App is running in background about srcountdowntimer HOT 6 CLOSED

override func viewDidLoad() {
    super.viewDidLoad()
    NotificationCenter.default.addObserver(self, selector: #selector(willResignActive), name: .UIApplicationWillResignActive, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(didBecomeActive), name: .UIApplicationDidBecomeActive, object: nil)
}

@objc func willResignActive(_ notification: Notification) {
     currentBackgroundDate = Date()
     timer.invalidate()
}
    
@objc func didBecomeActive(_ notification: Notification) {
     let calender: Calendar = Calendar.current
     let components: DateComponents = calender.dateComponents([.year, .month, .day, .hour, .minute, .second], from: currentBackgroundDate!, to: Date())
     let seconds = components.second
     let secondsUpdate = countDownView.currentSecond - seconds!
        
     countDownView.start(beginingValue: secondsUpdate, interval: 1)
}