UIView.animation问题
UIView.animation问题
提问于 2017-11-02 21:03:22
UIView动画问题:动画完成后，有另一个动画关闭，在视图上滑动，但在视图上留下一些线条，如何解决？
let frameHeight: CGFloat = 44.0
self.frame = CGRect(x: 0, y: -frameHeight, width: UIScreen.main.bounds.width, height: frameHeight)
UIView.animate(withDuration: 0.5, animations: {
self.frame.origin.y += self.frameHeight
}, completion: { _ in
UIView.animate(withDuration: 0.5, delay: 1, options: [], animations: {
self.frame.origin.y -= self.frameHeight
})
})回答 1
Stack Overflow用户
发布于 2017-11-02 21:16:58
在动画开始之前计算视图的帧，因为动画块不会在与外部块上下文相同的runloop中运行。
此外，我注意到您在本地定义另一个frameHeight时引用了动画块中的self.frameHeight属性。
尝试此操作(预计算原点Y)：
let frameHeight: CGFloat = 44.0
self.frame = CGRect(x: 0, y: -frameHeight, width: UIScreen.main.bounds.width, height: frameHeight)
// Calcuate destinations before
let finalOriginDestinationY = self.frame.origin.y
let firstOriginDestinationY = self.frame.origin.y + frameHeight
UIView.animate(withDuration: 0.5, animations: {
// Set absolute value - otherwise the frame is calculated according to position at current time
self.frame.origin.y = firstOriginDestinationY
}, completion: { _ in
UIView.animate(withDuration: 0.5, delay: 1, options: [], animations: {
// Set absolute value (Precalculated)
self.frame.origin.y = finalOriginDestinationY
})
})页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/47076066
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