Local Notifications

Working with Local Notifications and the UserNotifications framework.

1. Requesting Permissions to use Notifications

Check for authorization status

UNUserNotificationCenter.current().getNotificationSettings { (settings) in
  if settings.authorizationStatus == .authorized {
    //
  } else {
    self.requestNotificationPermissions()
  }
}

Request authorization

let center = UNUserNotificationCenter.current()
center.requestAuthorization(options: [.alert, .sound]) { (granted, error) in
  if let error = error {
    // error encountered
    print("error encountered: \(error)")
    return
  }
  if granted {
    print("access granted")
  } else {
    print("access denied")
  }
}

2. Create the Notification's content

let content = UNMutableNotificationContent()
content.title = "Code Alert"
content.body = "Starting the day with code"

3. Create the trigger

let timeInterval = Date().timeIntervalSinceNow + 5
let trigger = UNTimeIntervalNotificationTrigger(timeInterval: timeInterval, repeats: false)

Types of Local Notification Triggers

1. UNCalendarNofificationTrigger
2. UNTimeIntervalNotificationTrigger
3. UNLocationNotificationTrigger

4. Create and register a Notification request

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

5. Schedule the request with the system

center.add(request) { (error) in
  if let error = error {
    print("request error: \(error)")
  }
}

6. In-app Notifications

Registering as the delegate for the UNNotificationCenterDelegate

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
  // Override point for customization after application launch.
  configureNoficationCenter()
  return true
}

Conforming to the UNNotificationCenterDelegate

extension AppDelegate: UNUserNotificationCenterDelegate {
  func configureNoficationCenter() {
    UNUserNotificationCenter.current().delegate = self
  }
  
  func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {
    // code here
  }
  
  func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
    completionHandler(.alert)
  }
}

7. Adding content attachments

let imageURL = Bundle.main.url(forResource: "pursuit-logo", withExtension: "png")!
do {
  let attachment = try UNNotificationAttachment(identifier: "sundayAlarm", url: imageURL)
  content.attachments = [attachment]
} catch {
  print("could not load attached with error: \(error)")
}

8. Get pending notification requests

UNUserNotificationCenter.current().getPendingNotificationRequests { (requests) in
  let request = requests.filter { $0.identifier == "sundayAlarm" }
  dump(request)
}

9. Remove a pending notification request

UNUserNotificationCenter.current().removePendingNotificationRequests(withIdentifiers: ["sundayAlarm"])

10. Adding a custom sound file

content.sound = UNNotificationSound(named: UNNotificationSoundName(rawValue: "deduction.mp3"))//.default