Push Notifications when Timer Expires?

Question

I'm trying to setup push notifications for a timer app in watchOS I'm building, in case a user puts the app into the background. I've already gathered permission from the user in my init, however I'm trying to set up a local notification using UNNotificationRequest. However, when I do set up my UNNotificationRequest, I'm met with the error of Type '()' cannot conform to 'View' when I attempt to add it to my code.

I've tried to add this request to both the NavigationLink area and the second View Controller area, both resulting in me getting the same error, listed above (Type '()' cannot conform to 'View') - what's the alternative in order to enable the notifications?

The code is listed below:

import SwiftUI
import UserNotifications

struct ContentView: View {
    @State var secondScreenShown = false
    @State var timerVal = 60
    var body: some View {
        VStack{
            Picker(selection: $timerVal, label: Text("Set Half Time")) {
                Text("1").tag(60)
                Text("2").tag(120)
                Text("20").tag(1200)
                Text("25").tag(1500)
                Text("30").tag(1800)
                Text("35").tag(2100)
                Text("40").tag(2400)
                Text("45").tag(2700)
                
            }
            NavigationLink(destination: SecondView(secondScreenShown: $secondScreenShown, timerVal: timerVal), isActive: $secondScreenShown) {
                Text("Set Half!")
                ///Trying to enable notifications when the user presses "Set Half"
                let center = UNUserNotificationCenter.current()
                
                let content = UNMutableNotificationContent()
                content.title = "Title"
                content.subtitle = "Subtitle"
                
                let trigger = UNTimeIntervalNotificationTrigger(timeInterval: TimeInterval(timerVal), repeats: false)
                
                let request = UNNotificationRequest(identifier: "Identifier", content: content, trigger: trigger)
                
                UNUserNotificationCenter.current().add(request)
                
            }
        }
    }
}
struct SecondView: View {
    @Binding var secondScreenShown: Bool
    @State var timerVal: Int
    @State var stoppage: Int = 60
    @State var overtime: Bool = false
    
    var body: some View {
            VStack{
                if timerVal > 0 || overtime {
                    Text("Time Remaining in Half")
                        .font(.system(size: 14))
                    HStack(spacing: 33){
                        Text("\(timerVal / 60)")
                            .font(.system(size: 40))
                        Text("\(timerVal % 60)")
                            .font(.system(size: 40))
                            .onAppear(){
                                Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { inv in
                                    if self.timerVal > 0 {
                                        self.timerVal -= 1
                                        if self.timerVal == 0 {
                                            inv.invalidate()
                                        }
                                    }
                                }
                            }
                        
                    }
                    HStack{
                        Text("Minutes")
                            .font(.system(size: 14))
                        Text("seconds")
                            .font(.system(size: 14))
                    }
                    Button(action: {
                        self.secondScreenShown = false
                    }) {
                        Text("Cancel")
                            .foregroundColor(.red)
                    }
    
                } else {
                    
                    VStack{
                        Picker(selection: $stoppage, label: Text("Add Stoppage Time?")) {
                            Text("1").tag(60)
                            Text("2").tag(120)
                            Text("3").tag(180)
                            Text("4").tag(240)
                            Text("5").tag(300)
                            Text("6").tag(360)
                            Text("7").tag(420)
                            Text("8").tag(480)
                            Text("9").tag(540)
                        }
                        Button(action: {
                            self.timerVal = self.stoppage
                            self.overtime = true
                        }) {
                            Text("Add Stoppage")
                                .foregroundColor(.green)
                        }
                        Button(action: {
                            self.secondScreenShown = false
                        }) {
                            Text("Done")
                                .foregroundColor(.red)
                        }
                        
                    }
                    
            }

            }
    }
    
}





struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        Group {
            ContentView()
            ContentView()
        }
    }
}

Answer 1

It is showing error because you have write the add notification code inside the View section.

View is only used for presenting the contents, not writing the actions.

You can write the below code to add the local notification when your navigation is performed.

struct ContentViewNotification: View {

    @State var secondScreenShown = false
    @State var timerVal = 60

    var body: some View {
        
        NavigationView {
         
            VStack{
                Picker(selection: $timerVal, label: Text("Set Half Time")) {
                    Text("1").tag(60)
                    Text("2").tag(120)
                    Text("20").tag(1200)
                    Text("25").tag(1500)
                    Text("30").tag(1800)
                    Text("35").tag(2100)
                    Text("40").tag(2400)
                    Text("45").tag(2700)
                    
                }.onChange(of: timerVal) { val in
                    self.secondScreenShown = true
                }
                
                
                NavigationLink(destination: SecondView(secondScreenShown: $secondScreenShown, timerVal: timerVal), isActive: $secondScreenShown) {
                    Text("Set Half!")
                }.simultaneousGesture(TapGesture().onEnded {
                    
                    //Trying to enable notifications when the user presses "Set Half"

                    let center = UNUserNotificationCenter.current()

                    let content = UNMutableNotificationContent()
                    content.title = "Title"
                    content.subtitle = "Subtitle"

                    let trigger = UNTimeIntervalNotificationTrigger(timeInterval: TimeInterval(timerVal), repeats: false)

                    let request = UNNotificationRequest(identifier: "Identifier", content: content, trigger: trigger)

                    UNUserNotificationCenter.current().add(request)
                })
            }
        }
    }
}