I have use the following code below . to navigate but i have tried all possible idea i have to navigate back but i always received an error. like Warning: Attempt to present on whose view is not in the window . when using the code below what is the best way to navigate back ? or to go to another view?
if let vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ScoreViewController") as? ScoreViewController
{
present(vc, animated: true, completion: nil)
}
If you are using NavigationController to push one ViewController to other then for navigate back you have to use Pop like this,
self.navigationController?.popViewController(animated: true)
and if you are using Modal Controller to present another Controller then for navigate back you have to use dismiss like this,
dismiss(animated: true, completion: nil)
Let me know in case of any queries.
You are presenting the view controller not pushing it. To come back to the controller, write down the below controller:-
dismiss(animated: true, completion: nil)
Related
I have been searching all day on how to present a view controller from within the appdelegate. It appears that in xcode 11 the window property was moved to the scenedelegate which has been confusing me. I want to present a view controller from within the appdelegate from the didReceiveRemoteNotification function so when the user receives a notification it takes them to a separate view controller with information. I have tried to do:
self.window?.rootViewController?.present(LoginViewController(), animated: false, completion: nil)
within the appdelegate which used to work in a previous application of mine but it does not seem to work anymore. Any help would be much appreciated.
I was able to solve this issue by using shared windows to get the window from scenedelegate to present the view controller on.
UIApplication.shared.windows.first?.rootViewController?.present(vc, animated: false, completion: nil)
Best approach to present view controller through app delegate is without falling for hierarchy like below:
if let vc = UIStoryboard(name: "YOURSTORYBOARD", bundle: nil).instantiateViewController(withIdentifier: "YOURVIEWCONTROLLER") as? YOURVIEWCONTROLLER {
if let window = self.window, let rootViewController = window.rootViewController {
var currentController = rootViewController
while let presentController = currentController.presentedViewController {
currentController = presentController
}
currentController.present(vc, animated: true, completion: nil)
}
}
I'm struggling to dismiss a UIViewController from the NavigationStack after login is completed.
The login screen is a UIViewController is presented with this line of code
let loginController = LoginController()
self.present(loginController, animated: true, completion: nil)
And then I run this code to log the user in via firebase.
Auth.auth().signIn(withEmail: email, password: password) { (user, err) in
if let err = err {
print("Failed to sign in user with email", err )
}
//self.dismiss(animated: true, completion: nil)
let userProfileVC = UserProfileController()
let navController = UINavigationController(rootViewController: userProfileVC)
self.navigationController?.pushViewController(navController, animated: true)
}
As you can see I have tried the pushViewController method, and have also tried the commented self.dismiss method? Nothing I do seems to remove the loginController UIView and take me back to the UINavigationController home screen. Can anyone help me out, thanks a lot.
you can do as this
self.dismiss(animated: true, completion: {
let userProfileVC = UserProfileController()
let navController = UINavigationController(rootViewController: userProfileVC)
self.navigationController?.pushViewController(navController, animated: true)
})
You might have to print your viewstack and show it to us in order to understand better but try one of these methods:
navigationController?.popViewController(animated: true)
or
navigationController?.popToRootViewController(animated: true)
The first method will dispose of the most recently pushed view controller, while the second will remove all but the navigation controllers "home screen" which you seek.
You can not push to particular controller while any controller is present on current controller. so you can use protocol delegate on controller which is present current controller. when delegate method called then you can push to your controller.
I have trouble in my application with swift 4.
I'd like to move my view controller automatically when my string get a value without nil. (Promatically)
However it does not work at all.
if(rst_str != nil){
let nextView = storyboard?.instantiateViewController(withIdentifier: "viewListController") as! ViewListController
//viewListController.delegate = self;
print("log storyboard");
self.present(nextView, animated: true, completion: nil);
}
The message of "log storyboard" is printed normally.
However the line of self.present is not working at all.
How can I resolve from my issue?
The line
self.present(nextView, animated: true, completion: nil);
won't work in 2 cases
1- the current vc you run this line in is currently not fully laid - out such as making it in viewDidLoad
2- the current vc is currently presenting another vc
Actually I am having navigationcontroller as root controller it is embed in main.storyboard,i am having two screens one screen login and another one home as per login credentials i need to skip login screen and i need to show home screen.From appdelegate i am doing this skipping it is not working properly
Unbalanced calls to begin/end appearance transitions for <UINavigationController: 0x7fadf384c600>.
let storyboard=UIStoryboard.init(name: "Main", bundle: nil)
let navigationController=storyboard.instantiateInitialViewController()
let username=UserDefaultUtil.getString(key: AppConstants.PREF_USERID)
print(username!)
if username != ""
{
window?.rootViewController=navigationController
let sectionController=SectionController(nibName: "SectionController" , bundle: nil)
navigationController?.present(sectionController, animated: true, completion: nil)
}
I guess you are trying to present your sectionController in navigationController, its not really how it works, try this code:
let navigationController = self.storyboard?.instantiateInitialViewController() as! UINavigationController
and replace the present with this:
navigationController.setViewControllers([sectionController], animated: false)
or just drop the navigationController instantiate and create it with code and set it as window?.rootViewController:
let sectionController=SectionController(nibName: "SectionController" , bundle: nil)
let nav = UINavigationController(rootViewController: sectionController)
window?.rootViewController = nav
First, check the user credentials in the login page. Then use:
if hasCredentials {
let vc:AnyObject! = self.storyboard?.instantiateViewController(withIdentifier: "someViewController")
self.show(vc as! UIViewController, sender: vc)
}
Sidenote: Personally, I do this from the login page because it simplifies the process and I do not like having weight sitting in my AppDelegate. If you were thinking you did not want people seeing your login screen who are already members, you can do it from an AppDelegate, but take into account the user experience might be diminished during the loading process if this is the route you decide to take.
AppDelegate
initialViewController = storyboard.instantiateViewControllerWithIdentifier("LoginViewController")as! UIViewController
}
self.window?.rootViewController = initialViewController
self.window?.makeKeyAndVisible()
Takes me to LoginViewController
let vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewControllerWithIdentifier("CardsNavController") as? UIViewController
self.presentViewController(vc!, animated: true, completion: nil)
I click on the login button takes me to CardsViewController
func goToProfile(button: UIBarButtonItem) {
pageController.goToPreviousVC()
}
Clicking on back button which is part of the UINavigationController runs goToProfile (above) and takes me to ViewController.swift because that's where the pageController is declared.
let pageController = ViewController(transitionStyle: UIPageViewControllerTransitionStyle.Scroll, navigationOrientation: UIPageViewControllerNavigationOrientation.Horizontal, options: nil)
The error shows up here
func goToPreviousVC() {
//let currentControllers = self.navigationController?.viewControllers
if viewControllers.isEmpty {
setViewControllers([profileVC], direction: UIPageViewControllerNavigationDirection.Reverse, animated: true, completion: nil)
pageController.presentViewController(profileVC, animated: true, completion: nil)
else {
let previousVC = pageViewController(self, viewControllerBeforeViewController: viewControllers[0] as! UIViewController)!
setViewControllers([previousVC], direction: UIPageViewControllerNavigationDirection.Reverse, animated: true, completion: nil)
}
Error:
Warning: Attempt to present <UINavigationController: 0x15ce314e0> on <MyApp.ViewController: 0x15cd2c6f0> whose view is not in the window hierarchy!
Basically the flow is like this AppDelegate -> LoginViewController -> ViewController and I need to get to ProfileViewController.
ProfileView has ProfileNavController while CardsView has CardsNavController
ViewController has a storyboardID of pageController.
Both ProfileView and and CardsView are embedded within UINavigationControllers (hence the NavController extension).
The second time I run the app after a fresh install it works perfectly (all the controllers get loaded okay). Should I push viewControllers in AppDelegate?
I've checked your code using Xcode 7, which may not be ideal for resolving this issue because I had to covert your code to Swift 2.0, but here was what I found out.
ISSUE
First time opening the app, this block:
if currentUser() != nil {
initialViewController = pageController
}
else {
initialViewController = storyboard.instantiateViewControllerWithIdentifier("LoginViewController") as UIViewController
}
self.window?.rootViewController = initialViewController
Will initialize LoginViewController and make it the current window's rootViewController.
At this point there is no pageController initialized
When user taps on the button to go to the Profile screen, this method will be called
func goToProfile(button: UIBarButtonItem) {
pageController.goToPreviousVC()
}
At this point, pageController is initialized, and off course, there is NOTHING in the viewControllers array. Let's see what happen in the goToPreviousVC method:
Original method looks like this:
let nextVC = pageViewController(self, viewControllerAfterViewController: viewControllers[0] as UIViewController)!
setViewControllers([nextVC], direction: UIPageViewControllerNavigationDirection.Forward, animated: true, completion: nil)
One thing you can see obviously is: calling viewControllers[0] could give you a crash because viewControllers is an empty array.
If you use Swift 2.0, it doesn't even let you compile your code :)
SOLUTION
Let's go directly to the solution: Ensure that the pageController is available before trying to call it's viewControllers.
I blindly tried fixing you code in Swift 2.0 and found out that this method would work for you:
BEFORE: In LoginViewController.swift line 63
let vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewControllerWithIdentifier("CardsNavController") as? UIViewController
self.presentViewController(vc!, animated: true, completion: nil)
AFTER: Let's fix it like this
let navc = UIStoryboard(name: "Main", bundle: nil).instantiateViewControllerWithIdentifier("CardsNavController") as! UINavigationController
if let viewControllers = pageController.viewControllers where viewControllers.count == 0 {
pageController.setViewControllers([navc.viewControllers[0]], direction: .Forward, animated: false, completion: nil)
}
self.presentViewController(pageController, animated: true, completion: nil)
It's working well here and probably I don't need to show you how the screen transition should look like :)
In case you would like to have the fixed source code as well, please find it HERE. Basically I converted your code to Swift 2.0 and ignored unnecessary parts like Facebook authentication for faster investigation.
Good luck & Happy coding!