I want to present two view controllers in a row, without seeing the first one.
I want to be able to return from the second one to the first.
I have read this post, but the responses focus on using the navigation controller, while I want to present the second view controller modally.
The use case is: My initial VC check if the user is logged in, and presents the login VC if not.
If yes, it displays the main VC.
On logout, I should be able to unwind to the login VC.
A suitable solution would be presenting the second view controller first and only presenting the first one after the second one fully appeared.
InitialViewController
let secondVc = storyboard!.instantiateViewController(withIdentifier: "Second") as! SecondViewController
secondVc.initialVc = self
present(secondVc, animated: true)
SecondViewController
fileprivate var firstViewDidAppearTime = true
var initialVc: InitialViewController!
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
if firstViewDidAppearTime {
firstViewDidAppearTime = false
let firstVc = storyboard!.instantiateViewController(withIdentifier: "First")
initialVc.present(firstVc, animated: false)
}
}
Related
I'm new to iOS.
I have an app where the path through the app can vary depending on the configuration I fetch from an API. Because of this, I don't use segues because I would need to create a segue from each ViewController (VC) to EVERY other VC. It creates a mess of segues that I don't want. So Instead I navigate from screen to screen like this:
func navigate(to viewController: String) {
let storyboard = UIStoryboard(name: K.mainStoryBoard, bundle: nil)
let nextVC = storyboard.instantiateViewController(identifier: viewController)
self.present(nextVC, animated: true, completion: nil)
}
My question is this: If I would have embedded my VCs in a NavigationController I know it would have created a stack. When I get to the last screen I would call func popToRootViewController(animated: Bool) -> [UIViewController]? and start from the beginning. However, I don't use a NavigationController. So, does that mean that when I present the next VC it replaces the previous one or does it stack on top of the previous one? I'm trying to prevent memory leaks so I want to make sure I don't keep stacking the VCs on top of each other until my app runs out of memory and crashes.
Thanks in advance
Edit
So, in my final VC I created an unwind segue. And I call it like this: performSegue(withIdentifier: "unwindToMain", sender: self)
and In my first VC (the initial VC in my app) I write this:
#IBAction func unwind( _ seg: UIStoryboardSegue) {
}
Everything works fine the first trip through the app. The last VC unwinds back to the fist VC. The problem is now that when I try to run through the app again (starting from VC 1 and then going to the next one) I now get this error:
MyApp[71199:4203602] [Presentation] Attempt to present <MyApp.DOBViewController: 0x1038760c0> on <MyApp.ThankYouViewController: 0x112560c30> (from <MyApp.ThankYouViewController: 0x112560c30>) whose view is not in the window hierarchy.
To make sense of this, DOBViewController would be the second VC I want to go to from the MainVC. ThankYouViewController is my last VC. It looks as if it isn't completely removed from the stack. Can anyone tell me what's going on?
Here is a very simple, basic example...
The controllers are setup in Storyboard, each with a single button, connected to the corresponding #IBAction.
The DOBViewController has its Storyboard ID set to "dobVC".
The ThankYouViewController has its Storyboard ID set to "tyVC".
MainVC is embedded in a navigation controller (in Storyboard) and the navigation controller is set to Initial View Controller:
class MainVC: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
navigationController?.setNavigationBarHidden(true, animated: false)
}
#IBAction func pushToDOB(_ sender: Any) {
if let vc = storyboard?.instantiateViewController(withIdentifier: "dobVC") as? DOBViewController {
navigationController?.pushViewController(vc, animated: true)
}
}
}
class DOBViewController: UIViewController {
#IBAction func pushToTY(_ sender: Any) {
if let vc = storyboard?.instantiateViewController(withIdentifier: "tyVC") as? ThankYouViewController {
navigationController?.pushViewController(vc, animated: true)
}
}
}
class ThankYouViewController: UIViewController {
#IBAction func popToRoot(_ sender: Any) {
navigationController?.popToRootViewController(animated: true)
}
}
does that mean that when I present the next VC it replaces the previous one or does it stack on top of the previous one?
The new one stacks on top of the previous one.
When you present a view controller, like
self.present(nextVC, animated: true, completion: nil)
The one you called .present on (self in this case) becomes presentingViewController for the nextVC instance.
The one you presented (nextVC in this case) becomes presentedViewController for the self instance.
I have two view controllers, first view controller and the second view controller, when the user segue from the first view controller to the second view controller, the first view controller still visible and sits behind the second view controller. The user can swipe the first view controller and see the entire first view controller and then they got stuck there. I noticed that this only happens after the launch of iOS 13.
performSegue(withIdentifier: "showSecond", sender: self)
Follow these two steps:
Click on the segue you created on the Storyboard
Go to Attributes Inspector
Set the Presentation to "Full Screen"
#Maysam is 100% right! But you can also do it programmatically through this:
// Go to next View Controller
#IBAction func nextTextVC(_ sender: UIButton) {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let nextInfo = storyboard.instantiateViewController(identifier: "socialOptionsIntroViewController")
self.navigationController?.pushViewController(nextInfo, animated: true)
}
There is a more detail thread could answer this question.
The follow solution from Pratik Sodha
let controller = UIViewController()
let navigationController = UINavigationController(rootViewController: controller)
navigationController.modalPresentationStyle = .overCurrentContext
self.navigationController?.present(navigationController, animated: true, completion: nil)
I have 3 ViewController : LoginViewController, CheckinViewController, & ProfileViewController
The flow is :
LoginVC --> CheckinVC --> ProfileVC
What i need is:
I want to dismiss "ProfileVC" & "CheckinVC" when click logout button in "ProfileVC" then go back to the "LoginVC"
LoginVC.swift
let checkinViewController = self.storyboard?.instantiateViewController(withIdentifier: "CheckinViewController") as! CheckinViewController
self.navigationController?.pushViewController(checkinViewController, animated: true)
JustHUD.shared.hide()
self.dismiss(animated: false, completion: nil)
CheckinVC.swift
if let profileView = self.storyboard?.instantiateViewController(withIdentifier: "ProfileViewController") {
profileView.providesPresentationContextTransitionStyle = true
profileView.definesPresentationContext = true
profileView.modalPresentationStyle = UIModalPresentationStyle.overCurrentContext;
// profileView.view.backgroundColor = UIColor.init(white: 0.4, alpha: 0.8)
profileView.view.backgroundColor = UIColor.clear
profileView.view.isOpaque = false
self.present(profileView, animated: true, completion: nil)
Here is i'm trying to do
ProfileVC.swift
#IBAction func clickLogout(_ sender: Any) {
UserDefaults.standard.removePersistentDomain(forName: Bundle.main.bundleIdentifier!)
UserDefaults.standard.synchronize()
self.dismiss(animated: false, completion: {
print("ProfileView : dismiss completed")
let loginViewController = self.storyboard?.instantiateViewController(withIdentifier: "LoginViewController") as! LoginViewController
self.navigationController?.pushViewController(loginViewController, animated: true)
self.dismiss(animated: false, completion: {
print("SUCCESS")
})
})
}
Well you need to do an Unwind Segue so you can go back in your LoginVC.
Follow these simple four steps to create Unwind segues:
In the view controller you are trying to go back to, LoginVC in your example, write this code:
#IBAction func unwindToVC1(segue:UIStoryboardSegue) { }
( Remember: It’s important to insert this method in the view
controller you are trying to go back TO! )
In the Storyboard, go to the screen you’re trying to unwind from ( ProfileVC in our case ), and control + drag the viewController icon to the Exit icon located on top.
3. Go to the document outline of the selected viewController in the Storyboard, select the unwind segue as shown below.
Now, go to the Attributes Inspector in the Utilities Pane and name the identifier of the unwind segue.
Finally, write this code where you want the unwind segue action to be triggered, ProfileVC in our case.
#IBAction func clickLogout(_ sender: Any) {
UserDefaults.standard.removePersistentDomain(forName: Bundle.main.bundleIdentifier!)
UserDefaults.standard.synchronize()
performSegue(withIdentifier: "unwindSegueToVC1", sender: self)
}
For more information check Create Unwind Segues
While Enea Dume's solution is correct if you want to use storyboards, here is the explanation of the problem, and the solution if you want to do it in code like you have been so far.
The Issue
If we focus on the self.dismiss calls in the logoutFunction in ProfileVC, this is what happens.
The first time you call self.dismiss, ProfileVC will dismiss itself and be removed from the view stack.
In the completion delegate, you are pushing a new LoginVC to a navigation controller. However, the CheckIN VC is presented over the navigation controller so you can't see anything happen.
The second call to self.dismiss does nothing as ProfileVC is not presenting any other view controllers and it is not in the stack any longer.
The Solution
You need to keep a reference to LoginVC that presented the CheckInVC. If you call "reference to LoginVC".dismiss, it will dismiss the view controllers above it in the stack and take you back to the login view controller.
In the class CheckinVC.swift, in the function viewDidAppear, check if the user is still active or not based on the session that you are maintaining and the pop to login view controller accordingly. If user status is logged out, then it will go to login view controller. Else it will work as usual.
Problem is that you are trying to dismiss twice ProfileVC but what you actually need is to dismiss it and then pop CheckinVC.
Also after dismissing a view controller it no longer has a reference to the NavigationController so you need a reference to it in a temporal variable.
Change ProfileVC like this:
#IBAction func clickLogout(_ sender: Any) {
UserDefaults.standard.removePersistentDomain(forName: Bundle.main.bundleIdentifier!)
UserDefaults.standard.synchronize()
let navigationController = self.navigationController
let loginViewController = storyboard?.instantiateViewController(withIdentifier: "LoginViewController") as! LoginViewController
self.dismiss(animated: false, completion: {
print("ProfileView : dismiss completed")
navigationController?.pushViewController(loginViewController, animated: true)
navigationController?.popViewController(animated: false)
})
}
What I am trying to do is present a viewController and when the user touches a button I want to call popViewController and then present a different viewController. But I cannot figure out how to do it.
Some of the things I have tried are call pop and then immediately call present, call present after a delay, pup the pop with a completion block and then in the completion block call present, as well as other ideas.
I think I am over complicating the whole thing, i believe their should be an easy way to do this.
Thanks for any help with this.
CLARIFICATION:
I do this on a touch:
if let vc = UIStoryboard(name: "Listing", bundle: nil).instantiateInitialViewController() as? ListingViewController
{
vc.listing = listing
vc.editListing = forEdit
vc.title = " "
self.navigationController?.pushViewController(vc, animated: true)
}
From that VC when the user touches a button I do this:
self.navigationController?.popViewController(animated: true)
When the VC goes away I want to do something like this:
if let vc = UIStoryboard(name: "CreateListing", bundle: nil).instantiateInitialViewController() as? NewCreateListingViewController
{
vc.bMakeSimiliar = makeSimiliar
vc.listing = listing
vc.editListing = editListing
vc.title = " "
self.navigationController?.pushViewController(vc, animated: true)
}
Basically my user is viewing the first controller which is a listing, from the listing VC he touches a button to add a new listing, so I want to dismiss the listing view controller and present him with the create listing view controller.
When I execute the above code to present the new VC nothing happens. I am doing this immediately after the popViewController.
You don't use pop to present next controller in stack. Pop actually navigates back from the current controller.
To perform what you're trying to achieve you need to call navigationController.pushViewController(viewController: UIViewController, animated: Bool) method.
In order to get back to some previous view controller you use:
navigationController.popViewController(animated: Bool)
In order to get to the root view controller you use:
navigationController.popToRootViewController(animated: Bool)
In order to get to some specific view controller in the stack you use:
popToViewController(viewController: UIViewController, animated: Bool)
I have a UILabel in my ViewController that has a NavigationController (let's say view controller A) with a tap gesture recognizer attached to the label. When the label is tapped another view appears (let's call it B). The user picks some text in B and the view dismisses back to A with the label text updated with the selection. So I created a delegation between A and B to get the selection. The problem is that I do not see the NavigationBar when B appears. Is there a way to fix this?
ViewController A
#IBOutlet weak var sectionName: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
let sectionLabelTap = UITapGestureRecognizer(target: self, action: #selector(labelTapped(_:)))
sectionName.isUserInteractionEnabled = true
sectionName.addGestureRecognizer(sectionLabelTap)
}
#objc func labelTapped(_ sender: UITapGestureRecognizer) {
let sectionNameVC = storyboard?.instantiateViewController(withIdentifier: "SectionName") as! SectionNameTableViewController
sectionNameVC.selectionNameDelegate = self
sectionNameVC.userData = userData
present(sectionNameVC, animated: true, completion: nil)
}
In order to display the Navigation bar the UIViewController needs to have a UINavigationController.
You can add that sectionNameVC ViewController into a UINavigationController to persevere the present animation.
In that case your code might look something like this:
#objc func labelTapped(_ sender: UITapGestureRecognizer) {
let sectionNameVC = storyboard?.instantiateViewController(withIdentifier: "SectionName") as! SectionNameTableViewController
sectionNameVC.selectionNameDelegate = self
sectionNameVC.userData = userData
let naviagtionController = UINavigationController(rootViewController: sectionNameVC)
present(naviagtionController, animated: true, completion: nil)
}
Or you can simply call pushViewController on the View Controller A's navigation Controller, like this:
self.navigationController?.pushViewController(sectionNameVC, animated: true)
This will add sectionNameVC into the View Controller A's navigation Controller stack. In this case the transition animation will be different, the sectionNameVC will come from your right.
You are missing the concept between "Presenting" View Controller & "Navigating" the View Controller. You will get the answer, once you understood the concept. Here, it is..
When you are presenting the ViewController, you are completely replacing the stack container to the new view controller.
STACK holds the addresses of the ViewControllers you push or pop via navigating.
e.g:
present(sectionNameVC, animated: true, completion: nil)
On the other hand, if you are navigating to other view controller by pushing it. In this case, you can go back to previous controller by simple popping the ViewController address from stack.
e.g:
self.navigationController?.pushViewController(sectionNameVC, animated: true)
self.navigationController?.popViewController(animated: true)
So, If you navigate then, only you will get navigation Bar.
Now, in your case, you are presenting the ViewController and hence, navigation bar is not showing.