最佳答案
您可以在 CAShapeLayer
上为 path
的笔划末端设置动画,例如,
weak var shapeLayer: CAShapeLayer?
@IBAction func didTapButton(_ sender: Any) {
// remove old shape layer if any
self.shapeLayer?.removeFromSuperlayer()
// create whatever path you want
let path = UIBezierPath()
path.move(to: CGPoint(x: 10, y: 50))
path.addLine(to: CGPoint(x: 200, y: 50))
path.addLine(to: CGPoint(x: 200, y: 240))
// create shape layer for that path
let shapeLayer = CAShapeLayer()
shapeLayer.fillColor = #colorLiteral(red: 0, green: 0, blue: 0, alpha: 0).cgColor
shapeLayer.strokeColor = #colorLiteral(red: 1, green: 0, blue: 0, alpha: 1).cgColor
shapeLayer.lineWidth = 4
shapeLayer.path = path.cgPath
// animate it
view.layer.addSublayer(shapeLayer)
let animation = CABasicAnimation(keyPath: "strokeEnd")
animation.fromValue = 0
animation.duration = 2
shapeLayer.add(animation, forKey: "MyAnimation")
// save shape layer
self.shapeLayer = shapeLayer
}
产生:
显然,您可以将 UIBezierPath
更改为您感兴趣的任何内容。例如,路径中可以有空格。或者您甚至不需要直线路径:
let path = UIBezierPath()
path.move(to: CGPoint(x: 10, y: 130))
path.addCurve(to: CGPoint(x: 210, y: 200), controlPoint1: CGPoint(x: 50, y: -100), controlPoint2: CGPoint(x: 100, y: 350))
您还可以在 CAAnimationGroup
中组合笔划开始和结束的动画:
// create shape layer for that path (this defines what the path looks like when the animation is done)
let shapeLayer = CAShapeLayer()
shapeLayer.fillColor = #colorLiteral(red: 0, green: 0, blue: 0, alpha: 0).cgColor
shapeLayer.strokeColor = #colorLiteral(red: 1, green: 0, blue: 0, alpha: 1).cgColor
shapeLayer.lineWidth = 5
shapeLayer.path = path.cgPath
shapeLayer.strokeStart = 0.8
let startAnimation = CABasicAnimation(keyPath: "strokeStart")
startAnimation.fromValue = 0
startAnimation.toValue = 0.8
let endAnimation = CABasicAnimation(keyPath: "strokeEnd")
endAnimation.fromValue = 0.2
endAnimation.toValue = 1.0
let animation = CAAnimationGroup()
animation.animations = [startAnimation, endAnimation]
animation.duration = 2
shapeLayer.add(animation, forKey: "MyAnimation")
产量:
CoreAnimation 使您可以对描边路径的渲染方式进行大量控制。
关于swift - 画线动画,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/42978418/