斯威夫特把阴影画成了一条uibezier路径

我有一个奇怪的问题.虽然我确实阅读了很多关于如何做到这一点的教程,但最终结果只显示了贝塞尔线,而不是任何阴影.我的代码非常简单：

let borderLine = UIBezierPath()
        borderLine.moveToPoint(CGPoint(x:0, y: y! - 1))
        borderLine.addLineToPoint(CGPoint(x: x!, y: y! - 1))
        borderLine.lineWidth = 2
        UIColor.blackColor().setStroke()
        borderLine.stroke()

        let shadowLayer = CAShapeLayer()
        shadowLayer.shadowOpacity = 1
        shadowLayer.shadowOffset = CGSize(width: 0,height: 1)
        shadowLayer.shadowColor = UIColor.redColor().CGColor
        shadowLayer.shadowRadius = 1
        shadowLayer.masksToBounds = false
        shadowLayer.shadowPath = borderLine.CGPath

        self.layer.addSublayer(shadowLayer)

我做错了什么,因为我似乎没有看到任何错误但当然我错了,因为没有阴影出现.函数是drawRect,基本的UIVIew没有任何额外的东西,x和y是框架的宽度和高度.提前谢谢了！

我直接从我的PaintCode应用程序中获取此示例.希望这可以帮助.

//// General Declarations
let context = UIGraphicsGetCurrentContext()


//// Shadow Declarations
let shadow = UIColor.blackColor()
let shadowOffset = CGSizeMake(3.1, 3.1)
let shadowBlurRadius: CGFloat = 5

//// Bezier 2 Drawing
var bezier2Path = UIBezierPath()
bezier2Path.moveToPoint(CGPointMake(30.5, 90.5))
bezier2Path.addLineToPoint(CGPointMake(115.5, 90.5))
CGContextSaveGState(context)
CGContextSetShadowWithColor(context, shadowOffset, shadowBlurRadius,  (shadow as UIColor).CGColor)
UIColor.blackColor().setStroke()
bezier2Path.lineWidth = 1
bezier2Path.stroke()
CGContextRestoreGState(context)