

However, when I run the count down timer it skips numbers outputting only 4...2...0. I'd be grateful for any suggestions on how to avoid the skipping of 3 and 1. I have already tried to wrap the 'self.countDown.text = String(self.countDownTime)' in dispatchQueue.main.async but with the same result. Thanks in advance for any pointers.

Upvotes: 0

Views: 83

Answers (1)

Shehata Gamal
Shehata Gamal

Reputation: 100503

This

didSet {
    startTimer()
}

triggers every change of countDownTime here

self.countDownTime = self.countDownTime - 1.0

You shouldn't use didSet , make it a method and call it once from CellForRowAt

Note also cells are dequeeud so after this line inside CellForRowAt do

let cell  = ///
cell.countDownTimer?.invalidate()

in case user scrolls

Upvotes: 4

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