Question

我正在尝试动画2 UIViews，UIView1存在，按下按钮，UIView2从右向左滑动并占据屏幕，将UIView1移开。

我可以使用slideLeftTransitionFromView成功实现这一部分。但是，再次按下按钮可以用slideRightTransitionFromView从左到右滑动UIView1，UIView1在动画过程中会以某种方式消失。 UIView2从左到右成功滑动，但我看不到UIView1。

我确信slideRightTransitionFromView遵循与slideLeftTransitionFromView类似的逻辑，但我无法让它发挥作用。

这是两个功能：

func slideLeftTransitionFromView(view: UIView, toView: UIView, duration: NSTimeInterval, completion: ((Bool) -> Void)?)
{
    if let container = view.superview
    {
        // Final position of outgoing view
        let outgoingViewEndX = view.frame.origin.x - view.frame.size.width

        // Final position of incoming view (existing frame)
        let incomingViewEndX = view.frame.origin.x

        // Start point of incoming view -- at the right edge of the outgoing view
        let incomingViewStartX = view.frame.origin.x + view.frame.size.width

        // Distance traveled by outgoing view
        let outgoingDisplacement = view.frame.origin.x - outgoingViewEndX

        toView.frame.origin = CGPointMake(incomingViewStartX, toView.frame.origin.y)
        container.addSubview(toView)

        dispatch_async(dispatch_get_main_queue(), { ()
            UIView.animateWithDuration(duration, delay: 0, options: .CurveLinear, animations: {

                view.frame.origin.x = outgoingViewEndX
                toView.frame.origin.x = incomingViewEndX

                }, completion: {(complete: Bool) in

                    // If the outgoing view is still in onscreen, keep sliding until it's offscreen
                    if outgoingViewEndX + view.frame.size.width > 0 {

                        // Adjust the duration for the final animation based on the distance it has to travel in order to keep the same velocity.
                        let finalDuration = duration * Double((outgoingViewEndX + view.frame.size.width)/outgoingDisplacement)

                        UIView.animateWithDuration(finalDuration, delay: 0, options: .CurveLinear, animations: {

                            view.frame.origin.x = -view.frame.size.width
                            }, completion: { (complete: Bool) in
                                completion?(complete)
                                view.removeFromSuperview()
                        })
                    }
                    else
                    {
                        completion?(complete)
                        view.removeFromSuperview()
                    }
            })
        })
    }
}

func slideRightTransitionFromView(view: UIView, toView: UIView, duration: NSTimeInterval, completion: ((Bool) -> Void)?)
{
    if let container = view.superview
    {
        // Final position of outgoing view
        let outgoingViewEndX = view.frame.origin.x + view.frame.size.width

        // Final position of incoming view (existing frame)
        let incomingViewEndX = view.frame.origin.x

        // Start point of incoming view -- at the left edge of the outgoing view
        let incomingViewStartX = view.frame.origin.x - view.frame.size.width

        // Distance traveled by outgoing view
        let outgoingDisplacement = view.frame.origin.x + outgoingViewEndX

        toView.frame.origin = CGPointMake(incomingViewStartX, toView.frame.origin.y)
        container.addSubview(toView)

        dispatch_async(dispatch_get_main_queue(), { ()
            UIView.animateWithDuration(duration, delay: 0, options: .CurveLinear, animations: {

                view.frame.origin.x = outgoingViewEndX
                toView.frame.origin.x = incomingViewEndX

                }, completion: {(complete: Bool) in

                    // If the outgoing view is still in onscreen, keep sliding until it's offscreen
                    if outgoingViewEndX + view.frame.size.width < 0 {

                        // Adjust the duration for the final animation based on the distance it has to travel in order to keep the same velocity.
                        let finalDuration = duration * Double((outgoingViewEndX + view.frame.size.width)/outgoingDisplacement)

                        UIView.animateWithDuration(finalDuration, delay: 0, options: .CurveLinear, animations: {

                            view.frame.origin.x = view.frame.size.width
                            }, completion: { (complete: Bool) in
                                completion?(complete)
                                view.removeFromSuperview()
                        })
                    }
                    else
                    {
                        completion?(complete)
                        view.removeFromSuperview()
                    }
            })
        })
    }
}

这可能很简单，但我看不到它。什么似乎是问题？

由于

Answer 1

您可能已将UIView IBOutlet声明为弱变量

slideLeftTransitionFromView中的

调用view.removeFromSuperview()会从视图heirarchy中移除视图，并且我非常确定您的视图已被解除分配，因为它是一个弱变量而不再是布局的一部分。

因此，当您尝试将其再次添加为子视图时，您不会看到它稍后的。尝试使用var强引用。

UIView幻灯片动画从左到右出现问题？

1 个答案: