How to Schedule a Same Local Notification in Swift

Swift: how to schedule local notifications with dynamic content

Push notification is best option for your if you want to display weather forecast .

More about this : https://stackoverflow.com/a/41901767/3901620

How do I send local notifications at a specific time in Swift?

This is an example of what I have used for scheduling local notifications using Notification Centre.

let center = UNUserNotificationCenter.current()

let content = UNMutableNotificationContent()
content.title = "My title"
content.body = "Lots of text"
content.sound = UNNotificationSound.default()
content.categoryIdentifier = "yourIdentifier"
content.userInfo = ["example": "information"] // You can retrieve this when displaying notification

// Setup trigger time          
var calendar = Calendar.current
calendar.timeZone = TimeZone.current
let testDate = Date() + 5 // Set this to whatever date you need
let trigger = UNCalendarNotificationTrigger(dateMatching: testDate, repeats: false)

// Create request               
let uniqueID = UUID().uuidString // Keep a record of this if necessary
let request = UNNotificationRequest(identifier: uniqueID, content: content, trigger: trigger)
center.add(request) // Add the notification request

The Date object (represented by testDate above) can be whatever date you want. It is often convenient to create it from DateComponents.

You will need to ask permission for local notifications in the App Delegate at startup to allow this to work. Here is an example.

class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate {

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

        // Ask permission for notifications
        let center = UNUserNotificationCenter.current()
        center.delegate = self
        center.requestAuthorization(options: [.alert, .badge, .sound]) { (granted, error) in
            if granted {
                print("Permission granted")
            } else {
                print("Permission denied\n")
            }
        }
    }
}

How to schedule a same local notification in swift

UILocalNotification has a repeatInterval property that lets you specify how often the notification should repeat. Note that this is an NSCalendarUnit, not just an arbitrary number, so you can only make a notification repeat once per calendar unit (second, minute, hour, day, week, month, etc.). See the NSCalendarUnit documentation for more options.

For example, you can make a notification repeat every month with:

notification.repeatInterval = .CalendarUnitMonth

How to implement scheduled local notification

var dateComponents = DateComponents()
dateComponents.calendar = Calendar.current
dateComponents.hour = 1
let trigger = UNCalendarNotificationTrigger(dateMatching: dateComponents, repeats: true)

This basically takes todays date and sets the time to 1am. Using: UNCalendarNotificationTrigger(dateMatching: you are telling the notification to trigger at 1am today and then repeat at the same time each day.

To trigger a notification based on a time interval you should use the UNTimeIntervalNotificationTrigger.

// Fire in 60 minutes (60 seconds times 60)
let trigger = UNTimeIntervalNotificationTrigger(timeInterval: (60*60), repeats: false)

iOS local notification base on day, time frame and number of times?

If you want to schedule multiple notifications, you need to create multiple notification triggers and register them.

something like:

// Simple extension if you have to create multiple of the same object
extension DateComponents {
   static func triggerFor(hour: Int, minute: Int) -> DateComponents {
      var component = DateComponents()
      component.calendar = Calendar.current
      component.hour = hour
      component.minute = minute
      component.weekday = 1
      return component
   }
}

// Add each trigger into an array with the correct date component
let triggers = [
    UNCalendarNotificationTrigger(dateMatching: DateComponents.triggerFor(hour: 1, minute: 0), repeats: true),
    UNCalendarNotificationTrigger(dateMatching: DateComponents.triggerFor(hour: 2, minute: 0), repeats: true),
    UNCalendarNotificationTrigger(dateMatching: DateComponents.triggerFor(hour: 3, minute: 0), repeats: true),
    UNCalendarNotificationTrigger(dateMatching: DateComponents.triggerFor(hour: 4, minute: 0), repeats: true),
    UNCalendarNotificationTrigger(dateMatching: DateComponents.triggerFor(hour: 5, minute: 0), repeats: true)
]

// Iterate through the array and register the notification with the system
for trigger in triggers {
    // Create the content of the notification
    let content = UNMutableNotificationContent()
    content.title = "My Notification Title"
    content.body = "Body of Notification"

    // Create the request
    let uuidString = UUID().uuidString
    let request = UNNotificationRequest(identifier: uuidString, 
                content: content, trigger: trigger)

    // Schedule the request with the system.
    let notificationCenter = UNUserNotificationCenter.current()
    notificationCenter.add(request) { (error) in
       if error != nil {
          // Handle any errors.
       }
    }
}

Schedule local notification every n days (timezone safe)

You can set them up upfront using UNCalendarNotificationTrigger for an n number of times and using an adjusted calendar for the current timeZone

import SwiftUI

class NotificationManager: NSObject, UNUserNotificationCenterDelegate{
    static let shared: NotificationManager = NotificationManager()
    let notificationCenter = UNUserNotificationCenter.current()
    
    private override init(){
        super.init()
        requestNotification()
        notificationCenter.delegate = self
        getnotifications()
    }
    
    func requestNotification() {
        print(#function)
        notificationCenter.requestAuthorization(options: [.alert, .sound, .badge]) { granted, error in
            
            if let error = error {
                // Handle the error here.
                print(error)
            }
            
            // Enable or disable features based on the authorization.
        }
    }
    /// Uses [.day, .hour, .minute, .second] in current timeZone
    func scheduleCalendarNotification(title: String, body: String, date: Date, repeats: Bool = false, identifier: String) {
        print(#function)
        
        let content = UNMutableNotificationContent()
        content.title = title
        content.body = body
        
        let calendar = NSCalendar.current

        let components = calendar.dateComponents([.day, .hour, .minute, .second], from: date)
        
        let trigger = UNCalendarNotificationTrigger(dateMatching: components, repeats: repeats)
        
        let request = UNNotificationRequest(identifier: identifier, content: content, trigger: trigger)
        notificationCenter.add(request) { (error) in
            if error != nil {
                print(error!)
            }
        }
    }
    ///Sets up multiple calendar notification based on a date
    func recurringNotification(title: String, body: String, date: Date, identifier: String, everyXDays: Int, count: Int){
        print(#function)
        for n in 0..<count{
            print(n)
            let newDate = date.addingTimeInterval(TimeInterval(60*60*24*everyXDays*n))
            //Idenfier must be unique so I added the n
            scheduleCalendarNotification(title: title, body: body, date: newDate, identifier: identifier + n.description)
            print(newDate)
        }
    }
    ///Prints to console schduled notifications
    func getnotifications(){
        notificationCenter.getPendingNotificationRequests { request in
            for req in request{
                if req.trigger is UNCalendarNotificationTrigger{
                    print((req.trigger as! UNCalendarNotificationTrigger).nextTriggerDate()?.description ?? "invalid next trigger date")
                }
            }
        }
    }
    
    func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        
        completionHandler(.banner)
    }
}
class ZuluNotTriggerViewModel:NSObject, ObservableObject, UNUserNotificationCenterDelegate{
    @Published var currentTime: Date = Date()
    let notificationMgr = NotificationManager.shared
    
    
    ///Sets up multiple calendar notification based on a date
    func recurringNotification(title: String, body: String, date: Date, identifier: String, everyXDays: Int, count: Int){
        print(#function)
        notificationMgr.recurringNotification(title: title, body: body, date: date, identifier: identifier, everyXDays: everyXDays, count: count)
        
        //just for show now so you can see the current date in ui
        self.currentTime = Date()
    }
    ///Prints to console schduled notifications
    func getnotifications(){
        notificationMgr.getnotifications()
    }
    
}
struct ZuluNotTriggerView: View {
    @StateObject var vm: ZuluNotTriggerViewModel = ZuluNotTriggerViewModel()
    var body: some View {
        VStack{
            Button(vm.currentTime.description, action: {
                vm.currentTime = Date()
            })
            Button("schedule-notification", action: {
                let twoMinOffset = 120
                //first one will be in 120 seconds
                //gives time to change settings in simulator
                //initial day, hour, minute, second
                let initialDate = Date().addingTimeInterval(TimeInterval(twoMinOffset))
                //relevant components will be day, hour minutes, seconds
                vm.recurringNotification(title: "test", body: "repeat body", date: initialDate, identifier: "test", everyXDays: 2, count: 10)
            })
            
            Button("see notification", action: {
                vm.getnotifications()
            })
        }
    }
}

struct ZuluNotTriggerView_Previews: PreviewProvider {
    static var previews: some View {
        ZuluNotTriggerView()
    }
}

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