Swift - pushViewController from appDelegate, rootViewController.navigationController is nil

Question

Having a problem following a few guides, specifically http://blog.originate.com/blog/2014/04/22/deeplinking-in-ios/

I'm setting the url scheme and it's working well to launch the app from another app, but passing in the host or url are not working as it seems it should. I'm using storyboards and interface builder for all the view layouts.

The guide shows this openURL in appDelegate:

-(BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation{
    if([[url host] isEqualToString:@"page"]){
        if([[url path] isEqualToString:@"/page1"]){
            [self.mainController pushViewController:[[Page1ViewController alloc] init] animated:YES];
        }
    return YES;
    }
}

Here is my version simplified and in swift from a few other sources, ie Get Instance Of ViewController From AppDelegate In Swift I'm skipping the conditional for the url host at the moment to remove potential other variables in the problem.

func application(application: UIApplication, openURL url: NSURL, sourceApplication: String, annotation: AnyObject?) -> Bool {
    var rootViewController = self.window!.rootViewController
    let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
    var profileViewController = mainStoryboard.instantiateViewControllerWithIdentifier("profile") as ProfileViewController

    rootViewController.navigationController.popToViewController(profileViewController, animated: true)

    return true

}

The swift version causes a crash: fatal error: unexpectedly found nil while unwrapping an Optional value

It seems that rootViewController doesn't have a navigationController yet?

Maxim Kholyavkin · Accepted Answer · 2018-11-16 20:10:02Z

31

It seems that rootViewController actually is of type UINavigationController in my case, so casting it on declaration allowed me to call pushToViewController directly on it.

func application(application: UIApplication, openURL url: NSURL, sourceApplication: String, annotation: AnyObject?) -> Bool {
    let rootViewController = self.window!.rootViewController as! UINavigationController
    let mainStoryboard = UIStoryboard(name: "Main", bundle: nil)
    let profileViewController = mainStoryboard.instantiateViewController(withIdentifier: "InstructionVC") as! InstructionVC
    rootViewController.pushViewController(profileViewController, animated: true)
    return true

}

edited Nov 16, 2018 at 20:10

Maxim Kholyavkin

4,5932 gold badges39 silver badges84 bronze badges

answered Aug 12, 2014 at 15:06

tehfailsafe

3,4613 gold badges23 silver badges27 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Jared Over a year ago

I know this has been up for a year but i was wondering, if you push to a new view controller you instantiated, does this count as a segue where you can prepareforsegue?

bruth Over a year ago

Thank you thank you thank you. Was following some guides that were just grabbing the nav controller from the storyboard and it just wasn't working and this was the trick!

Kumar KL · Accepted Answer · 2018-10-23 12:08:38Z

26

SWIFT 4: Safe way to push with the use of conditional binding and Chaining

if let navController = self.navigationController, let viewController = self.storyboard?.instantiateViewController(withIdentifier: "indentfier") as? CustomViewController{
    navController.pushViewController(viewController, animated: true)
}

In One line of code :

Swift 3:

self.navigationController!.pushViewController(self.storyboar‌d!.instantiateViewCo‌ntroller(withIdentif‌ier: "view2") as UIViewController, animated: true)

self.navigationController!.pushViewController(self.storyboard!.instantiateViewControllerWithIdentifier("view2") as UIViewController, animated: true)

edited Oct 23, 2018 at 12:08

answered Nov 21, 2014 at 11:39

Kumar KL

15.3k9 gold badges40 silver badges62 bronze badges

4 Comments

nswamy Over a year ago

Swift 2.0

self.navigationController!.pushViewController(self.storyboard?.instantiateViewControllerWithIdentifier("view2") as! UIViewController, animated: true)

Sayalee Pote Over a year ago

Swift 3.0 self.navigationController!.pushViewController(self.storyboard!.instantiateViewController(withIdentifier: "view2") as UIViewController, animated: true)

Umit Kaya Over a year ago

self.navigationController is nil. how you push?

Kumar KL Over a year ago

@Umitk PushViewController is a part of Navigation API. So without 'UINavigationController' you cont push any. Updated answer to safest way to handle the push

Alvin George · Accepted Answer · 2015-09-24 05:43:38Z

9

APPDELEGATE TO PAGE:

        let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
        let loginPageView = mainStoryboard.instantiateViewControllerWithIdentifier("leadBidderPagerID") as! LeadBidderPage
        var rootViewController = self.window!.rootViewController as! UINavigationController
        rootViewController.pushViewController(loginPageView, animated: true)

PAGE TO PAGE:

        let loginPageView = self.storyboard?.instantiateViewControllerWithIdentifier("scoutPageID") as! ScoutPage
        self.navigationController?.pushViewController(loginPageView, animated: true)

edited Sep 24, 2015 at 5:43

answered Sep 24, 2015 at 4:44

Alvin George

14.3k95 silver badges64 bronze badges

1 Comment

Michael Yaworski Over a year ago

This was the only helpful post I saw in hours. Thanks. Page-to-page was what I was looking for.

Jeremy · Accepted Answer · 2017-07-31 08:21:36Z

2

Updated for swift 3/4. The most voted "one line of code" doesn't work because there's no navigation controller in "self"

let rootViewController = self.window!.rootViewController as! 
UINavigationController
let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let profileViewController = mainStoryboard.instantiateViewController(withIdentifier: "ProfileViewController") as! ProfileViewController
rootViewController.pushViewController(profileViewController, animated: true)

answered Jul 31, 2017 at 8:21

Jeremy

293 bronze badges

5 Comments

Rishabh Dugar Over a year ago

I dont find window in your solutin

Jeremy Over a year ago

@RishabhDugar Are you in AppDelegate class?

Rishabh Dugar Over a year ago

No I am in my Controller File

Jeremy Over a year ago

The solution is for getting the navigation controller from app delegate, not for view controller. In your case, the "one line of code" solution above might be what will work for you.

lapin Over a year ago

Signal SIGABRT on line rootViewController

Egzon P. · Accepted Answer · 2018-07-26 14:06:57Z

2

Swift 3 & 4 best practices to push viewcontroller from AppDelegate:

if let rootViewController = self.window!.rootViewController as? UINavigationController {
   let storyboard = UIStoryboard(name: "Main", bundle: nil)

   if let viewcontroller = storyboard.instantiateViewController(withIdentifier: "DiscussionBoardSID") as? DiscussionBoardViewController {
      viewcontroller.postID = "13" ///pass data to your viewcontroller
      rootViewController.pushViewController(viewcontroller, animated: true)
   }
}

answered Jul 26, 2018 at 14:06

Egzon P.

4,7983 gold badges34 silver badges32 bronze badges

Comments

José Raúl Toledano R · Accepted Answer · 2020-03-30 17:40:51Z

If you want to present and dismiss with NavigationBar or Dismiss(Animated: true, completion: nil) Set addObserver in didFinishLaunchingWithOptions

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



NotificationCenter.default.addObserver(self, selector: #selector(devolucionNoPresencial), name: NSNotification.Name(rawValue: "DevolucionNoPresencial"), object: nil)
        return true
}

then in your method

func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {
//do your code for .active, .inactive .background, etc

 if let userInfo = response.notification.request.content.userInfo as? [String : AnyObject] {
            if UIApplication.shared.applicationState == .active {
//activate the notificationCenter so you can call your @objc method
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "DevolucionNoPresencial"), object: nil)
}

add @objc method

@objc private func devolucionNoPresencial() {


       //change DevolucionVC for VC you want to present

        if let controller = DevolucionVC() as? DevolucionVC {
            if let window = self.window, let rootViewController = window.rootViewController {
                var currentController = rootViewController
                while let presentedController = currentController.presentedViewController {
                    currentController = presentedController
                }
                currentController.present(controller, animated: true, completion: nil)
            }
        }

    }

}

Anilkumar · Accepted Answer · 2017-04-10 08:37:57Z

-1

func pushNewView() {
    if let wind = UIApplication.sharedApplication().delegate?.window {
        if let rootViewController = wind?.rootViewController {
            let viewToPush = YourViewController()
            let nav1 = UINavigationController(rootViewController: viewToPush)
            if let alreadySomeOneThere = rootViewController.presentedViewController {
                alreadySomeOneThere.presentViewController(nav1, animated: true, completion: nil)
            }else {
                rootViewController.presentViewController(nav1, animated: true, completion: nil)
            }
        }
    }
}

answered Apr 10, 2017 at 8:37

Anilkumar

11 bronze badge

Collectives™ on Stack Overflow

Swift - pushViewController from appDelegate, rootViewController.navigationController is nil

7 Answers 7

2 Comments

4 Comments

1 Comment

5 Comments

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

7 Answers 7

2 Comments

4 Comments

1 Comment

5 Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related