Swift || Bug when Animating and Removing Subview from Superview - ios

Question

Im made and DropDown Menu to select Action like the GIF below.
Therefore I made a Subview and animated it in.
When animating the Subview out, it looks really weird.
In particular the problem is that it just looks like a blank small bar and not like the Menu.
Does anyone know where the problem might be?
The ViewController I'm making the Subview of is a simple ViewController with a TableView inside and 1 prototype cell.
Code:
let blackView = UIView()
var tvx: OptionsVC = OptionsVC()
var h: CGFloat!
.
func optionsClicked() {
self.h = CGFloat(70 + (52 * (OptionsVC().arrayFunctionCellNames.count)))
navigationController?.hidesBarsOnTap = false
tvx = self.storyboard?.instantiateViewController(withIdentifier: "options") as! OptionsVC
if let window = UIApplication.shared.keyWindow {
blackView.backgroundColor = UIColor(white: 0, alpha: 0.5)
blackView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleDismiss)))
view.addSubview(blackView)
view.addSubview(tvx.view)
let y = (self.navigationController?.navigationBar.frame.size.height)! + UIApplication.shared.statusBarFrame.height
tvx.view.frame = CGRect(x: 0, y: (y - self.h), width: view.frame.width, height: h)
blackView.frame = CGRect(x: 0, y: y, width: view.frame.width, height: view.frame.height)
blackView.alpha = 0
UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 1, options: .curveEaseOut, animations: {
self.blackView.alpha = 1
self.tvx.view.frame = CGRect(x: 0, y: y, width: self.view.frame.width, height: self.h)
self.blackView.frame = CGRect(x: 0, y: (y + self.h), width: self.view.frame.width, height: self.view.frame.height)
}, completion: nil)
}
}
.
func handleDismiss() {
UIView.animate(withDuration: 5.5, animations: {
let y = (self.navigationController?.navigationBar.frame.size.height)! + UIApplication.shared.statusBarFrame.height
self.blackView.alpha = 0
if let window = UIApplication.shared.keyWindow {
self.blackView.frame = CGRect(x: 0, y: y, width: self.view.frame.width, height: self.view.frame.height)
self.tvx.view.frame = CGRect(x: 0, y: (y - self.h), width: self.view.frame.width, height: self.h)
}
}, completion: {(finished:Bool) in
self.blackView.removeFromSuperview()
self.tvx.view.removeFromSuperview()
self.navigationController?.hidesBarsOnTap = true
})
}
GIF of BUG:
I made it so slow so you can better see it
Edit: My Solution
The problem was the constraints I set on my subview controller. Normally you set them to all sides, in my case, with was really weird I had to set them only to the bottom and sides. If I set some to the top, it would always do this bug.

Answer 1

You haven't really provided enough information for us to understand what's going on. What are tvx, blackView and self? What is the self.h variable? (From the animation it looks like you're changing the height of your "menu" view to be much shorter before you begin the animation code.)
Do you have a view controller contained inside another one using an embed segue?
If so, you should probably animate the constraints on the container view, not the child view controller's view.
As Glenn and D. Greg say in their comments, you should really be adding constraints to your views, hooking up outlets to those constraints, and animating changes to the constraint's constants rather than manipulating your view's frames directly. Animating changes to your view's frames isn't reliable when you're using AutoLayout, since AutoLayout can change your view's size and position out from under your animation code. That code looks like this, (in broad terms, no specific to your code)
myViewAConstraint.constant = someNewValue
myViewBConstraint.constant = someOtherValue
UIView.animate(withDuration: 5.5,
animations: {
someView.alpha = 0 //If you want the view to fade as it animates
self.view.layoutIfNeeded()
},
completion: { (finished:Bool) in
}
)