Simultaneous UIViewController Transition Animations - ios

Question

I am trying to fade-in a background gradient image and slide up a uiview card from the bottom (off-screen) to the center of the uiviewcontroller - executing both animations simultaneously when the uiviewcontroller is presented modally.
What I've attempted is to set the uiviewcontroller modal transition style to cross dissolve, which would provide the fade-in effect for the background gradient image, and in viewDidAppear run the animation to slide up the uiview card from the bottom to center.
While this works, there's a slight delay with the card, and ideally I hoped both animations took place at the same time.
Is this grouping possible? Any guidance would be appreciated.
Below is relevant code in the modally presented view controller:
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
alertViewCenterYConstraint.constant += view.bounds.height
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
UIView.animate(withDuration: 0.1, delay: 0, options: .curveEaseOut, animations: {
self.alertViewCenterYConstraint.constant = 0
self.view.layoutIfNeeded()
}, completion: nil)
}

Answer 1

This one works like a magic. I love it.
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
alertViewCenterYConstraint.constant += view.bounds.height
DispatchQueue.main.async {
UIView.animate(withDuration: 0.1, delay: 0.05, options: .curveEaseOut, animations: {
self.alertViewCenterYConstraint.constant = 0
self.view.layoutIfNeeded()
}, completion: nil)
}
}