要制作一个打开的条形动画...
@IBOutlet var barHeight: NSLayoutConstraint!
barHeight.constant = barShut?30:100
self.view.layoutIfNeeded()
t = !barShut?30:100
UIView.animate(withDuration: 0.15,
delay: 0,
options: UIViewAnimationOptions.curveEaseOut,
animations: { () -> Void in
self.barHeight.constant = t
self.view.layoutIfNeeded()
},
completion: {_ in
Screen.barShut = !Screen.barShut
}
)
太棒了...
但是你该如何让它像这样弹跳?
我唯一知道的方法是使用CADisplayLink和几行代码来实现弹簧衰减效果。这个方法在UIKit中可用吗?
constant
属性,具体请参考我的回答。 - Paulw11