ios - Swift - 使用边框宽度和颜色设置标签边框有效，但在设置特定边时设置框架宽度关闭

Question

我试图在我的标签的某些边上加上边框，这样它们就不会重叠。这是我正在使用的代码:cell.jobAddress.layer.borderColor =

`cell.jobAddress.layer.borderColor = UIColor.black.cgColor
        cell.jobAddress.layer.borderWidth = 2
        cell.jobPlaceBid.layer.borderColor = UIColor.black.cgColor
        cell.jobPlaceBid.layer.borderWidth = 2
`

这是它的样子:

如您所见，底部和顶部重叠。所以，我一直在使用这段代码来尝试只在特定的边上添加边框:

    extension CALayer {

    func addBorder(edge: UIRectEdge, color: UIColor, thickness: CGFloat) {

        let border = CALayer()

        switch edge {
        case UIRectEdge.top:
            border.frame = CGRect(x: 0, y: 0, width: self.frame.width, height: thickness)
            break
        case UIRectEdge.bottom:
            border.frame = CGRect(x: 0, y: self.frame.height - thickness, width: self.frame.width, height: thickness)
            break
        case UIRectEdge.left:
            border.frame = CGRect(x: 0, y: 0, width: thickness, height: self.frame.height)
            break
        case UIRectEdge.right:
            border.frame = CGRect(x: self.frame.width - thickness, y: 0, width: thickness, height: self.frame.height)
            break
        default:
            break
        }

        border.backgroundColor = color.cgColor;

        self.addSublayer(border)
    }

}

然后这个来实现它:

cell.jobAddress.layer.addBorder(edge: UIRectEdge.left, color: UIColor.black, thickness: 2)
    cell.jobAddress.layer.addBorder(edge: UIRectEdge.right, color: UIColor.black, thickness: 2)
    cell.jobAddress.layer.addBorder(edge: UIRectEdge.top, color: UIColor.black, thickness: 2)
    cell.jobAddress.layer.addBorder(edge: UIRectEdge.bottom, color: UIColor.black, thickness: 2)
    cell.jobPlaceBid.layer.addBorder(edge: UIRectEdge.left, color: UIColor.black, thickness: 2)
    cell.jobPlaceBid.layer.addBorder(edge: UIRectEdge.right, color: UIColor.black, thickness: 2)
    cell.jobPlaceBid.layer.addBorder(edge: UIRectEdge.bottom, color: UIColor.black, thickness: 2)

这是它的样子:

您认为可能有什么问题？在添加边框之前，我一直等到标签有值。我只是通过使标签每边 10 点来设置宽度。

提前谢谢你，我知道这是一篇很长的文章!

Answer 1

在您调用 addBorder 时，自动布局还没有时间对您的 View 进行布局。

cell.setNeedsLayout()
cell.layoutIfNeeded()

强制计算 UILabel 尺寸，导致在 addBorder 方法中获得预期值。