用 CAShapeLayer 添加阴影？

Question

我有一个 CAShapeLayer 只有底部圆角。我想要的是在底部添加一个阴影，但它不起作用，即使代码看起来显然是正确的。它所做的一切都是围绕底角，但我没有看到阴影。

let shapeLayer = CAShapeLayer()

    let path = UIBezierPath(roundedRect: self.bounds, byRoundingCorners: [.bottomLeft, .bottomRight], cornerRadii: CGSize(width: 20, height: 20)).cgPath
    shapeLayer.path = path

    shapeLayer.shadowColor = UIColor(r: 233, g: 233, b: 233).cgColor
    shapeLayer.shadowOffset = CGSize(width: 0.0, height: 2.8)
    shapeLayer.shadowOpacity = 1.0
    shapeLayer.shadowRadius = 0.0
    shapeLayer.shouldRasterize = true
    shapeLayer.rasterizationScale = UIScreen.main.scale

    layer.rasterizationScale = UIScreen.main.scale
    layer.mask = shapeLayer

Answer 1

shapeLayer 将视图的角变圆，因为它被设置为图层的蒙版。您可能想将其添加为子图层。

旧：

layer.mask = shapeLayer

新：

layer.addSublayer(shapeLayer)

如果有帮助，我在这里写了另一个关于向圆角视图添加阴影的答案：

Answer 2

另一个解决方案，

以下 UIView 扩展将适用于您用来遮盖视图的任何形状

extension UIView {

  func addShadow() {
     self.backgroundColor = UIColor.clear
     let roundedShapeLayer = CAShapeLayer()
     let roundedMaskPath = UIBezierPath(roundedRect: self.bounds,
                                       byRoundingCorners: [.topLeft, .bottomLeft, .bottomRight],
                                       cornerRadii: CGSize(width: 8, height: 8))

     roundedShapeLayer.frame = self.bounds
     roundedShapeLayer.fillColor = UIColor.white.cgColor
     roundedShapeLayer.path = roundedMaskPath.cgPath

     self.layer.insertSublayer(roundedShapeLayer, at: 0)

     self.layer.shadowOpacity = 0.4
     self.layer.shadowOffset = CGSize(width: -0.1, height: 4)
     self.layer.shadowRadius = 3
     self.layer.shadowColor = UIColor.lightGray.cgColor
   }
}

用 CAShapeLayer 添加阴影？

Add a shadow with CAShapeLayer?

calayer

ios