如何在 draw(_:) 中为 UIBezierPath 设置动画？

Question

我的任务是在draw(_:) 方法中绘制矩形并为其高度设置动画。

var height = 0
override func draw(_ rect: CGRect) {
    let rect = CGRect(x: 0, y: 0, width: 100, height: height)
    let rectanglePath = UIBezierPath(rect: rect)
    UIColor.green.setFill()
    rectanglePath.fill()
}

我正在寻找这样的动画：

func animate() {
    UIView.animate(withDuration: 2) {
        self.height = 300
    }
}

我也可以使用CAShapeLayer和CABasicAnimation，但是我不知道如何在draw(_:)方法中绘制它。此任务需要使用draw(_:) 方法:(

Answer 1

class View: UIView{
override func draw(_ rect: CGRect)
{
    let rectanglePath = UIBezierPath(rect: self.frame)
    UIColor.green.setFill()
    rectanglePath.fill()
}}
class ViewController: UIViewController{

override func viewDidLoad()
{
    super.viewDidLoad()
    let subview = View(frame:  CGRect(x: 0, y: 0, width: 100, height: 0))
    self.view.addSubview(subview)

    UIViewPropertyAnimator.runningPropertyAnimator(
       withDuration: 2,
       delay: 0,
       options: .curveLinear,
       animations: {self.view.subviews[0].frame = CGRect(x: 0, y: 0, width: 100, height: 100)}
    )

}}