How do I make a UNUserNotification that's consistent through app states? - ios

Question

I make a UNUserNotification like this:
let content = UNMutableNotificationContent()
content.title = "a title"
content.body = "a body"
content.sound = .default
content.categoryIdentifier = "\(type(of: self))"
let request = UNNotificationRequest(
identifier: UUID().uuidString,
content: content,
trigger: UNTimeIntervalNotificationTrigger(timeInterval: 0.01, repeats: false)
)
let category = UNNotificationCategory(
identifier: content.categoryIdentifier,
actions: [
UNNotificationAction(identifier: Strings.accept.id, title: Strings.accept.title, options: [.authenticationRequired, .foreground]),
UNNotificationAction(identifier: Strings.reject.id, title: Strings.reject.title, options: [.authenticationRequired, .destructive])
],
intentIdentifiers: [],
options: .customDismissAction
)
It will show a notification with a title and body, and two custom action buttons (accept and reject, it's an incoming call). It plays a sound too, but for some reason not if the app is foregrounded.
I also try to fake a persistent notification with it, like the way Whatsapp does it by repeating a local notification every ~4 seconds, but the second time it shows the notification the sound is cut off a bit. It's not the sound of the first one, the second one shows with its own sound playing but this time it doesn't fully play out. The sound is only ~1-2 seconds.
I don't understand why there are these differences, how do I make it always play a sound (foreground, background, not running) and how do I make sure the sound is not cut off the second time the notification is shown?

Answer 1

When notifications are received whilst the app is running the notifications are normally silenced so that the app can handle them in a more native way.
If I remember rightly, receiving the notification will call:
func userNotificationCenter(_ center: UNUserNotificationCenter,
willPresent notification: UNNotification,
withCompletionHandler completionHandler:
#escaping (UNNotificationPresentationOptions) -> Void) {
if someCondition {
completionHandler(.alert)
} else {
completionHandler(.init(rawValue: 0))
}
}
This method is called when the notification is received and if the app is running in the foreground, it will normally be silenced. The completion handler determines what action should be taken and whether or not a notification should show or a sound made etc.
In this case if someCondition is true then it should show the notification natively as it normally would, otherwise dont do anything.
Try calling completionHandler(.alert) in this method in your app and your notifications should show
Checkout the documentation here