newbie here... my root view controller has the following code:
func showVC1() {
let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let vc1 = storyBoard.instantiateViewController(withIdentifier: "first")
self.present(vc1, animated:true, completion:nil)
}
func showVC2() {
let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let vc2 = storyBoard.instantiateViewController(withIdentifier: "second")
self.present(vc2, animated:true, completion:nil)
}
I can call these functions in either order, the first works fine, but the second will give me an error like "Attempt to present on whose view is not in the window hierarchy!"
I think I want to keep all of my code in the root vc that contains these functions. How can I make this work?
I'm also concerned that each time I call these functions I'll be creating new vc instances which will use more memory. Is there a way to keep a reference to these vc's outside of these functions? And will that solve the hierarchy issue?
Yes, second gives an error because you are trying to present two view controller at the same time from root view controller.
You can create lazy references to these view controllers
lazy var firstViewController : FirstViewController = {
let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let vc1 = storyBoard.instantiateViewController(withIdentifier: "FirstViewController") as! FirstViewController
return vc1
}()
#IBAction func buttonPressed(_ sender: Any) {
self.present(firstViewController, animated:true, completion:nil)
}
Instead of presenting a new view controller try to push that one into the navigation stack like
self.navigationController.pushViewController(controller, animated: false)
Because if you present anything on your controller it will not continue the navigation. which will lead to crash
Related
I am using Xcode 11 and Swift 5.
Upon receiving an APNS notification, I need to jump to a view controller deep in my storyboard from AppDelegate. This viewController (chatVC) is behind a tabbar and a navigation controller and several other view controllers. See the image below. I know how to check the notification for tags and how to use launchOptions in AppDelegate to trigger the jump. But I am struggling with how to establish the context for that last view controller so that the user can use the back button all the way back to the tab bar controller.
I have read many SO answers, and tried many approaches but none seem to have the same embedding of a nav controller inside a tab bar controller. Here is my code in AppDelegate (after reading the tag in the notification):
if tag == "CS" {
// Set up a Chat View Controller.
if let chatVC = UIStoryboard(name: "Main", bundle: .main).instantiateViewController(withIdentifier: Constants.Storyboard.chatVC) as? NewChatViewController,
let tabBarVC = UIStoryboard(name: "Main", bundle: .main).instantiateViewController(withIdentifier: Constants.Storyboard.tabBarController) as? UITabBarController,
let csVC = UIStoryboard(name: "Main", bundle: .main).instantiateViewController(withIdentifier: Constants.Storyboard.csViewController) as? CustomerServiceViewController,
let helpVC = UIStoryboard(name:"Main", bundle: .main).instantiateViewController(withIdentifier: Constants.Storyboard.helpVC) as? HelpViewController
{
// Set the customer service document Id.
chatVC.cs = cs
// Make the tabBarVC the Root View Controller
self.window?.rootViewController = tabBarVC
self.window?.makeKeyAndVisible()
// Select the Favorites Index.
tabBarVC.selectedIndex = 0
// Push the Customer Service VC on top.
tabBarVC.show(csVC, sender: Any?.self)
// Push the Help VC on top of Customer Service VC.
csVC.show(helpVC, sender: Any?.self)
// Push the the chat detail page on top.
helpVC.show(chatVC, sender: Any?.self)
}
}
}
return true
What can I do to jump to the chatVC and set up the navigation context beneath it so the back button can be used?
Here is how you can do it:
guard let tabBarVC = UIApplication.shared.windows.filter( {$0.rootViewController is UITabBarController } ).first?.rootViewController as? UITabBarController else { return }
tabBarVC.selectedIndex = 0 //you can select another tab if needed
guard let chatVC = UIStoryboard(name: "Main", bundle: .main).instantiateViewController(withIdentifier: Constants.Storyboard.chatVC) as? NewChatViewController else { return }
if let navController = tabBarVC.viewControllers?[0] as? UINavigationController {
navController.pushViewController(chatVC, animated: true)
}
You can also pass objects from your notification to your chatVC here before pushing it, in case you need to do that.
Hope this works for you!
I'm in a storyboard and I need to go to another storyboard by tapping a button. Well, this I've already done, but I need to go back to previous storyboard. Here is my code:
func goContact() {
let storyboard = UIStoryboard(name: "FAQ", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "ContactViewController")
self.navigationController?.show(vc, sender: nil)
}
By tapping a button on my UITableViewCell (where I have a protocol), this function (goContact) is called and I switch to another storyboard (FAQ). But, how can I go back to main.storyboard?
I've already tried do this too:
func goContact() {
let storyboard = UIStoryboard(name: "FAQ", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "ContactViewController")
self.navigationController?.show(vc, sender: nil)
// self.navigationController?.pushViewController(vc, animated: true)
// self.present(vc, animated: true, completion: nil)
}
Use only storyboard property , it references to Main storyboard of the app or you can write it like let storyboard = UIStoryboard(name: "Main", bundle: nil)
To go back after push do
self.navigationController?.popViewController(animated: true)
You should push your new view controller onto the navigation controller using push, like in your commented-out code. That will cause the new view controller to have a back button, which will pop it for you without needing any extra code.
I have a case in one of my Swift files which runs the following method:
case .editProfile:
vc = PoiDetailViewController()
self.navigationController?.popViewController(vc,animated: true)
It doesn't seem to work when I run the code.
The view controller is located on the main storyboard and I would like PoiDetailViewController to display when this case is called.
If I understand it correctly, you should be able to achieve what you're looking for by present in your code. Like so:
case .editProfile:
let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyBoard.instantiateViewController(withIdentifier: "PoiDetailViewController") // or whatever identifier you have given it
self.present(vc, animated: true, completion: nil)
That should work, however, make sure you set a storyboard ID for your view controller in the identity inspector.
No segues are required.
To set up a storyboard ID click on the View Controller you would like to use (in this case, PoiDetailViewController) and click the identity inspector icon and set a storyboard ID where it asks. I have attached an image so you can see where it needs to go (in the field marked 'Storyboard ID')
Hope that helps.
As per my Understanding you need to pop to specific View Controller if it is in stack and if not then you need to push to that controller
var loginVCFound:Bool = false;
let navigationController : UINavigationController! = self.window!.rootViewController as! UINavigationController;
let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil);
let viewControllers: [UIViewController] = navigationController.viewControllers
for aViewController in viewControllers {
if aViewController is LoginVC {// Pass the name of your controller here
loginVCFound = true;
navigationController.popToViewController(aViewController, animated: true)
break;
}
}
if !loginVCFound { // change the identifier and VC with yours
let objLoginVC = mainStoryboard.instantiateViewController(withIdentifier: "LoginVC") as! LoginVC
navigationController.pushViewController(objLoginVC, animated: true)
}
I have 3 items in my storyboard. 1. viewController (A) connected to 2. Navigation controller and 3. viewController (B) is NOT connected to anything
All 3 items have restoration identifiers set in the storyboard.
viewController (B) is the initial view controller.
I am trying in B to get the navigation controller that A is attached to, but always returns nil:
let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyBoard.instantiateViewControllerWithIdentifier("viewControllerA") as! ViewControllerA
print(vc.navigationController?) // always prints nil
why!?
UPDATE#1
I can't declare a UINavigationController like a view controller. I've tried setting navigationcontroller with the id of 'myNavigationController' as storyboardID:
When storyboard, I get this error
let navigationController = storyBoard.instantiateViewControllerWithIdentifier("myNavigationController") as! UINavigationController
print(self.navigationController!) // fatal error: unexpectedly found nil while unwrapping an Optional value
I've also tried setting the id in restoration identifier, It bombed earlier at the instantiating line
#ColdLogic, see what hits I get when I search the entire project for that identifier:
Because you never instantiated the navigation controller, you instantiated view controller A. You would want something like this if you want both the nav controller and the view controller to be setup like they are in the storyboard
let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let navigationController = storyBoard.instantiateViewControllerWithIdentifier("YourNavControllerIdentifier") as! UINavigationController
let vc = navigationController.topViewController as! ViewControllerA
Your code directly instantiates an object of type ViewControllerA. Which, unless you setup logic to do it, does not have a navigation controller by default.
This Worked for me!
let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let navigationController = storyBoard.instantiateViewController(withIdentifier: "HomeNavigationContoller") as! UINavigationController
let viewController = storyBoard.instantiateViewController(withIdentifier: "HomeViewController") as! HomeViewController
navigationController.pushViewController(messageVC, animated: true)
self.present(navigationController, animated: true, completion: nil)
Use NavigationController identifier to access the NavigationController and ViewController A is already attached to it, so it will automatically get loaded to NavigationController
I want to have a button on my navigation bar "Reset" and I would like this to be connected to an IBAction to sort of "restart" the controller.
I have some segues from another controller that changes some aspects of the viewcontroller (that has a collectionview) and I want the user to be able to start over. Does anyone have any suggestions as to how to proceed?
If you embed navigation controller to your view controller then you can use this code:
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("ViewController")
let viewcontrollers = self.navigationController.viewControllers
viewcontrollers.removeLast()
viewcontrollers.append(vc)
self.navigationControllers?.setViewControllers(viewcontrollers, animate: true)
You can change rootViewController of your application:
UIApplication.shared.keyWindow?.rootViewController = UIViewController()
This is how I do it in Swift 2.1 with my Home view inside a UINavigationController:
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let homeVC = storyboard.instantiateViewControllerWithIdentifier("HomeViewController")
self.navigationController?.presentViewController(homeVC, animated: false, completion: nil)
self.navigationController?.dismissViewControllerAnimated(false, completion: nil)