ios 使用 Swift 动画视图高度
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Animate view height with Swift
提问by moonvader
I have view sViewinside my ViewController. It height has constraint - I created IBOutlet for this constraint - sViewHeightConstraint. I want to decrease height of sView with animation.
我的 ViewController 中有视图sView。它的高度有约束 - 我为此约束创建了 IBOutlet - sViewHeightConstraint。我想用动画降低 sView 的高度。
I created function
我创建了函数
UIView.animateWithDuration(5.5, animations: {
self.sViewHeightConstraint.constant = 50
})
Height of view is changing but i don't see any animation. What I am doing wrong?
视图高度在变化，但我没有看到任何动画。我做错了什么？
回答by EI Captain v2.0
use layoutIfNeeded()
用 layoutIfNeeded()
view.layoutIfNeeded() // force any pending operations to finish
UIView.animateWithDuration(0.2, animations: { () -> Void in
self.sViewHeightConstraint.constant = 50
self.view.layoutIfNeeded()
})
swift 3
迅捷 3
view.layoutIfNeeded()
sViewHeightConstraint.constant = 50
UIView.animate(withDuration: 1.0, animations: {
self.view.layoutIfNeeded()
})
