Changing to another View Controller after the launch screen animation in swift - ios

Question

I am new to iOS Development and I want to build some workout app and want to have some zoom-in animation after launching the app. I searched for it on the internet and found some YouTube video, where I saw how to do the animation immediately after launching the app. So I wrote down the code, that was presented in the video. So in the ViewController.swift I got imageView variable, which is the logo. And in ViewController.swift my code looks like this:
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(imageView)
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
imageView.center = view.center
DispatchQueue.main.asyncAfter(deadline: .now() + 0.5, execute: {self.animate()} )
}
private func animate() {
UIView.animate(withDuration: 1, animations: {
let size = self.view.frame.size.width * 1.82
let diffX = size - self.view.frame.size.width
let diffY = self.view.frame.size.height - size
self.imageView.frame = CGRect(
x: -(diffX/2),
y: diffY/2,
width: size,
height: size ) })
UIView.animate(withDuration: 1.9, animations: {
self.imageView.alpha = 0 }, completion: {done in
if done {
DispatchQueue.main.asyncAfter(deadline: .now() + 1, execute: {
let viewController = HomeViewController()
viewController.modalTransitionStyle = .crossDissolve
viewController.modalPresentationStyle = .fullScreen
self.present(viewController, animated: true)
})
}
})
}
And as I understand, it will load the HomeViewController, where I programmatically added a label "Hello!" in the center. And then I run the app, the logo zooms in and the screen changes to "Hello!".
But if I create a View Controller in Storyboard and link it to HomeViewController and also add there some label, it will not show in the app when I run it, even if I connect the ViewController Storyboard to HomeViewController by dragging it.
And for testing purposes I just created a second ViewController and called it SecondViewController (swift file, as well as a ViewController in the Storyboard, and linked it to the swift file), so I connected the HomeViewController to SecondViewController and in the Storyboard I added some Label to SecondViewController to see, if it going to be presented. But after launching the app, it did not present it.
And it throws a Warning in the Console like "Attempt to present SecondViewController on HomeViewController (from HomeViewController) whose view is not in the window hierarchy.
Attempt to present HomeViewController on ViewController (from ViewController) whose view is not in the window hierarchy.
How can I fix this and work later through the storyboard, design views, add buttons and so on?

Answer 1

welcome to stackOverflow. The problem is that you are not grabbing the correct instance of HomeViewController. By doing let viewController = HomeViewController() you are creating a new one rather than grabbing the instance you created in the storyboard.
Change that line to
let storyboard = UIStoryboard(name: "yourStoryboardName", bundle: nil)
let homeVC = storyboard.instantiateViewController(withIdentifier: "ViewControllerIdentifier") as! HomeViewController //set the VC's identifier from the storyboard identity inspector