Swift changing button position doesn't work - ios

Question

I'm trying to change UIButton but it doesn't work. My code is like this.
#IBAction func addButtonTapped(_ sender: Any) {
print(defaultAddButton.center)
let buttonPos = CGPoint(x: defaultAddButton.frame.midX, y: defaultAddButton.frame.midY)
let width = self.view.bounds.width
let height: CGFloat = 100
let uiView = SubCollecionView(frame: CGRect(x: buttonPos.x - width / 2, y: buttonPos.y - height / 2, width: width, height: height))
self.view.addSubview(uiView)
self.defaultAddButton.center.y += 200
}
SubCollectionView is my custom view. Above code works without self.view.addSubview(uiView) line. I can't understand why it doesn't work. Thank you in advance!

Answer 1

do not fully understand your problem, but can suggest that you have a problem with animation, with this line of code:
self.defaultAddButton.center.y += 200
The above code doesn't work because you need to update the view to update its layout immediately, use this method to update view "layoutIfNeeded()"
Example of code:
class VC: UIViewController {
lazy var buttonAction: UIButton = {
let view = UIButton()
view.translatesAutoresizingMaskIntoConstraints = false
view.setTitle("Action", for: .normal)
view.setTitleColor(#colorLiteral(red: 1, green: 1, blue: 1, alpha: 1), for: .normal)
view.backgroundColor = .blue
view.addTarget(self, action: #selector(action(_:)), for: .touchUpInside)
return view
}()
#objc func action(_ sender: UIButton) {
print("action")
print(buttonAction.center)
let buttonPos = CGPoint(x: buttonAction.frame.midX, y: buttonAction.frame.midY)
let width = self.view.bounds.width
let height: CGFloat = 100
let uiView = MediaPlayer(frame: CGRect(x: buttonPos.x - width / 2, y: buttonPos.y - height / 2, width: width, height: height))
self.view.addSubview(uiView)
self.buttonAction.center.y += 200
UIView.animate(withDuration: 1.0) {
self.view.layoutIfNeeded()
}
}
func setupButton() {
self.view.addSubview(buttonAction)
buttonAction.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true
buttonAction.bottomAnchor.constraint(equalTo: self.view.bottomAnchor, constant: -70).isActive = true
buttonAction.heightAnchor.constraint(equalToConstant: 50).isActive = true
buttonAction.widthAnchor.constraint(equalToConstant: 100).isActive = true
}
override func viewDidLoad() {
super.viewDidLoad()
self.view.backgroundColor = .gray
setupButton()
}
}

Answer 2

You can try setting changes/frame in view over
viewDidLayoutSubviews

Answer 3

You should call layoutIfNeeded() after this.
#IBAction func addButtonTapped(_ sender: Any) {
print(defaultAddButton.center)
let buttonPos = CGPoint(x: defaultAddButton.frame.midX, y: defaultAddButton.frame.midY)
let width = self.view.bounds.width
let height: CGFloat = 100
let uiView = SubCollecionView(frame: CGRect(x: buttonPos.x - width / 2, y: buttonPos.y - height / 2, width: width, height: height))
self.view.addSubview(uiView)
self.defaultAddButton.center.y += 200
self.view.layoutIfNeeded()
}
If this doesn't work. Please try to call UI modification code inside the main queue.
#IBAction func addButtonTapped(_ sender: Any) {
print(defaultAddButton.center)
DispatchQueue.main.async {
let buttonPos = CGPoint(x: defaultAddButton.frame.midX, y: defaultAddButton.frame.midY)
let width = self.view.bounds.width
let height: CGFloat = 100
let uiView = SubCollecionView(frame: CGRect(x: buttonPos.x - width / 2, y: buttonPos.y - height / 2, width: width, height: height))
self.view.addSubview(uiView)
self.defaultAddButton.center.y += 200
self.view.layoutIfNeeded()
}
}