ios - UIButton的左边框

为了绕过aUIButton的左下角，我取了code from this answer并修改了行：borderLayer.strokeColor = GenerateShape.UIColorFromHex(0x989898, alpha: (1.0-0.3)).CGColorb/c它不起作用。
但是，UIButton的左边框不是圆形的。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);
    }
}

最佳答案

成立：

self.layer.addSublayer(borderLayer)

例子：

self.layer.mask = borderLayer

关于ios - UIButton的左边框，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/48488540/