Instantiate view, then navigate away - ios

Question

I'm currently writing an app where we are launching a walkthrough the first time the user opens the app. At the end of it, we require the user to fill in a few details, and to do so I would like him to press a button to get redirected to the settings page.
The thing is, this page is one level down the navigation controller (from the landing page). As it stands, I can correctly instantiate the landing page, but the redirection to the settings page never happens.
let mainView = self.storyboard?.instantiateViewControllerWithIdentifier("NavCtrl")
self.presentViewController(mainView!, animated: false, completion: nil)
// the above works correctly and sends us to the landing screen
// (rootView of the navigation controller)
// the following lines never have any effect though
let settingsView = self.storyboard?.instantiateViewControllerWithIdentifier("Settings View")
self.navigationController?.pushViewController(settingsView!, animated: false)
I think it's because I'm trying to call .pushViewController before the storyboard had time to instiate either the first or second view.
So I have a few questions:
Is there a way to, indeed, instantiate a view and then navigate to another one right after it has been instantiated ? (this in order to keep the navigation stack and maintain accurate nav bar behaviour)
If there isn't, would it be possible to programmatically populate the navigation stack so that I would only need to instantiate the settings view ? This in order to still have the back button in the nav bar that would send to the landing screen ?
Thanks in advance guys

Answer 1

Ok thanks to #Leonardo for showing me the correct direction !
I solved the issue by doing the following in appDelegate:
/*
* Override window root view and set it to a newly initialized one
* view: StoryboardID of view to display
* navigateTo: if true, set the root view to NavCtrl and then navigate to the desired view
*/
func setWindowViewTo(view: String, navigateTo: Bool) {
//initalize storyboard & window programmatically
window = UIWindow.init(frame: UIScreen.mainScreen().bounds)
let storyboard = UIStoryboard(name: "Main", bundle: nil)
//if true, navigate from landing page to specified view through navigationController
if(navigateTo) {
//instantiate the navigation controller
let navCtrl = storyboard.instantiateViewControllerWithIdentifier("NavCtrl") as! UINavigationController
//instantiate the landing page & the page we wish to navigate to
let landingView = storyboard.instantiateViewControllerWithIdentifier("Main View")
let vc = storyboard.instantiateViewControllerWithIdentifier(view)
//manually set the navigation stack to landing view + view to navigate to
navCtrl.setViewControllers([landingView, vc], animated: false)
//replace the rootViewController to the navigation controller
window!.rootViewController = navCtrl
//make it work
window!.makeKeyAndVisible()
} else {
window!.rootViewController = storyboard.instantiateViewControllerWithIdentifier(view)
window!.makeKeyAndVisible()
}
}
The important step was to indeed force downcast as! UINavigationController when instantiating the NavigationController with the storyboard.instantiateViewControllerWithIdentifier() method.
Then it's just a case to correctly instantiate the views of the navigation stack you want, and finally calling navCtrl.setViewControllers([view1, view2], animate: false).
Thanks all for your help !

Answer 2

You can use the - setViewControllers:animated: method to set the navigation stack of a UINavigationController
Here's the reference
But I don't think that's your problem, if I undestood your code correctly, it should be
//This is the navigation controller
if let mainView = self.storyboard?.instantiateViewControllerWithIdentifier("NavCtrl"){
//Nav being modally presented
self.presentViewController(mainView, animated: false, completion: nil)
// Instantiate the settings view
if let settingsView = self.storyboard?.instantiateViewControllerWithIdentifier("Settings View"){
//Push it to the navigation controller presented
mainView.pushViewController(settingsView, animated: false)
}
else{
//Can't Instantiate, deal with error
}
}
else{
//Can't Instantiate, deal with error
}