Check if countdown has reached zero and update UILabel - ios

Question

I have a UILabel which displays my current 24 hour countdown. I would like to check if the countdown is at zero and when it is to update my UILabel. The way it is set up now if it is reached 24 hours it keeps running as negative numbers. For example -1h-55m-54s
I have tried to check if UILabel contains "-" and also if the value is less than 0 however have not got it to work.
func timeLeftExtended(date:Date) ->NSAttributedString{
let cal = Calendar.current
let now = Date()
let calendarUnits:NSCalendar.Unit = [NSCalendar.Unit.hour, NSCalendar.Unit.minute, NSCalendar.Unit.second]
let components = (cal as NSCalendar).components(calendarUnits, from: now, to: date, options: [])
let fullCountDownStr = "\(components.hour!.description)h " + "\(components.minute!.description)m " + "\(components.second!.description)s "
let mutableStr = NSMutableAttributedString(string: fullCountDownStr, attributes: [NSAttributedString.Key.foregroundColor:UIColor.white])
for (index, char) in mutableStr.string.enumerated()
{
if(char == "h" || char == "m" || char == "s")
{
mutableStr.removeAttribute(NSAttributedString.Key.foregroundColor, range: NSMakeRange(index, 1))
mutableStr.addAttributes([NSAttributedString.Key.foregroundColor : UIColor.lightGray], range: NSMakeRange(index, 1))
}
}
return mutableStr
}
func updateCountDown() {
if let waitingDate = UserDefaults.standard.value(forKey: "waitingDate") as? Date {
if let waitingDate = UserDefaults.standard.object(forKey: "waitingDate") as? Date,
waitingDate < Date() {
self.timeLabel.text = "Time ran out"
print("It is time for you to check in")
}
// if self.timeLeftExtended(date: waitingDate) <= 0{
//change label
}
self.timeLabel.attributedText = self.timeLeftExtended(date: waitingDate)
} else {
let newDate = Calendar.current.date(byAdding: .hour, value: 24, to: Date())
UserDefaults.standard.set(newDate, forKey: "waitingDate")
self.timeLabel.attributedText = self.timeLeftExtended(date: newDate!)
}
}

Answer 1

Just compare the dates
if let waitingDate = UserDefaults.standard.object(forKey: "waitingDate") as? Date,
waitingDate < Date() {
// waitingDate exists and is earlier than the current date
}
And you can create the countdown string much shorter
let components = cal.dateComponents([.hour, .minute, .second], from: now, to: date)
let fullCountDownStr = "\(components.hour!)h \(components.minute!)m \(components.second!)s "

Answer 2

Here is how I use UILabel to display count down timer
First, these are my variables
#IBOutlet weak var lblCountDownTime: UILabel! //label to display count down
var countDownTimer: Timer? // timer to count down
Second, this is how I display count down, hope it help
self.countDownTimer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(self.countDownTime), userInfo: nil, repeats: true);
func countDownTime() {
let now = Date();
let calendar = Calendar.current;
let comps = calendar.dateComponents(Set<Calendar.Component>([.minute, .second]), from: now, to: self.startTime);
var strMinute = "\(comps.minute!)";
var strSecond = "\(comps.second!)";
if (comps.minute! < 10) {
strMinute = "0\(comps.minute!)";
}
if (comps.second! < 10) {
strSecond = "0\(comps.second!)";
}
if (comps.minute! <= 0 && comps.second! <= 0) {
self.countDownTimer?.invalidate();
}
else {
self.lblCountDownTime.text = "\(strMinute):\(strSecond)\"";
}
}