I have my GameViewController that contains a SCNView. I can segue to my GameViewController but when my player dies I try to segue to my GameOverVC but it does not segue. I know the code is being called because I print something to the console. The segue is setup in the storyboard.
I segue by calling
self.performSegue(withIdentifier: "gameOver", sender: self)
I have done this in multiple apps but I can not figure out why this is not working. This is my first app with SceneKit so I don't know if that changes anything but any help is appreciated!
Also
If I try
let vc = self.view.window?.rootViewController
vc?.present(GameOverVC(), animated: true, completion: nil)
Then it does present the UIViewController but it does not show anything I have added in that view?
Somehow I had the same problem and asynchronous-call rescue me:
I did something like this:
DispatchQueue.main.asyncAfter(deadline: .now()) {
self.performSegue(withIdentifier: "gameOver", sender: self)
}
if you need to segue from an object that is not a ViewController inherited class, you need to pass a ref of the parentViewController to your object and make the call like this:
DispatchQueue.main.asyncAfter(deadline: .now()) {
parentViewController.performSegue(withIdentifier: "gameOver", sender: self)
}
segue works for UIVIewControllers not for SpriteKit scenes. So, you need to perform segue from parent viewcontroller, so you can do something like,
self.parentViewController.performSegue(withIdentifier: "gameOver", sender: self)
Or as mentioned by #ZeMoon in this answer, you can make property of your viewcontroller in SKScene class and you can perform segue over this property something like ,
class GameScene: SKScene {
var viewController: UIViewController?
...
}
Then, in the viewController class, just before skView.presentScene(scene) do,
scene.viewController = self
Now you can perform segue like,
self.viewController.performSegueWithIdentifier("gameOver", sender: self.viewController)
OR
Forget segue just instantiate your GameOverVC and push it on your navigation controller like,
let nav = self.view.window?.rootViewController as! UINavigationController
nav.pushViewController(gameOverVC, animated: true)
Or
self.navigationController?.pushViewController(gameOverVC, animated: true)
You can try following :-
UIViewController *vc = self.view.window.rootViewController;
[vc performSegueWithIdentifier:#"id" sender:nil];
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.
Suppose I have three view controllers in a Main.storyboard. Two of the three, vc_login and vc_studyDesc load the other view controller using a UIButton with 'present modally' option.
The other one vc_signup has a UIButton, which may go back to the previous controller. To implement this, I used the following methods:
vc_studyDesc has an identifier of studyDesc; I let it pass its identifier to vc_signup. In the same way, vc_login has login as an identifier.
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if sender as! UIButton == qnaSignUp {
let signup = segue.destinationViewController as! vc_signup
signup.latestVC = "studyDesc"}}
This one is in the UIViewController class for vc_signup. By referencing a string latestVC, the method determines which VC to move on.
#IBAction func backBtnClick(sender: UIButton) {
print("latestVS: \(latestVC)")
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier(latestVC)
vc.modalTransitionStyle = UIModalTransitionStyle.CrossDissolve
print("check check")
self.presentViewController(vc, animated: true, completion: nil)}
The problem I have is that the app gets terminated when vc_studyDesc is called by vc_signup. I found that this is because I missed a significant variable which must be loaded in vc_signup.
vc_studyDesc has some data to be referenced from Firebase when it is loaded. I did this by loading a variable postID from the prior vc to vc_studyDesc; which is vc_list.
So I just saved postID using NSUserdefaults.standardUserDefaults(). It is solved but I'm wondering if there's any way to pass data using the way I used in vc_signup.
As far as I see, I cannot find any way to pass the data into vc_studyDesc.swift; for the vc is chosen by its identifier..
Can I pass the variable I want in the way I want?? And adding tags would be appreciated!
So there are a couple problems with this design.
When you instantiate a viewController you are creating a new instance of that class, and presenting it adds it to the stack. Think of the stack like a deck of cards, you start with one card and then add or remove them, the top card being the visible vc. When you are going back to studyDesc you are instantiating and presenting it so you will have 3 VCs in your stack, of which two are studyDesc (the one you started with and the one you add when you try to go back)
To remove a VC from the stack you can use
dismissViewController(animated: true, completion: nil)
or if you have the VCs in a navigation controller you can use
popViewControllerController(animated: true, completion: nil)
in terms of passing information between viewControllers, if the info is in the VC you use to present your new controller you can use prepareForSegue like you already have. To pass information back you should use a delegate pattern. So to implement a delegate pattern in this case you would do the following:
Declare a protocol (not inside your classes, above there but below your import's)
protocol SignUpDelegate {
signInCompleted(infoToPass: AnyObject)
}
Then have your studyDesc class conform to this protocol and implement the function signInCompleted
StudyDescVC: UIViewController, SignUpDelegate {
func signInCompleted(infoToPass: AnyObject) {
// do what you want with the info here
}
}
Then in your signUpVc add a var delegate (which will be used to call the signInCompeleted function)
class SignInVC: UIViewController {
var delegate: SignUpDelegate!
func finishedSigningIn() {
delegate.signInCompleted(infoToPass: //yourinfo)
self.dismissViewControllerAnimated(true, completion: nil)
}
And then in your prepareForSegue set the delegate
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if sender as! UIButton == qnaSignUp {
let signup = segue.destinationViewController as! vc_signup
signup.delegate = self
}
}
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier(latestVC) as! YOUR_VIEW_CONTROLLER_NAME
vc.modalTransitionStyle = UIModalTransitionStyle.CrossDissolve
vc.name = "Andrew"
print("check check")
self.presentViewController(vc, animated: true, completion: nil)
//set a variale or property to your viewController
class YOUR_VIEW_CONTROLLER_NAME: UIViewController {
var name: String?
}
I have the following storyboard: Main Storyboard
In it, several custom View Controllers are programmatically embedded in the Scroll View. In one of them, a button is present and should trigger a segue to show the "hey" screen.
I have then wrote the following code:
#IBAction func addNewDateButtonDidTouched(sender :AnyObject) {
let mainStoryboard = UIStoryboard(name: "Main", bundle: nil)
let storyboardInit = mainStoryboard.instantiateViewControllerWithIdentifier("mainview")
storyboardInit.performSegueWithIdentifier("showNewDate", sender: self)
}
This #IBAction seems to reload the inital view controller and perform the segue correclty (Xcode doesn't return any error). But the "hey" screen doesn't show up and its viewDidLoad() doesn't load.
Any hint?
Instead of calling
storyboardInit.performSegueWithIdentifier("showNewDate", sender: self)
try
self.performSegueWithIdentifier("showNewDate", sender: self)
The storyboardInit in your code will instantiate a UIViewController that has an identifier "mainview".
But this UIViewController hasn't been added to the screen, when you're asking the controller to perform a segue.
So, I wouldn't do that. What I would do, to segue to the hey screen is either :
Create a segue from the current controller and just do this in the code : self.performSegueWithIdentifier
Instantiate the hey controller like this : instantiateViewControllerWithIdentifier, and then just do the self.presentViewController
So, to transition to a new controller, you have to start from the current controller.
if i understand your viewcontroller hierarchy correctly...
since the viewcontroller that contains the button to trigger the segue is a childviewcontroller of the viewcontroller that has the segue setup in storyboard i think you have to call presentingViewController?.performSegueWithIdentifier("showNewDate", sender: self).
I have a following class:
class HomeViewController: UIViewController {
override func viewdidload() {
super.viewdidload()
callOtherVC()
}
func callOtherVC() {
let viewController = StepsViewController()
let rootViewController = UINavigationController(rootViewController: viewController)
self.presentViewController(rootViewController, animated: true, completion: nil)
}
}
StepsViewController is just another viewcontroller. In StepsViewController, I try to dismiss current StepsViewController and present other viewcontroller. Following is code.
class StepsViewController: UIViewController {
override func viewdidload() {
super.viewdidload()
callSecondOtherVC()
}
func callSecondOtherVC() {
let vc = ViewController()
self.addChildViewController(vc)
self.parentViewController!.dismissViewControllerAnimated(true, completion: nil)
vc.callOtherVC()
}
}
I initialize ViewController() because I need to call same function callOtherVC from ViewController. Basically the model in ViewController changes but I'm essentially calling same UINavigationController from callOtherVC function.
Whenever I do this, I get an error like below:\
Warning: Attempt to present (UINavigationController: 0x7d991600) on
(HomeViewController: 0x7a6e00a0) whose view is not in the window
hierarchy!
UINavigationController is from callSecondOtherVC and HomeViewController is as it is.
How should I order the VCs? And if someone can more explain about the view hierarchy, I would greatly appreciate.
I think what you need to do here, is call your method from viewDidAppear, rather than viewDidLoad. The reason for this is that the view is not in the view hierarchy at the time of viewDidLoad.
I have three View Controllers embedded in Navigation Controller. I want to go from VC1 to VC3 so that in VC3 the Navigation Item's back button would direct the user to VC2 instead of VC1. I think this should be done either by adding the VC2 to the Navigation Stack between VC1 and VC3 when VC3 is created or by skipping the second View Controller.
I tried this:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if let identifier = segue.identifier {
switch identifier {
case "JumpToThirdVCSegue":
if let secondvc = segue.destinationViewController as? SecondViewController {
secondvc.performSegueWithIdentifier("ThirdVCSegue", sender: self)
}
default: break
}
}
}
but I couldn't get it working. Perhaps performing a segue isn't possible when the View Controller isn't open yet?
What is the best way to skip a View Controller / add a View Controller in the middle of Navigation Stack? I hope this helps you to understand what I'm trying to do:
Something like this should work:
self.navigationController?.pushViewController(viewController2, animated: true)
self.navigationController?.pushViewController(viewController3, animated: true)
EDIT:
If you want to push the second view controller without being noticed by the user you need to add it to the navigation controller after the third view controller is pushed. This can be done by implementing UINavigationControllerDelegate. You can store your second view controller in a variable and insert it to the navigation controllers hierarchy in delegate method. Your main view controller will look like following:
class MyViewController: UIViewController, UINavigationControllerDelegate {
var viewControllerToInsertBelow : UIViewController?
override func viewDidLoad() {
super.viewDidLoad()
self.navigationController?.delegate = self
}
func pushTwoViewControllers() {
if let viewController2 = self.storyboard?.instantiateViewControllerWithIdentifier("id1"),
let viewController3 = self.storyboard?.instantiateViewControllerWithIdentifier("id2") { //change this to your identifiers
self.viewControllerToInsertBelow = viewController2
self.navigationController?.pushViewController(viewController3, animated: true)
}
}
//MARK: - UINavigationControllerDelegate
func navigationController(navigationController: UINavigationController, didShowViewController viewController: UIViewController, animated: Bool) {
if let vc = viewControllerToInsertBelow {
viewControllerToInsertBelow = nil
let index = navigationController.viewControllers.indexOf(viewController)!
navigationController.viewControllers.insert(vc, atIndex: index)
}
}
}
if var navstack = navigationController?.viewControllers{
navstack.append(contentsOf: [vc1,vc2])
navigationController?.setViewControllers(navstack, animated: true)
}
Works well
Edit: using swift and segues, this should work:
override func performSegueWithIdentifier(identifier: String?, sender: AnyObject?) {
super.performSegueWithIdentifier(identifier, sender: sender);
if identifier == "JumpToThirdVCSegue" {
// now the vc3 was already pushed on the navigationStack
var navStackArray : [AnyObject]! = self.navigationController!.viewControllers
// insert vc2 at second last position
navStackArray.insert(viewController2, atIndex: navStackArray.count - 2)
// update navigationController viewControllers
self.navigationController!.setViewControllers(navStackArray, animated:false)
}
}
So you override the performSegueWithIdentifier in the VC1 in order to change the navigation stack when the segue to VC3 has actually been performed (and is not only in preparation).
This assumes, that you want to handle this special navigation logic in VC1.
You can use method
func setViewControllers(_ viewControllers: [UIViewController],
animated: Bool)
Here's the documentation (link) that solves the UIViewController skipping problem.
Simply pass all the needed UIViewControllers to it (in navigational order) and the last one will be made as the current active UIViewController (if it already isn't the active one).
My solution would be to keep a BOOL property of when you should skip to third and when not skip, like declaring ’shouldSkip’ in VC2 so that if u set it in prepare segue like below you can act according to that in VC2
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if let identifier = segue.identifier {
switch identifier {
case "JumpToThirdVCSegue":
secondvc.shouldSkip=true
}
default: break
}
}
}
and then in viewDidload VC2 you should check this BOOL and if it is true and perform segue and if not just move on
you could also pass pass whenever that kind of skip is not necessary
Building off of MarkHim's answer, I was getting a Black screen when navigating back to the inserted view controller so I came up with the following solution.
BTW - I wanted to insert the new view controller directly under the view controller I just segued to hence the navStack.count - 1 instead of navStack - 2.
Here is my solution:
override func performSegue(withIdentifier identifier: String, sender: Any?) {
super.performSegue(withIdentifier: identifier, sender: sender)
if identifier == "JumpToThirdViewControllerSegue",
let navController = navigationController { // unwrap optional
// initialize the view controller you want to insert
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let viewControllerToInsert = storyboard.instantiateViewController(
withIdentifier: "SecondVC") as! SecondViewController
// set any passed properties
viewControllerToInsert.passedProperty = propertyToPass
// create an object using the current navigation stack
var navStackArray: [UIViewController]! = navController.viewControllers
// insert the newly initialized view controller into the navStackArray
navStackArray.insert(viewControllerToInsert, at: navStackArray.count - 1)
// replace the current navigation stack with the one you just
// inserted your view controller in to
navController.setViewControllers(navStackArray, animated: false)
}
}