ios - Opening ViewController In AppDelegate While Keeping Tabbar

Question

In my Xcode project when a user taps on a notification I want to first send them to a certain item in my tabBar then I want to instantiate a view controller and send an object over to that view controller. I have code the that sends them to the tabBar I want, but I do not know how to instantiate them to the view controller while keeping the tabBar and navigation bar connected to the view controller. All the answers on this require you to change the root view controller and that makes me lose connection to my tabBar and navigation bar when the view controller is called.

A Real Life Example of this: User receives Instagram notification saying "John started following you" -> user taps on notification -> Instagram opens and shows notifications tab -> quickly send user to "John" profile and when the user presses the back button, it sends them back to the notification tab

Should know: The reason why I'm going to a certain tab first is to get that tab's navigation controller because the view controller I'm going to does not have one.

Here's my working code on sending the user to "notifications" tab (I added comments to act like the Instagram example for better understanding):

if let tabbarController = self.window!.rootViewController as? UITabBarController {
    tabbarController.selectedViewController = tabbarController.viewControllers?[3] //goes to notifications tab
    if type == "follow" { //someone started following current user                            
        //send to user's profile and send the user's id so the app can find all the information of the user                    
    }
}

Answer 1

First of all, you'll to insatiate a TabBarController:

let storyboard = UIStoryboard.init(name: "YourStoryboardName", bundle: nil)
let tabBarController = storyboard.instantiateViewController(withIdentifier: "YourTabBarController") as! UITabBarController

And then insatiate all of the viewControllers of TabBarController. If your viewControllers is embedded in to the UINavigationController? If so, you'll to insatiate a Navigation Controller instead:

let first = storyboard.instantiateViewiController(withIdentifier: "YourFirstNavigationController") as! UINavigationController
let second = storyboard.instantiateViewiController(withIdentifier: "YourSecondNavigationController") as! UINavigationController
let third = storyboard.instantiateViewiController(withIdentifier: "YourThirdNavigationController") as! UINavigationController

Also you should instantiate your desired ViewController too:

let desiredVC = storyboard.instantiateViewController(withIdentifier: "desiredVC") as! ExampleDesiredViewController

Make all of the NavigationControllers as viewControllers of TabBarController:

tabBarController.viewControllers = [first, second, third]

And check: It's about your choice.

if tabBarController.selectedViewController == first {

// Option 1: If you want to present
first.present(desiredVC, animated: true, completion: nil)

// Option 2: If you want to push
first.pushViewController(desiredVC, animated. true)

}

Make tabBarController as a rootViewController:

self.window = UIWindow.init(frame: UIScreen.main.bounds)   
self.window?.rootViewController = tabBarController
self.window?.makeKeyAndVisible()

Finally: It's your completed code:

func openViewController() {

let storyboard = UIStoryboard.init(name: "YourStoryboardName", bundle: nil)
let tabBarController = storyboard.instantiateViewController(withIdentifier: "YourTabBarController") as! UITabBarController

let first = storyboard.instantiateViewiController(withIdentifier: "YourFirstNavigationController") as! UINavigationController
let second = storyboard.instantiateViewiController(withIdentifier: "YourSecondNavigationController") as! UINavigationController
let third = storyboard.instantiateViewiController(withIdentifier: "YourThirdNavigationController") as! UINavigationController

let desiredVC = storyboard.instantiateViewController(withIdentifier: "desiredVC") as! ExampleDesiredViewController

tabBarController.viewControllers = [first, second, third]

if tabBarController.selectedViewController == first {

// Option 1: If you want to present
first.present(desiredVC, animated: true, completion: nil)

// Option 2: If you want to push
first.pushViewController(desiredVC, animated. true)

}

self.window = UIWindow.init(frame: UIScreen.main.bounds)   
self.window?.rootViewController = tabBarController
self.window?.makeKeyAndVisible()

}

If you want to present or push ViewController when the notification is tapped? Try something like that:

extension AppDelegate: UNUserNotificationCenterDelegate {

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

        switch response.actionIdentifier {
        case UNNotificationDefaultActionIdentifier:
            openViewController()
            completionHandler()

        default:
            break;
        }
    }
}