How to call viewcontroller method from AppDelegate if I use TabBar Navigation - swift

Question

I really need a help with calling view controller method as soon as my app open when the remote notification comes in especially when using TabBar navigation.When I open my app when the notification arrive,it will call didReceiveRemoteNotification because I enabled "content-available = 1".But,the problem is I don't know how to access my HomeViewController method refresh() because I use TabBar Navigation.I need to call HomeViewController refresh() method inside didReceiveRemoteNotification because it really need to refresh the data from core and the notification that arrived are saved at coredata.
Everytime the notification comes in,I save them at realm database and show user at HomeViewController
func application(application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject], fetchCompletionHandler handler: (UIBackgroundFetchResult) -> Void) {
if let aps = userInfo["aps"] as? NSDictionary{
if let alert = aps["alert"] as? NSDictionary{
if let mbody = alert["body"] as? String{
print("Message Body : \(body)")
body = mbody
}
if let mtitle = alert["title"] as? String{
print("Message Title : \(title)")
title = mtitle
}
}
}
let newNotification = NotificationList()
newNotification.title = title
newNotification.body = body
//Realm insert query
oneSignalHelper.insertOneSignalNotification(newNotification)
print("Remote Receive")
//This condition isn't working
if let viewController = self.window?.rootViewController as? HomeViewController {
print("Remote Receive Read")
//This method is HomeViewController method which I gonna use for refresh when I tapped notification.It read that are save in realm database and show results.
viewController.readNotificationsAndUpdateUI()
}
handler(UIBackgroundFetchResult.NewData)
}
This is readNotificationsAndUpdateUI() from HomeViewController
func readNotificationsAndUpdateUI(){
notifications = realm.objects(NotificationList)
self.notificationTableView.setEditing(false, animated: true)
self.notificationTableView.reloadData()
self.refreshControl?.endRefreshing()
}

Answer 1

I suggest you using NSNotificationCenter, just post notification inside didReceiveRemoteNotification like this:
NSNotificationCenter.defaultCenter().postNotificationName("refreshNotification", object: nil)
In your HomeViewController in viewDidLoad() you should subscribe to the notification center like this:
NSNotificationCenter.defaultCenter().addObserver( self, selector: "refresh", name: "refreshNotification", object: nil)

Answer 2

Not sure if it helps but I solved it this way, based on previous answer
Load Storyboard
let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
Load ViewController (check that you have an identifier in your storyboard for this ViewController!)
let bestellvorschlag = storyBoard.instantiateViewController(identifier: "Bestellvorschlag") as! Bestellvorschlag
Load Function on ViewController
bestellvorschlag.loaddata() //Loads CoreData into Array of artikels
Maybe Modify the Tabbar Badge with the number of Results
let tabbarcontroller = self.window?.rootViewController as! UITabBarController
if bestellvorschlag.artikels.count > 0
{
if let tabItems = tabbarcontroller.tabBar.items {
// Third Tab!
let tabItem = tabItems[2]
tabItem.badgeValue = bestellvorschlag.artikels.count.description
}
}
Complete Function in appDelegate
func applicationDidBecomeActive(_ application: UIApplication) {
let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let bestellvorschlag = storyBoard.instantiateViewController(identifier: "Bestellvorschlag") as! Bestellvorschlag
bestellvorschlag.loaddata()
let tabbarcontroller = self.window?.rootViewController as! UITabBarController
if bestellvorschlag.artikels.count > 0
{
if let tabItems = tabbarcontroller.tabBar.items {
// Third Tab!
let tabItem = tabItems[2]
tabItem.badgeValue = bestellvorschlag.artikels.count.description
}
}
}