Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
final class TransitionAnimator: NSObject, UIViewControllerAnimatedTransitioning {
// 1
let presenting: Bool
// 2
init(presenting: Bool) {
self.presenting = presenting
}
func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
// 3
return TimeInterval(UINavigationControllerHideShowBarDuration)
}
func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
// 4
guard let fromView = transitionContext.view(forKey: .from) else { return }
guard let toView = transitionContext.view(forKey: .to) else { return }
// 5
let duration = transitionDuration(using: transitionContext)
// 6
let container = transitionContext.containerView
if presenting {
container.addSubview(toView)
} else {
container.insertSubview(toView, belowSubview: fromView)
}
// 7
let toViewFrame = toView.frame
toView.frame = CGRect(x: presenting ? toView.frame.width : -toView.frame.width, y: toView.frame.origin.y, width: toView.frame.width, height: toView.frame.height)
let animations = {
UIView.addKeyframe(withRelativeStartTime: 0.0, relativeDuration: 0.5) {
toView.alpha = 1
if self.presenting {
fromView.alpha = 0
}
}
UIView.addKeyframe(withRelativeStartTime: 0.0, relativeDuration: 1) {
toView.frame = toViewFrame
fromView.frame = CGRect(x: self.presenting ? -fromView.frame.width : fromView.frame.width, y: fromView.frame.origin.y, width: fromView.frame.width, height: fromView.frame.height)
if !self.presenting {
fromView.alpha = 0
}
}
}
UIView.animateKeyframes(withDuration: duration,
delay: 0,
options: .calculationModeCubic,
animations: animations,
completion: { finished in
// 8
container.addSubview(toView)
transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
})
}
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.