How to Update Text Using Timer in Swiftui

How to update text using timer in SwiftUI

i have managed to update text using alert.

i have declared date as State so whenever date is changed using alert text will also get updated.

struct CurrentDateView : View {
    @State var newDate = Date()

    let timer = Timer.publish(every: 1, on: .current, in: .common).autoconnect()

    var body: some View {
        Text("\(newDate)")
            .onReceive(timer) {
                self.newDate = Date()
            }
    }
}

SwiftUI - Timer to update text

You can try using SwiftUI formatting features vs using String

import SwiftUI
import Combine
struct WorldTimerView: View {
    @StateObject var timers = TimerData()
    //Use TimeZone directly
    @State var timezones: [TimeZone] = [TimeZone.current, TimeZone(identifier: "America/Halifax")!]
        var body: some View {
            List {
                ForEach(timezones, id: \.self) { timeZone in
                    Text(timers.date, formatter: formatter)
                     //Inject the TimeZone to the Text
                    .environment(\.timeZone, timeZone)
                    
                    //You can also use style
                    Text(timers.date, style: .time).environment(\.timeZone, timeZone)
                }
            }
        
        }
    var formatter: DateFormatter{
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "h:mm:ss a"
        return dateFormatter
    }
}

Update Label Text with Timer Values

I see a few issues:

• The finance object goes out of scope when fireTimer() returns. It will be deallocated then. The timer will be setting a label text on a no longer existing view controller.
• Instantiating a UIViewController with FinanceVC() doesn't display it on screen. After instantiating you need to explicitly show. You can do this for example by calling present(_:animated:completion:) from a parent view controller.
• The timer updates dayLabelText which does not update dayLabel.text

Might be good to follow a basic YT tutorial on how to display a view controller.

Good luck, you'll get it soon enough!

SwiftUI update Textlabel from Background Timer

Change your body to.

var body: some View {
    VStack {
        Text("\(timeLeft)")
        
        Button(action: {
            self.start.toggle()
            self.notifyTime = Date().addingTimeInterval(TimeInterval(10)) // add  countdown time in sec
            self.timeLeft = timeDifference(endTime: self.notifyTime)
            self.sendNotification()
            //Timer code - Start your timer
            Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { timer in
                timeLeft -= 1
                
                if timeLeft == 0 {
                    timer.invalidate()
                    //Add your new trigger event
                }
            }
        }) { Text("Start Countdown (10s)")}
        
    }.onAppear(perform: {
        UNUserNotificationCenter.current().requestAuthorization(options: [.badge,.sound,.alert]) { (_, _) in
        }
    })
}

SwiftUI: Updating Model with a timer and reflecting it in UI

I wouldn't rely on a mutating member of the struct to project the changes to the @Published wrapper. I'd use something that explicitly gets/sets the model.

This, for example, works:

struct ContentView: View {
    
    @ObservedObject var viewModel = ViewModel()
    
    var body: some View {
        Text(viewModel.number)
    }
}

class ViewModel: ObservableObject, HeartbeatModifier {
    
    @Published private var model = Model()
    var emitter = HeartbeatEmitter()
    
    init() {
        emitter.delegate = self
    }
    
    func beat() {
        model.number += 1
    }
    
    var number: String {
        "\(model.number)"
    }
}

protocol HeartbeatModifier {
    func beat()
}

protocol Heartbeat {
    var number : Int { get set }
}

struct Model: Heartbeat {
    var number: Int = 0
}

class HeartbeatEmitter {
    
    private var timer: Timer!
    var delegate: HeartbeatModifier?
    
    init() {
        setupTimer()
    }
    
    func setupTimer() {
        timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(notifyDelegate), userInfo: nil, repeats: true)
        RunLoop.main.add(timer, forMode: .common)
    }
    
    @objc
    func notifyDelegate() {
        delegate?.beat()
    }
}

SwiftUI Timer.publish causing whole screen to refresh

If you want to refresh only a part of body, then separate that part into dedicated subview, eg:

struct ApptCardView: View {

    @ObservedObject var apptCardVM: ApptCardViewModel

    var body: some View {
        VStack {
            CurrentDateView()  // << here !!

            Picker("Seizure Type", selection: $apptCardVM.typeIndex) {
            ForEach(0..<apptCardVM.typeChoice.count) {
                Text(self.apptCardVM.typeChoice[$0])
            }
        }.pickerStyle(SegmentedPickerStyle())

        }

    }
}

struct CurrentDateView: View {
    @State private var currentDate = Date()
    let timer = Timer.publish(every: 1, on: .main, in: .common).autoconnect()
    var body: some View {
        Text("\(currentDate)")
            .onReceive(timer) { input in
                self.currentDate = input // << refresh only own body !!
        }
    }
}

---

Related Topics