Question

我想在navigationController的推送和弹出中制作过渡动画。但它真的很奇怪。就像1/ fromViewController淡出它应该淡出但toViewController不会淡入，它就会出现。限制条件有时候也很奇怪。如果我使用标准转换，一切都OK。这是我的过渡课程：

class TMFadeAnimator: NSObject, UIViewControllerAnimatedTransitioning {

    func transitionDuration(transitionContext: UIViewControllerContextTransitioning?) -> NSTimeInterval {
        return 0.5
    }

    func animateTransition(transitionContext: UIViewControllerContextTransitioning) {

        let toViewController   = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey)
        let fromViewController   = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey)
        toViewController?.beginAppearanceTransition(true, animated: true)
        fromViewController?.beginAppearanceTransition(false, animated: true)

        transitionContext.containerView()!.addSubview(toViewController!.view)


        toViewController!.view.alpha = 0.0

        UIView.animateWithDuration(self.transitionDuration(transitionContext), animations: {
            toViewController!.view.alpha = 1.0
            fromViewController!.view.alpha = 0.0
        }) { (finished) in
            toViewController?.endAppearanceTransition()
            fromViewController?.endAppearanceTransition()
            transitionContext.completeTransition(finished)
        }
    }
}

Answer 1

奇怪的是，在定义toViewController?.view.frame = fromViewController!.view.frame和toViewController之后放置fromViewController来解决问题。（感谢A＆＃39;狄更斯发现它）。这是最终的代码

class TMFadeAnimator: NSObject, UIViewControllerAnimatedTransitioning {

    func transitionDuration(transitionContext: UIViewControllerContextTransitioning?) -> NSTimeInterval {
        return 0.5
    }

    func animateTransition(transitionContext: UIViewControllerContextTransitioning) {

        let toViewController   = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey)
        let fromViewController   = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey)

        toViewController?.view.frame = fromViewController!.view.frame

        toViewController?.beginAppearanceTransition(true, animated: true)
        fromViewController?.beginAppearanceTransition(false, animated: true)

        transitionContext.containerView()!.addSubview(toViewController!.view)


        toViewController!.view.alpha = 0.0

        UIView.animateWithDuration(self.transitionDuration(transitionContext), animations: {
            toViewController!.view.alpha = 1.0
            fromViewController!.view.alpha = 0.0
        }) { (finished) in
            toViewController?.endAppearanceTransition()
            fromViewController?.endAppearanceTransition()
            transitionContext.completeTransition(finished)
        }
    }
}

UIViewControllerAnimatedTransitioning无法正常工作

1 个答案: