timer that works in the background Swift 5 [duplicate] - ios

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update label from background timer
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iOS Swift Timer in not firing if the App is in the background
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Closed 3 years ago.
I'd like to create a simple timer app that works the same way of the native timer of iOS.
To start I just write some simple code that print the second starting to 0 to infinite.
The first problem was that if you go to the home screen, the task obviously stops to work
so I easily sorted just checking the box into background mode - Audio Airplay, and Picture in Picture (inside project - targets - Signing and Capabilities)
now my task works fine.. even in the background.. unless you put your app into a real device
in this case when you go into the background it doesn't work
after that I searched online for a solution and what I've learnt that Apple does't allow the apps to work into the background as you pleased and after 180 seconds the system just "kill" the background task. I just wonder how all the timer app in the Appstore works..
An Interesting thing that I've come across was when I watched an Apple developer conference that they talk about this new framework of background that you basically can make your app working in the background for heavy tasks when the iPhone is charging, and not only that you can forecast when the user will use your app and have some background tasks that work in the background in order to prepare the app to be updated. The link is this https://developer.apple.com/videos/play/wwdc2019/707/
after this I've tried different approaches to sort my problem but nothing has worked yet.. I have followed this tutorial which I found interesting https://medium.com/over-engineering/a-background-repeating-timer-in-swift-412cecfd2ef9 but it didn't work for me (maybe because of the version of swift outdated or simply because of me) if you guys have managed to make the timer work in the background in your real device let me know.. I would like to understand it well rather than copy and paste the code.
Happy coding to all
the tutorial code:
class RepeatingTimer {
let timeInterval: TimeInterval
init(timeInterval: TimeInterval) {
self.timeInterval = timeInterval
}
private lazy var timer: DispatchSourceTimer = {
let t = DispatchSource.makeTimerSource()
t.schedule(deadline: .now() + self.timeInterval, repeating: self.timeInterval)
t.setEventHandler(handler: { [weak self] in
self?.eventHandler?()
})
return t
}()
var eventHandler: (() -> Void)?
private enum State {
case suspended
case resumed
}
private var state: State = .suspended
deinit {
timer.setEventHandler {}
timer.cancel()
/*
If the timer is suspended, calling cancel without resuming
triggers a crash. This is documented here https://forums.developer.apple.com/thread/15902
*/
resume()
eventHandler = nil
}
func resume() {
if state == .resumed {
return
}
state = .resumed
timer.resume()
}
func suspend() {
if state == .suspended {
return
}
state = .suspended
timer.suspend()
}
}