SWIFT send local notification - swift

Question

i'm trying to send a local notification following this tutorial:
https://useyourloaf.com/blog/local-notifications-with-ios-10/
I added this code to my viewDidLoad():
let center = UNUserNotificationCenter.current()
let options: UNAuthorizationOptions = [.alert, .sound];
center.requestAuthorization(options: options) {
(granted, error) in
if !granted {
print("Something went wrong")
}
}
let content = UNMutableNotificationContent()
content.title = "Don't forget"
content.body = "Buy some milk"
content.sound = UNNotificationSound.default()
let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 5,
repeats: false)
let identifier = "UYLLocalNotification"
let request = UNNotificationRequest(identifier: identifier,
content: content, trigger: trigger)
center.add(request, withCompletionHandler: { (error) in
if let error = error {
print("error")
}
})
but 5 seconds pass without any notification shown. the CompletionHandler is called with error being nil

Answer 1

If you want the notification when app is in foreground, then you'll have to add some more code into your controller,
Add the following line at the end of viewDidLoad()
center.delegate = self
This makes your ViewController the delegate to which the notification can callback when it hits.
Confirm your view controller to the delegate, (Add UNUserNotificationCenterDelegate)
class ViewController: UIViewController, UNUserNotificationCenterDelegate {
Now you can write callback methods in your ViewController.
Write the callback to present your notification, you can add this method right after viewDidLoad()
func userNotificationCenter(_ center: UNUserNotificationCenter,
willPresent notification: UNNotification,
withCompletionHandler completionHandler: #escaping (UNNotificationPresentationOptions) -> Void) {
completionHandler([.alert, .badge, .sound])
}
This will make your notification to popup even if the app is in foreground.
NOTE: It is highly recommended that you register your notifications (Local/Remote) in AppDelegate rather than ViewController.