repeated alarm notifications in swiftui - xcode

Question

I have created a piece of code to send a local notification at 3 pm and the user can toggle it with a toggle switch. I used an AppStorage wrapper to remember the state it was in. The code works until I toggle the switch on and off (simulating whether the user switches it multiple times) and the number of times I switched the toggle, that same number comes as a notification (i.e. I toggle 5 times, I get 5 notifications all at once). this is the code
struct trial: View {
#AppStorage("3") var three = false
func firstNotify() {
let content = UNMutableNotificationContent()
content.title = "It is 3pm"
content.subtitle = "Read the Prime Hour"
content.sound = UNNotificationSound(named: UNNotificationSoundName(rawValue: "notifysound.wav"))
// content.sound = UNNotificationSound(named: UNNotificationSoundName(rawValue: "notifysound"))
var dateComponents = DateComponents()
dateComponents.hour = 15
dateComponents.minute = 00
dateComponents.second = 00
let trigger = UNCalendarNotificationTrigger(dateMatching: dateComponents, repeats: true)
// choose a random identifier
let request = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: trigger)
// add our notification request
UNUserNotificationCenter.current().add(request)
UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .badge, .sound]) { success, error in
if success {
print("All set!")
} else if let error = error {
print(error.localizedDescription)
}
}
}
#State private var name: String = "Tim"
var body: some View {
VStack {
Toggle(isOn: $three) {
Text("3 pm")
}
.padding(.horizontal)
.onChange(of: three) { newValue in
if newValue {
firstNotify()
}
}
}
}
}
struct trial_Previews: PreviewProvider {
static var previews: some View {
trial()
}
}
I think what's happening is that the func is not reading whether the toggle is on or off but just adds a notification each time the switch gets turned on. Would anyone know the solution to this???

Answer 1

The toggle is really only scheduling a new notification on every change of the value to true.
This piece of code means that a new notification will be scheduled each time this method is called.
// choose a random identifier
let request = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: trigger)
// add our notification request
UNUserNotificationCenter.current().add(request)
Not entirely sure what the desired logic is, but you could solve this by either updating the existing notification or clearing out the old one and adding a new one. Rather than creating a new UUID for each notification, it may be best to have an ID convention or otherwise store it so it can be accessed or removed.
You could store the rather than the toggle value:
#AppStorage("notification_id") var notificationID = nil // I don't know if this can be a string or nil, but hopefully it leads you in the right direction.
// Then when creating the request.
let id = notificationID ?? UUID().uuidString
let request = UNNotificationRequest(identifier: id, content: content, trigger: trigger)
notificationID = id
And there needs to be another method when to unschedule when they toggle the other direction. You could simply check to see if the id exists.
if let id = notificationID {
UNUserNotificationCenter.current().removePendingNotificationRequests(withIdentifiers identifiers: [id])
// OR
UNUserNotificationCenter.current()removeAllPendingNotificationRequests()
}