swift

  let myView = UIView()
    
//UIBezierPath的构造函数参数

    let maskPath = UIBezierPath(roundedRect: myView.bounds, byRoundingCorners: [UIRectCorner.topRight, UIRectCorner.topLeft], cornerRadii: CGSize(width: 8, height: 8))

      let maskLayer = CAShapeLayer()

      maskLayer.frame = myView.bounds

      maskLayer.path = maskPath.cgPath

      myView.layer.mask = maskLayer

      view.addSubview(myView)