Updating a Tab Bar badge count from Push Notification when the app is in the foreground

Question

I have a Notifications Tab in my TabBarController that I would like to show the same badge count as the App badge count. I have it working in all scenarios except for when the app is in the foreground.

To do this I've created a custom class for my TabBarController which registers for the UIApplicationWillEnterForeground notification and sets the Notification tab's badge to equal the App badge. I also do this in the OnLoad() function.

Now how do I make the Notification Tab badge update when the app is already in the foreground? I capture the notification in the AppDelegate function:

    application(_:didReceiveRemoteNotification:fetchCompletionHandler:)

I know it may be possible to dig around the rootViewController to find the tab bar controller but my root controller is a my entry point to the app which checks if the user has a login token in the keychain and segues to either the login view controller or tab bar controller. So given that it segues I'm not sure this is an option?

Is it possible for my UI to register for a 'push notification' notification like the way I register to be notified of UIApplicationWillEnterForeground? This would be ideal but I haven't managed to find such a notification.

Any advice or tips would be appreciated!

Kamran Kamran · Accepted Answer · 2019-06-12T04:01:04

Post a notification from didReceiveRemoteNotification in AppDelegate and add an observer in your custom TabBarController to listen and update the UI as below,

class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

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

        return true
    }

    func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any]) {
        NotificationCenter.default.post(Notification(name: Notification.Name("didReceiveNotification")))
    }
}

class TabBarController: UITabBarController {

    override func viewDidLoad() {
        super.viewDidLoad()

        NotificationCenter.default.addObserver(
            self,
            selector: #selector(updateBadgeCount),
            name: Notification.Name(rawValue: "didReceiveNotification"),
            object: nil
        )
    }

    @objc private func updateBadgeCount() {
        // Update badge count
    }

    deinit {
        NotificationCenter.default.removeObserver(self)
    }
}

Updating a Tab Bar badge count from Push Notification when the app is in the foreground

1 Answers