Timer Updating Label 1 Second Behind 2nd Timer Counting Down - ios

Question

I'm having difficulties attempting to link two timers together. I'm trying to have a timer count down from a specified amount and to have a second timer constantly updating a label on a view controller. However, I end up having the timer that updates the label lagging exactly 1 second behind the first timer in the timer class. Here's what I have for the view controller: (note that this is a condensed version of my code)
class HomeViewController: UIViewController {
#IBOutlet var timeLabel: UILabel!
override func viewDidLoad() {
timeLabel.text = account.deedManager.globalTimer.timerStr
Timer.scheduledTimer(timeInterval: 0.05, target: self, selector: #selector(UpdateTime), userInfo: nil, repeats: true)
}
#objc func UpdateTime() {
self.timeLabel.text = account.deedManager.globalTimer.timerStr
}
}
And here is the Timer class:
class TimerModel: NSObject, NSCoding {
var myTimer: Timer? = Timer()
var timerInterval: TimeInterval = 1.0
var timerEnd: TimeInterval = 0.0
var timerCount: TimeInterval = 86400.0 // 24 hours
var timerStr: String = "TIME"
func StartTimer(time: Double) {
timerCount = time
myTimer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(UpdateTime), userInfo: nil, repeats: true)
}
#objc func UpdateTime() {
self.timerStr = self.TimerDate(time: self.timerCount)
self.timerCount-=1
print(self.timerStr)
}
func TimerDate(time:TimeInterval) -> String {
let hours = Int(time) / 3600
let minutes = Int(time) / 60 % 60
let seconds = Int(time) % 60
return String(format: "%02i:%02i:%02i", hours, minutes, seconds)
}
}
I've tried to make the first timer a 0.05 interval so that it updates more rapidly than the timer class, but it lags behind exactly a second no matter what interval I put it at. I don't want to put the count down timer inside the view controller as I want the timer global for all view controllers. If you have any ideas, let me know.

Answer 1

First you need to switch the order around so that you are setting the text after you decrement the timerCount:
#objc func UpdateTime() {
self.timerCount-=1
self.timerStr = self.TimerDate(time: self.timerCount)
print(self.timerStr)
}
Then, you can delete the 0.05-second timer because as you said, that doesn't seem to work.
Try using the delegate pattern instead.
protocol TimerModelDelegate {
func timerTextDidChange(_ timer: TimerModel, text: String)
}
And then in TimerModel,
weak var delegate: TimerModelDelegate?
var timerStr: String = "TIME" {
didSet {
delegate?.timerTextDidChange(self, text: timerStr)
}
}
In HomeViewController, do this:
class HomeViewController: UIViewController, TimerModelDelegate {
#IBOutlet var timeLabel: UILabel!
override func viewDidLoad() {
timeLabel.text = account.deedManager.globalTimer.timerStr
account.deedManager.globalTimer.delegate = self
account.deedManager.globalTimer.StartTimer(time: 60)
}
// You don't need the UpdateTime method here
func timerTextDidChange(_ timer: TimerModel, text: String) {
timeLabel.text = text
}
}

Answer 2

You have this function:
#objc func UpdateTime() {
self.timerStr = self.TimerDate(time: self.timerCount)
self.timerCount-=1
print(self.timerStr)
}
Replace it with
#objc func UpdateTime() {
self.timerCount-=1
self.timerStr = self.TimerDate(time: self.timerCount)
print(self.timerStr)
}
Explanation:
You first have to change the value, then display it
Notice the first two lines are swapped. This should fix your issue.