我有什么
我正在使用带有附加UIViewPropertyAnimator的UIViewControllerAnimatedTransitioningprotocol向下平移以关闭视图控制器
extension SecondViewController : UIViewControllerAnimatedTransitioning {
func interruptibleAnimator(using ctx: UIViewControllerContextTransitioning) -> UIViewImplicitlyAnimating {
if self.animator != nil {
return self.animator!
}
let containerView = ctx.containerView
let toVC = ctx.viewController(forKey: .to) as! FirstViewController
let fromVC = ctx.viewController(forKey: .from) as! SecondViewController
containerView.insertSubview(toVC.view, belowSubview: fromVC.view)
self.animator = UIViewPropertyAnimator(duration: transitionDuration(using: ctx),
curve: .easeOut, animations: {
self.fromVC.view.transform = CGAffineTransform(scale: 0.5)
})
self.animator.isInterruptible = true
self.animator.isUserInteractionEnabled = true
self.animator.isManualHitTestingEnabled = true
self.animator.addCompletion { position in
switch position {
case .end:
break
case .current:
break
case .start:
break
}
let cancelled = ctx.transitionWasCancelled
if (cancelled) {
//..
} else {
//..
}
ctx.completeTransition(!cancelled)
}
self.animator = anim
return self.animator
}
func transitionDuration(using ctx: UIViewControllerContextTransitioning?) -> TimeInterval {
return 0.5
}
func animateTransition(using ctx: UIViewControllerContextTransitioning) {
let animator = self.interruptibleAnimator(using: ctx)
self.animator.startAnimation()
}
func animationEnded(_ transitionCompleted: Bool) {
self.interactiveTransition = nil
self.animator = nil
}
}
用于处理动画的平移手势：
func handlePanGesture(gestureRecognizer: UIPanGestureRecognizer) {
let panTranslation = gestureRecognizer.translation(in: gestureRecognizer.view!)
var progress = panTranslation.y / (gestureRecognizer.view!.bounds.size.height * 0.5)
switch gestureRecognizer.state {
case .began:
self.interactiveTransition = UIPercentDrivenInteractiveTransition()
self.navigationController!.popViewController(animated: true)
case .changed:
self.interactiveTransition!.update(progress)
case .cancelled, .ended:
if progress > 0.5 {
//Complete Transition
let timingParameters = UICubicTimingParameters(animationCurve: .easeInOut)
self.animator!.continueAnimation!(withTimingParameters: timingParameters, durationFactor: progress)
self.animator?.addAnimations! {
//Completion Animations
}
self.interactiveTransition!.finish()
} else {
//Cancel Transition
self.animator!.isReversed = true
let timingParameters = UICubicTimingParameters(animationCurve: .easeInOut)
self.animator!.continueAnimation!(withTimingParameters: timingParameters, durationFactor: progress)
self.animator!.addAnimations!({
//Cancelling Animations
}, delayFactor: 0 )
self.interactiveTransition!.cancel()
}
default:
break
}
}
什么有效
向下滑动到解雇效果很好。 稍微向下滑动并抬起手指取消也可以完美地工作。
问题
向下轻扫和向上轻扫超过起点(进度变为负数(并抬起手指应该会取消带有取消动画的过渡。 这在iOS 10中发生，但它首先反转导航控制器转换，然后回弹。 在iOS 11中，取消动画发生，然后我看到导航控制器过渡被反转。 如果您等待，您可以看到导航控制器过渡确实尝试在 10 分钟左右的动画中自行更正。
问题：
- self.interactiveTransition!.cancel()?
- self.interactiveTransition!.completionSpeed ??
我不知道这是一个错误还是我们都做错了，但要纠正行为，请在平移手势处理程序.ended情况下向interactionController添加.completionSpeed = 0.999。这是一个黑客，但至少它只是一行。