ios - UIButton 的圆形左边框

Question

为了使 UIButton 的左下角变圆，我取了 code from this answer并修改了行:borderLayer.strokeColor = GenerateShape.UIColorFromHex(0x989898, alpha: (1.0-0.3)).CGColor b/c 它不起作用。

但是，UIButton 的左边框不是圆角的。如何修复？

代码

    button.frame = CGRect(x: 0, y: 0, width: 0.5*popUpView.frame.width, height: 0.25*popUpView.frame.height)
    button.layer.borderWidth = 3
    button.roundBtnCorners(roundedCorners, radius: cornerRadius)

extension UIButton{
    // Round specified corners of button
    func roundBtnCorners(_ corners:UIRectCorner, radius: CGFloat)
    {
        let borderLayer = CAShapeLayer()
        borderLayer.frame = self.layer.bounds
        borderLayer.strokeColor = UIColor(red: 168/266, green: 20/255, blue: 20/255, alpha: 0.7).cgColor
        borderLayer.fillColor = UIColor.clear.cgColor
        borderLayer.lineWidth = 1.0
        let path = UIBezierPath(roundedRect: self.bounds,
                                byRoundingCorners: corners,
                                cornerRadii: CGSize(width: radius, height: radius))
        borderLayer.path = path.cgPath
        self.layer.addSublayer(borderLayer);
    }
}

Answer 1

代替:

self.layer.addSublayer(borderLayer)

尝试:

self.layer.mask = borderLayer