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
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 !
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
}
Related
As you can see i have an initial view controller with label in it "Initial ViewController". In this view controller i use below code to go to selected tab of Tab Bar Controller
let vc1 = sb.instantiateViewController(withIdentifier: "tabbar") as! UITabBarController
vc1.selectedIndex = selected
let controllers = [vc1]
navigationController!.setViewControllers(controllers, animated: true)
In my First View, there's a button "Present VC" which presents "Presented View".
let vc1 = sb.instantiateViewController(withIdentifier: "PresentedVC") as! PresentedVC
present(vc1, animated: true, completion: nil)
Now i want to go back from presented vc to root vc(Initial View Controller). I can do this with:
let viewController = self.storyboard?.instantiateViewController(withIdentifier: "FirstNavigationController") as! FirstNavigationController
UIApplication.shared.keyWindow?.rootViewController = viewController
but this instantiate Initial View Controller every time and views remain in memory. How can i go back to Initial View Controller without instantiating it?
PS: FirstNavigationController is initial Navigation Controller.
At the very beginning you remove the initial view controller by doing this:
navigationController!.setViewControllers(controllers, animated: true)
All the previous viewControllers are gone now and replaced with the tabbar controller and its children.
If you want to go back to the initial controller, you will have to push the tabbar onto the stack instead of replacing everything with it. E.g.
navigationController?.pushViewController(tabbarVc, animated: true)
First when you did this
navigationController!.setViewControllers(controllers, animated: true)
the initial VC is deallocated (if it has not a strong references)
to keep it you can use push , pop instead of setViewControllers but note it may cause memory issues if you have heavy processing in your app as it will remain in navigationController stack
You are missing the concept between "Presenting" or "Setting" View Controller & "Navigating" the View Controller. You will get the answer, once you understood the concept. Here, it is..
When you are setting the ViewController, you are completely replacing the stack container to the new view controller. the way you did it here:
navigationController!.setViewControllers(controllers, animated: true)
In this case, STACK holds the addresses of the latest set/presented ViewControllers that means previous whole ViewController vanished.
On the other hand, if you are navigating to other view controller by pushing it. you can go back to previous controller by simple popping the ViewController address from stack. or to next ViewController by pushing
e.g:
self.navigationController?.pushViewController(tabbarVc, animated: true)
self.navigationController?.popViewController(animated: true)
Summary:
If you push TabBarController then, only you will get InitialVC.
Now, in your case, you are setting the ViewController and hence, you are not getting InivtialVC. Try Pushing tabbarVC This will work.
navigationController?.pushViewController(tabbarVc, animated: true)
We are looking to change the way a user logs out of our app. In order to do that, we want to dismiss all the VCs below the current VC and put another VC on top as the root VC. Right now we are doing this which I believe does not dismiss any VC below from memory.
let viewController = storyboard?.instantiateViewController(withIdentifier: "SignIn")
if let unwrappedViewController = viewController {
self.present(unwrappedViewController, animated: true, completion: {})
}
The problem is that the VC that we want to put on top is not embedded in a Navigation Controller or tab bar controller. How would we dismiss the VCs and set the new VC as the main VC as if the user was opening the app for the first time without having previously logged in? We also do want the transition to be animated with whatever animation is normal for that event (modal animation is fine). I have read a bunch of different ways on doing it but I want to know which way is best practice and should be implemented specifically dismissing all VCs and putting a new VC that isn't in a Nav controller on top.
If you can access the UIWindow of the app, you can set its rootViewController property to your sign-in view controller, effectively removing all current view controllers and adding the sign-in view controller instead. Here's an example:
guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else { return }
// Should remove all subsequent view controllers from memory.
appDelegate.window?.rootViewController.dismiss(animated: true, completion: nil)
// Set the root view controller to a new instance of the sign in view controller.
appDelegate.window?.rootViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "SignIn")
So i have an app were you're supposed to chose a location from a map but the way i'm doing it is by a popup off a view controller that has a MapKit and a search bar and a button for choosing users location, the problem lies on when i'm done with the View I normally called the
self.view.removeFromSuperview()
but the thing that is being remove is the View controller itself but il leaves behind the navigation bar and it doesn't let me do nothing else (in fact when I go to another tab and return to the same one the VC returns).
the way i'm instantiating the VC is like this:
func location ()
{
let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let vc = mainStoryboard.instantiateViewController(withIdentifier: "mapV") as! UBICACIONViewController
let nav1 = UINavigationController()
nav1.viewControllers = [vc]
self.addChildViewController(nav1)
self.view.addSubview(nav1.view)
vc.delegate = self //this for the info that i'm getting afte(works fine)
nav1.didMove(toParentViewController: self)
}
So until here works fin but when the user pick te button that says "Use My Location" and tries to return there's the problem.
in my VC view controller this is what happens when finished:
func Remove()
{
if let del = delegate {
del.dataChanged(str: Event.sharedInstance.Location!)
}
self.view.removeFromSuperview() //Problem Here :/
}
Second VC
Return to First VC
Actually you have added a child view controller nav1. And nav1 has a subview nav1.view.
while removing you are removing this view from its superview, not the child view controller added.
Any ways, From you screen short..I understand that the pop up view is off full screen then why dont you present this VC modally, or else push it to navigation stack.
I have a tab bar in my app and one of the buttons is "Profile" which should present one VC if user not authorized and another if user already authorized.
So... Things work, but not correctly. Looks like I messed up some root controllers. Sometimes I cant pop up vc or change the color of a nav bar title.
I create a custom navigation controller with that code inside
if NSUserDefaults.standardUserDefaults().objectForKey("userId") != nil {
let newController: UserViewController = self.storyboard?.instantiateViewControllerWithIdentifier("userViewController") as! UserViewController
self.setViewControllers([newController], animated: false)
} else {
let newController: LoginViewController = self.storyboard?.instantiateViewControllerWithIdentifier("loginViewController") as! LoginViewController
self.setViewControllers([newController], animated: false)
}
Is there a way to implement in correctly?
You're trying to instantiate a Navigation Controller - which (as #PierreMB had mentioned) won't work. You should instead create two regular View Controllers with storyboard ID's "userViewController" and "loginViewController", and instantiate them.
Create a UINavigationController subclass, and put this code (which you wrote, slightly modified) in its viewWillAppear() method (as a bonus, you can pass the 'animated' parameter free of charge):
if NSUserDefaults.standardUserDefaults().objectForKey("userId") != nil {
let newController = self.storyboard?.instantiateViewControllerWithIdentifier("userViewController") // drop the 'as! UINavigationController'
self.setViewControllers([newController], animated: animated)
} else {
let newController = self.storyboard?.instantiateViewControllerWithIdentifier("loginViewController") // drop the 'as! UINavigationController'
self.setViewControllers([newController], animated: animated)
}
The function instantiateViewControllerWithIdentifier() by default returns a UIViewController, which is what you really want to display.
Are you trying to put a UINavigationController as a root of another UINavigationController ? Because it is prohibited and doesn't work well.
I am trying to display a fix navigation bar for my UiTableViewController, I have a first ViewController and when I click on it, this will open my UITableViewController Here is the code of the click :
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("MyTableViewController") as! MyTableViewController
vc.myObject = object // I pass some data
presentViewController(vc, animated: true, completion: nil)
the UItableView is correctly display but not navigation bar appear, if I add one, the navigation bar scroll with the table view and I don't want this behavior.
I tried this without success :
Go to the Editor menu, and click on the Embed In submenu, and choose
Navigation Controller
And tried to change some settings here :
Actually, in your case you want to show navigation and for navigation you have to push your view controller to a UINavigationController thats why the solution is :
let vc = storyboard.instantiateViewControllerWithIdentifier("MyTableViewController") as! MyTableViewController
vc.myObject = object // I pass some data
self.navigationController?.pushViewController(vc, animated: true)
presentViewController offers a mechanism to display a modal view controller; i.e., a view controller that will take full control of your UI by being superimposed on top of a parent controller & establish a parent child relation b/w presenting & presented view controllers.
where as
pushViewController offers a much more flexible navigation process where you can push & pop a new controller to UINavigationController, so to go back to the previous one, in a ordered way. Imagine that controllers in a navigation controller will just build a sequence from left to right like building a stack of view controllers stacking upon each other.
Do it this way:
let vc = storyboard.instantiateViewControllerWithIdentifier("MyTableViewController") as! MyTableViewController
vc.myObject = object // I pass some data
self.navigationController?.pushViewController(vc, animated: true)