I have two test controllers: TestController1 and TestController2. I'm trying to deinit first controller when second controller loaded or appeared by changing UIApplication.shared.window[0].rootViewController to self (TestController2). But nothing is going on and I also have two controllers in memory. So, my question is: how can I deinit all ViewControllers and keeps in memory only one?
All my test controllers have deinit method and I'm trying to print "deinited" when it's executed, so i don't have any problems with break points like in many questions asked here.
This is my TestController2's code:
class TestController2: UIViewController {
deinit {
print("testController 2 deinited")
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
//first attempt
let del = UIApplication.shared.delegate as! AppDelegate
del.window?.rootViewController = self
//second attempt
UIApplication.shared.windows[0].rootViewController = self
//third attempt
UIApplication.shared.keyWindow?.rootViewController = self
}
}
All my attempts don't work..
Updated: First and second controllers have only one button. No any business logic. I created a segue by ctrl+drag mode on Storyboard from button at controller 1 to controller 2.
Related
Is there any equivalent in Swift to RACObserve(self, presentingViewController)?
Or any other why to imitate this behaviour?
My issue is that I want to be notified whenever a view controller is "hidden" by another view controller. In objc what I'd do is to check if self.presentingViewController is nil.
Note that in this scenario there's no knowledge of which view controller is presented, so it's impossible to notify from within its viewDidAppear/viewDidDisappear.
As I understand your question: you need to to know which view controller is presented now and you need notification inviewDidAppear/viewDidDisappear.
So we can get this in several way.
The simple way is:
Get information of which is the top ViewController right now.
2.Call this method in your viewDidAppear/viewDidDisappear
Like this :
Get Which is The Top ViewController
func getTopViewController() -> UIViewController? {
if var topVC = UIApplication.shared.keyWindow?.rootViewController {
while let presentedViewController = topVC.presentedViewController {
topVC = presentedViewController
return topVC
}
return topVC
}
return nil
}
Call in viewDidAppear:
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(true)
if let top = getTopViewController() {
print("topView Controller name \(top.title)")
top.view.backgroundColor = .red
}
}
Hope it will help you !
I am making a game, where I go from the main screen to a ArcadeViewController, which loads up the SKScene, and save the previous VC as prevVC.
I use segues created in storyboard to move between VC.
The problem is that each time I move to a VC, instead of moving into the old one, a copy gets created, and both of them start to run at the same time.
I tried removing them by running the following codes, when I move into the VC:
override func viewDidAppear(_ animated: Bool) {
UIApplication.shared.keyWindow?.rootViewController = self
self.view.window?.rootViewController?.dismiss(animated: true, completion: nil)
prevVC.reloadViewFromnib()
prevVC.dismiss(animated: false, completion: nil)
UserDefaults.standard.set(0, forKey: "since_The_Last_Ad")
}
extension UIViewController {
func reloadViewFromnib() {
let parent = view.superview
view.removeFromSuperview()
view = nil
parent?.addSubview(view) // This line causes the view to be reloaded
}
}
It helped to reduce the number of copies created, but still the are some.
How can I remove duplicate views?
So the solution ended up being to use the normal segue to launch the ArcadeVC from GameVC(start VC) for the first time.
Then set the ArcadeVC as rootVC:
UIApplication.shared.keyWindow?.rootViewController = self
Then use a normal segue to go back to the GameVC.
After the ArcadeVC is set as the rootVC, just use normal segue to the ArcadeVC form GameVC, and unwind from GameVC to AracdeVC.
Basically for this simple game app I have 2 different UIViewControllers called ViewController and PreviewController. PreviewController is opening view with the title screen and a label titled "Start game". When the label is tapped, it initiates a modal view controller (the ViewController class that has all the views for the actual game itself) and calls the "EnterNewGame" method from ViewController that sets up the game. Right now the issue I have is when calling this method, only part of the method seems to be running.
Here is the function in PreviewController that is being initiated upon tap:
#objc func handleButtonTap(_ recognizer: UITapGestureRecognizer) {
self.present(ViewController(), animated: true, completion: {() -> Void in
ViewController().enterNewGame()
})
}
And here is the EnterNewGame() method from ViewController
func enterNewGame() {
//show suit indicators when starting a new game
bluePlayerSuitsHidden = false
redPlayerSuitsHidden = false
game.blueTurn = true
self.setBackground()
self.cleanUpBoard()
self.createBoard()
self.displayBoard()
self.setSuitIndicators()
self.highlightCards()
playButton.isEnabled = false
}
Right now, when the label is tapped the screen transitions to the modal view controller but only displays a black screen with only one of the game setups (setting a few images on the top of the screen) working properly. I am sure that the EnterNewGame method works properly to actually start the game because I have tested it in isolation, so I think I am just not setting up the modal view controller properly or I have to call the method differently. Any help is appreciated, thanks.
Controller on which you're calling your method ins't the same instance as controller which you're presenting, you need constant (also your code can be simplified by avoiding using self references and writing name of completion parameter with specifing closure's parameter and return type)
#objc func handleButtonTap(_ recognizer: UITapGestureRecognizer) {
let controller = ViewController()
present(controller, animated: true) {
controller.enterNewGame()
}
}
Also, you can call this method on some other method inside your certain controller like viewDidLoad, viewWillAppear or you can create factory method which would return you certain set controller.
This last part leads me to idea: look how you instantiate your controller and look carefully if you don't need to instantiate it through storyboard or nib file.
class ViewController: UIViewController {
class func instantiate() -> ViewController {
let controller = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "Identifier") as! ViewController
// let controller = ViewController(nibName: "ViewController", bundle: nil)
controller.enterNewGame()
return controller
}
}
Usage:
#objc func handleButtonTap(_ recognizer: UITapGestureRecognizer) {
present(ViewController.instantiate(), animated: true)
}
assuming I have a viewcontroller (vcA) that pushes QRCodeScannerViewcontroller (vcB). When (vcB) scanned something, It will push ResultviewController (vcC).
-Those 3 views is connected to a UInavigation controller
-the user clicks on the back button on (vcC)
my question is:
1)how can I know if (vcB) is visible without changing code on (vcB)? (vcB) is a pod
2)where will I put this code? I can only access (vcA)
i tried adding this code on (vcA) but nothing happened
override func viewDidDisappear(_ animated: Bool) {
if (vcB.isViewLoaded && (vcB.view.window != nil)){
print("vcb did appear!")
}
}
To know if an instance of cvB's class exists in the navigation stack, you could use this piece of code:
let result = self.navigationController?.viewControllers.filter({
if let vcB = $0 as? UIViewController { // Replace UIViewController with your class, for example ViewControllerB
return true
}
return false
})
if result.isEmpty {
print("An instance of vcB's class hasn't been pused before")
} else {
print("An instance of vcB's class has been pused before")
}
What is the best way to pass a UInavigationController and also pass variables to a new viewController. I know how to do one or the other but not both at the same time. Thank you in advance
this is my current code
func(){
let vc = storyboard?.instantiateViewControllerWithIdentifier("messagesViewController") as! UINavigationController
let posts = self.postList[indexPath.row]
//this is the var that i want to past
//vc.previousViewMessageId = posts.postKey
self.presentViewController(vc, animated: true, completion: nil)
}
If I understand you correctly, you have a view controller that can present a second VC. And this VC is embedded in a UINavigationController. What you don't know how to do, is to pass data from the first VC, to the navigation controller, then to the second VC.
Here is a brute force solution. It's not beautiful, but it works anyway.
Make your own UINavigationController subclass:
class DataPasserController: UINavigationController {
var previousViewMessageId: SomeType?
override func viewDidLoad() {
if let vc = self.topViewController as? YourSecondViewController {
vc.previousViewMessageId = self.previousViewMessageId
}
}
}
Now you can add a navigation controller in the storyboard, set its class to DataPasserController, and connect the second VC to it as its root view controller.
Now suppose you have got an instance of DataPasserController by calling instantiateViewControllerWithIdentifier, you can do this:
yourDataPasserControllerInstance.previousViewMessageId = posts.postKey
And present the instance!
To pass a value to your Navigation Controller's Root View Controller, you access viewControllers[0] and cast it to the class of your Messages View Controller (the controller that has the previousViewMessageId property):
func () {
let messagesNC = storyboard?.instantiateViewControllerWithIdentifier("messagesViewController") as! UINavigationController
let messagesVC = messagesNC.viewControllers.first as! MessagesViewController
messagesVC.previousViewMessageId = postList[indexPath.row].postKey
presentViewController(messagesNC, animated: true, completion: nil)
}
What you have there is simply presenting a view controller... You are skipping the navigation controller.
What you need to do is present the new view controller inside the navigation controller. Once you have done that, it will show correctly. You can also pass the variables after you've created the vc variable.
This presents the new viewController (vc) within the navigation controller...
self.navigationController?.pushViewController(vc, animated: false)
This sets the variable in the new viewController (vc) (you are correct)
vc.previousViewMessageId = posts.postKey
So complete:
func(){
let vc = storyboard?.instantiateViewControllerWithIdentifier("messagesViewController") as! MessagesViewController
let posts = self.postList[indexPath.row]
//this is the var that i want to past
vc.previousViewMessageId = posts.postKey
navigationController?.pushViewController(vc, animated: false)
}
PS. While not part of the question, I feel I should still mention... Use of the word self should be left to necessity only. In other words, don't use it when it isn't needed. for example self.postList[indexPath.row] :)
https://github.com/raywenderlich/swift-style-guide#use-of-self