What I want to achieve: segue from gameVC to mainmenuVC and get rid of the gameVC
When the app starts it first shows a main menu viewcontroller with a play button that segues to the gameviewcontroller. When the user taps on a menu button sprite the following function in the gameviewcontroller gets called and it segues back to the main menu:
func returnToMainMenu () {
//This works but does not deinit the vc
navController?.dismissViewControllerAnimated(true, completion: nil)
/* this does not do anything:
navController?.popViewControllerAnimated(true)
*/
}
This is probably not how it is done properly and I think that might be the problem, but I could not get to work otherwise because gameViewController.navigationViewController is nil.
This is how my storyboard looks:
This is how the memory usage looks when the app is running. Those spikes/steps occur whenever the gameviewcontroller is loaded. It seems to me that the problem is, that the gameviewcontroller does not de-initialize when returnToMainMenu() is called.
Also, this never gets executed:
deinit {
debugPrintln("GameViewController deinitialized")
}
update:
I deleted this
navController = self
and defined navController in returnToMainMenu like this:
let navController = view.window?.rootViewController as! UINavigationController
segue back to main menu still works but it still does not deinit the vc
Of course it will memory leak.
override func viewDidLoad() {
navController = self
}
You just gave yourself a reference to itself. Usually when your vc goes offscreen, the view hierarchy no longer holds the view so the view is deinited. You set a reference to itself so whatever you do, it will always hold itself in memory and will never deinit.
I figured it out after watching Lecture 8 of the stanford iOS8 course (at 14:23).
The problem was that I added a reference to the gameviewcontroller in my gamescene to call its returnToMainMenu() method from the scene. In order for its memory to be cleared all the references to the VC have to be set to nil.
I solved it by referring to the navigation controller directly from my scene like this:
(scene!.view!.window?.rootViewController as! UINavigationController).dismissViewControllerAnimated(false, completion: nil)
Related
I'm coding a simple app with swift and I'm stuck at the following point, I have two Controllers that lead to another one, and when I click on the cancel button, it always lead to the root Controller, no matter from where I come.
I have a first controller (UIViewController), that go to the Navigation Controller of my target Controller (the one from which I would like to go back to the right calling Controller).
I have a second controller (UITableViewController), which go directly to my target Controller.
Here's the code of my Cancel button:
// MARK: - Navigation
#IBAction func lendingCancelButton(_ sender: UIBarButtonItem) {
// Depending on style of presentation (modal or push presentation), this view controller needs to be dismissed in two different ways
let isPresentingInAddLendingMode = presentingViewController is UINavigationController
if isPresentingInAddLendingMode {
dismiss(animated: true, completion: nil)
} else if let owningNavigationController = navigationController {
owningNavigationController.popViewController(animated: true)
} else {
fatalError("the LendingViewController is not inside a navigation controller.")
}
}
If I correctly understood (you could then correct me if I'm wrong, I would learn something), it's testing if the ViewController that's presenting my target ViewController is a NavigationController.
So maybe that, as the second Controller (my UITableViewController) is not going through a NavigationController, so the last one calling my target view with a NavigationController is always the UIViewController.
Don't hesitate to tell me if it's not clear enough (too many times the word "Controller" in my post) or if you need additional code.
Try something like this
if let navigationController = presentingViewController as UINavigationController {
navigationController.popViewController(animated: true)
} else if let viewController = presentingViewController as UIViewController {
dismiss(animated: true, completion: nil)
} else {
fatalError("the LendingViewController is not inside a navigation controller.")
}
If i understood you want to use dismiss when you find a UIViewController and to pop the navigation when you find a UINavigationController right?
Ok so I finally found a way to make it working.
My tableViewController was embedded into a NavigationController. I removed it (since I could do without it, according to my need). From this View Controller, I draw a segue that "Show" my target view.
From my other ViewController (this one is embedded into a NavigationController), I draw a segue put that present modally my target view.
With the code provided in my initial post, it's working.
The only thing I didn't understand is why the NavigationController from my TableViewController was likely to cause it not working properly.
I have a viewcontroller embedded in a navigationcontroller that pushes another viewcontroller onto the stack. This pushed viewcontroller has an embedded viewcontroller that segues/modally presents a final viewcontroller.
On a button click, I am trying to dismiss the final presented viewcontroller and pop the present-ing viewcontroller and return to the initial state.
Thus far, I've been able to get the dismiss going, but popping does not seem to work in the completion handler of the dismiss.
I've tried printing out the hierarchy, i.e. self.presentingViewController, self.navigationController, self.presentingViewController.presentingViewController..., all of which output nil, and am admittedly stuck now on returning to the initial state.
In looking at the view hierarchy, the final presented viewcontroller is beneath a UITransitionView separate from the rest of the stack I had mentioned earlier..
Any thoughts/guidance would be appreciated.
Since you mentioned segues I think unwind segues might help. I built a quick test project and they do indeed function correctly in your scenario.
There is a rather excellent answer in a related SO question What are Unwind segues for and how do you use them?. A summary of the answer for your particular case is: place the following function in your initial view controller:
#IBAction func unwindToThisViewController(segue: UIStoryboardSegue)
{
}
You can then directly 'unwind' to that viewcontroller by using Storyboard Segues directly (as in the referenced answer) or programatically via:
self.performSegue(withIdentifier: "unwindToThisViewController", sender: self)
Again there's a good article entitled Working with Unwind Segues Programmatically in Swift which goes into lots of detail.
Can you try
if let nav = UIApplication.shared.keyWindow?.rootViewController as? UINavigationController {
self.dismiss(animated:true) {
nav.popToRootViewController(animated:true)
}
}
Following Apple's documentation for adding and editing information Apple guide here I have a Viewcontroller with a tableview. The tableview contains a header with a "Add new" Button. If a table row is selected the detailViewController is pushed onto the stack. The detailViewController is also embedded in a UINavigationController, as in Apple's docs. If "Add new" is pressed, another segue is performed which presents the UINavigationController modally, which in turns shows the detailViewController. This works fine and the animation clearly shows a modally presented ViewController.
The detailViewController contains a Cancel Button in the NavigationBar. If it is pressed the following code is run:
#IBAction func cancel(_ sender: UIBarButtonItem) {
// Depending on style of presentation (modal or push presentation), this view controller needs to be dismissed in two different ways.
var isPresentingInAddActionMode = false
if let presentingVC = self.presentingViewController{
isPresentingInAddActionMode = presentingVC is UINavigationController
}
streekgidsModel.undoManager.endUndoGrouping()
print("undo grouping ended and undone")
streekgidsModel.undoManager.undo()
if isPresentingInAddActionMode {
dismiss(animated: true, completion: nil)
}
else if let owningNavigationController = navigationController{
owningNavigationController.popViewController(animated: true)
}
else {
fatalError("The MealViewController is not inside a navigation controller.")
}
}
The first if-statement checks if the property presentingViewController is present, and if so if it is of type UINavigationController. If so, the viewController is presented modally and should be dismissed. If not it is pushed onto the stack and the owningNavigationController should pop the detailViewController.
Running this code does not work as described by Apple. The check on the presentingViewController shows it is present, but the type check gives back "invalid". This is treated as false. The test on the owningNavigationController succeeds (I think it should fail) and the popViewController is executed. As there was no push, the view controller is not popped or dismissed and is still visible. A second press on Cancel executes the func cancel again, which results in an error as there is no longer a group started in the undo manager.
Baffling thing is that I have the same code in another viewcontroller, with similar UIViewTable and navigation and it works fine.
So to frame the question: why does this not work the way Apple describes it, why does my other view controller work as it is supposed to? Any input is appreciated.
BTW, the fatal error text is straight from the docs so the naming is not relevant and it is never executed.
I would start with checking who is presenter.
According to Apple docs on this:
When you present a view controller modally (either explicitly or implicitly) using the present(_:animated:completion:) method, the view controller that was presented has this property set to the view controller that presented it. If the view controller was not presented modally, but one of its ancestors was, this property contains the view controller that presented the ancestor. If neither the current view controller or any of its ancestors were presented modally, the value in this property is nil.
If the docs are correct then your presenter should be your "Viewcontroller with a tableview" which, I guess, is not UINavigationController. If that is the case then you should understand why your code fails.
It depends on your context of course, but I would just simplify a check this way:
var isPresentingInAddActionMode = self.presentingViewController != nil
... // your other code
if isPresentingInAddActionMode {
dismiss(animated: true, completion: nil)
}
else if let owningNavigationController = navigationController{
owningNavigationController.popViewController(animated: true)
}
If I understood your question and intent correctly then it doesn't matter for you who (which class) presented your detailVC and you care only about how your detailVC was presented - either pushed in navigation view controller or presented modally. I think just by checking presentingViewController property you can get that information.
Hello I have code set up that should correctly segue from GameScene to another view controller, mainMenuViewController. The code I have set up to achieve this is
var viewController: GameViewController!
func segue() {
viewController.dismissViewControllerAnimated(true, completion: nil)
SettingsViewController.delete(self)
}
In GameViewController
class GameViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let skView = view as! SKView
let scene = GameScene(size: skView.bounds.size)
skView.showsFPS = true
skView.showsNodeCount = true
skView.ignoresSiblingOrder = false
//skView.showsPhysics = true
scene.scaleMode = .AspectFill
skView.presentScene(scene)
scene.viewController = self
}
}
which is called when a SKLabelNode is tapped. I received advice to use this since the mainMenu is the scene that is first loaded when the player starts the game and they segue to gameScene so I was told to dismiss GameScene instead of creating a new segue every time. I get the error 'fatal error: unexpectedly found nil while unwrapping an Optional value' and a crash whenever the button is tapped. I assume it is talking about the viewController. Thank you for your help!
If understand correctly your problem, you are trying to dismiss GameViewController. But method dismissViewControllerAnimated only dismisses controller that you are currently presenting. So as your game view controller is not presenting anything it can't dismiss it. As you say from code to GameViewController dismiss controller that was presented by him, it tries to do as you want so he gets his property of presented view controller and try to dismiss it, but that property is nil so such error gets. To fix this problem you should call viewController.presentingViewController.dismissViewControllerAnimated(true, completion: nil) .
Property presentingViewController returns controller that presents you, in your case controller that present GameViewController. As you get this controller you can dismiss controller that was presented by him(in you case presented controller is your GameViewController). So logic is to get as to say "parent" controller that has permissions to dismiss yourself(GameViewController)
I need to look to your code. It seams now that you try to call method delete to view controller, but as I know view controller doesn't have such. So think that is other bug in your program, and mainly you are setting Noble_Ninja.SettingsViewController to other object that expect to have such method. That is my prediction I can't say anything clearly because i only has exception description. Try to find where you calling this method in your code , than put brakepoints there and when program stops on your brakepoint write in your console(log) - (po NAME_OF_INSTANCE_THAT_CALLS_SUCH_METHOD) -, it will show real instance type, so with this info you can detect where is real problem. Good luck
I'm presenting a modal view controller using a custom transition (by setting its modelPresentationStyle to UIModalPresentationCustom, providing a transitioning delegate, and UIViewControllerAnimatedTransitioning object).
In the presented view controller, I have an unwind segue hooked up to a button. The segue fires just fine; the IBAction method in the presenting view controller is called, and so is prepareForSegue in the presented view controller. However, the presented view controller is not dismissed, and the appropriate transitioning delegate method (animationControllerForDismissedController:) is not called.
If, however, I set the presented view controller's modalPresentationStyle to UIModalPresentationFullScreen (the default), the view controller is dismissed properly (this breaks my custom transition, though).
I'm at a complete loss at what to do here. I've looked through Apple's documentation, and didn't notice anything saying that one had to do special things with unwind segues when dealing with custom transitions.
I'm aware that I could call dismissViewControllerAnimated:completion: in the IBAction method of the presenting view controller, but I'd rather use that as a last resort, and get the unwind segue working the way it should (or at least know why it's not working :) ).
Any help would be much appreciated,
Thanks in advance
It seems that if you use UIModalPresentationCustom to present the controller with a custom transition manager, you also need to use a custom transition manager to dismiss it (which makes sense I guess, since you can do all kinds of weird stuff in the animator object and UIKit can't be sure that just dismissing the screen as usual will completely restore the original state - I just wish it told you that explicitly...).
Here's what I've done to fix this in my app:
override segueForUnwindingToViewController in the parent view controller (the one to which you're moving after the dismiss animation) and return an instance of your UIStoryboardSegue, either the one you've used for the original transition or a new separate class
if the unwind segue's target view controller is in a navigation hierarchy, then you need to override that method in the navigation controller instead
in the perform method call dismissViewControllerAnimated
the presented view controller needs to still hold a valid reference to the transitioning delegate, or you'll get an EXC_BAD_ACCESS (see DismissViewControllerAnimated EXC_Bad_ACCESS on true) - so either make it keep the delegate as a strong reference as described in that thread, or assign a new one before calling dismissViewControllerAnimated (it's possible that changing modelPresentationStyle to e.g. full screen before dismissing would work too, but I haven't tried that)
if the dismiss animation needs to do any non-standard things (mine luckily didn't), override animationControllerForDismissedController in the transition manager object and return a proper animator
if the target view controller is in a navigation hierarchy, then you also need to manually pop the navigation stack to the target controller before dismissing the presented screen (i.e. target.navigationController!.popToViewController(target, animated: false))
Complete code sample:
// custom navigation controller
override func segueForUnwindingToViewController(toViewController: UIViewController,
fromViewController: UIViewController,
identifier: String?) -> UIStoryboardSegue {
return CustomSegue(
identifier: identifier,
source: fromViewController,
destination: toViewController
)
}
// presented VC
var customTransitionManager: UIViewControllerTransitioningDelegate?
// custom segue
override func perform() {
let source = sourceViewController as! UIViewController
if let target = destinationViewController as? PresentedViewController {
let transitionManager = TransitionManager()
target.modalPresentationStyle = .Custom
target.customTransitionManager = transitionManager
target.transitioningDelegate = transitionManager
source.presentViewController(target, animated: true, completion: nil)
} else if let target = destinationViewController as? WelcomeViewController {
target.navigationController!.popToViewController(target, animated: false)
target.dismissViewControllerAnimated(true, completion: nil)
} else {
NSLog("Error: segue executed with unexpected view controllers")
}
}
I also met this problem when I need to pass data back from the modalpresented view.
I wandering around Google and here for a couple of hours but I couldn't find an answer that is easy to understand for me. But I did get some hint and here's a work around.
It seems that because it has to pass data back, and the dismissing process from the automatic Unwind is prior before the data passing which prevented the ViewController being dismissed. So I think that I have to manually dismiss it once one more time.
I got some luck here. I didn't notice that it was a child viewcontroller. I just configured it from the storyboard.
And then in the Unwind function, I added to lines to remove the child viewcontroller and the child view. I have no code in the sourceViewController.
Swift 4.1
#IBAction func unwindToVC(sender :UIStoryboardSegue){
if let source = sender.source as? CoreLocationVC{
if source.pinnedCity != nil{
clCity = source.pinnedCity
}
if source.pinnedCountry != nil {
clCountry = source.pinnedCountry
}
if source.pinnedTimeZone != nil {
clTimeZone = source.pinnedTimeZone
}
if source.pinnedLocation != nil {
clLocation = source.pinnedLocation
}
// I added 2 lines here and it just worked
source.view.removeFromSuperview()
source.removeFromParentViewController()
}