倒计时的多个计时器无法正常工作 | SwiftUI

Question

I have an auction app running. I need several timers counting down in the UI, these timers have different end Dates, and the end seconds can be updated when SignalR receives a new value.

I have implemented running timers in my current solution, but sometimes and suddenly, they start having delays between counting down a second.

The timers are inside these components called LotCard within the ForEach

ForEach($lotService.getLotListDto) { $item in
    LotCard(lotCardViewModel: $item.lotCardViewModel,
            lotDto: item,
            fnStartLotConnection: { value in lotService.initSingleLotCard(uID: value)})

}

This is the necessary code within these components:

//MARK: Timer
@State var timeRemaining = 9999
let timerLotCard = Timer.publish(every: 1, on: .main, in: .common).autoconnect()

HStack(spacing: 3){
    Image(systemName: "stopwatch")
    if(lotCardViewModel.showTimer){
        Text("\(timeRemaining.toTimeString())")
            .font(.subheadline)
            .onReceive(timerLotCard){ _ in
                if self.timeRemaining > 0 {
                    self.timeRemaining -= 1
                    
                    if(self.timeRemaining <= 0){
                        self.timerLotCard.upstream.connect().cancel()
                    }
                }else{
                    self.timerLotCard.upstream.connect().cancel()
                }
            }
    }
}

I guess it's a problem with threads and using many timers simultaneously with the same Instance but I am not an experienced developer using SwiftUI / Swift .

This is how my interface looks like:

Thanks for your help.

Answer 1

I came up with this approach thanks to the comments in my question. I hope it works and suits your problems.

First, I created a Published Timer , meaning every component will run the same Timer.

import Foundation
import Combine

class UIService : ObservableObject {
    
    static let shared = UIService()

    //MARK: Timer to be used for any interested party
    @Published var generalTimer = Timer.publish(every: 1, on: .main, in: .common).autoconnect()

}

Finally, I am using that Timer wherever I want to use it. In this case, I use it in every LotCard component.

struct LotCard: View {

//MARK: Observable Class
@EnvironmentObject var UISettings: UIService

//MARK: Time for the counting down
@State var timeRemaining = 9999

var body: some View {
    HStack{
        
        Text(timeRemaining.toTimeString())
            .onReceive(UISettings.generalTimer){ _ in
                if self.timeRemaining > 0 {
                    self.timeRemaining -= 1
                }
            }
    }
}
}