导航控制器，pushViewController 的转场动画 ios

与 ViewController 的 present 转场动画不同
1, 导航控制器，pushViewController 的转场动画，的代理是

navigationController?.delegate = self

【导航控制器，pushViewController 的转场动画】2, 指定动画的方法

extension Two: UINavigationControllerDelegate{func navigationController(_ navigationController: UINavigationController, animationControllerFor operation: UINavigationController.Operation, from fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? { if operation == .push{ return navAnimatorPush } else{ return nil } }}

具体的动画设置也不同
使用 snapshotView , 会出现奇怪的效果
代码很好理解

class NavBaseCustomAnimatorPush: NSObject, UIViewControllerAnimatedTransitioning{func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval { return 1 }func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {guard let fromCtrl = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.from), let toCtrl = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.to), let fromView = fromCtrl.view, let toView = toCtrl.view else{ return }let containerView = transitionContext.containerView let f = UIScreen.main.boundsfromView.frame = fcontainerView.addSubview(fromView) containerView.addSubview(toView)toView.frame = presentingDirection.offsetF(withFrame: f)UIView.animate(withDuration: transitionDuration(using: transitionContext), delay: 0.0, usingSpringWithDamping: 0.5, initialSpringVelocity: 0.0, options: .curveLinear) { toView.frame = f } completion: { _ in let success = !transitionContext.transitionWasCancelled transitionContext.completeTransition(success) } }}

github repo