Alternative to UserNotificationCenterDelegate's willPresent when app is in background

Question

I am trying to figure out whether I can accomplish my goal through Local Notifications, or whether I need to switch to Remote Notifications.

I\'m practicing iOS 10

Answer 1

For iOS 10 local notifications your out of luck.

For iOS 10 remote notifications —regardless of user interaction you can receive callbacks using application(_:didReceiveRemoteNotification:fetchCompletionHandler:). (It's kind of confusing that they deprecated most notification related methods but not this one)

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Callback for when app is in foreground and you're about to show the notification:

func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
    let content = notification.request.content
    // Process notification content

    completionHandler([.alert, .sound]) // Display notification as regular alert and play sound
}

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Callback for when app is either in background or in foreground and user tapped on an action:

e.g. gives you a callback that user tapped on Save.

func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {
    let actionIdentifier = response.actionIdentifier

    switch actionIdentifier {
    case UNNotificationDismissActionIdentifier: // Notification was dismissed by user
        // Do something
        completionHandler()
    case UNNotificationDefaultActionIdentifier: // App was opened from notification
        // Do something
        completionHandler()
    default:
        completionHandler()
    }
}

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Callback for when app is either in background, foreground or (possibly) suspended state and a Push Notifications (Remote or silent notification) arrives:

Prior to iOS10 when you tapped on the notification the application(_:didReceiveRemoteNotification:fetchCompletionHandler:) would get called.

But since iOS 10 application(_:didReceiveRemoteNotification:fetchCompletionHandler:) isn't called upon tapping. It's only called upon arrival of a remote Notification. (It get's called both in foreground and in background)

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For pre iOS 10, you can just use the old didReceiveLocalNotification function and capture the arrival of any notification.