swift标签只剩下边框

Question

一起早上好，

我有这样的桌面视图：

示例：在单元格一中，我的右侧有一个红色文本标签。从它左边我包括一个像灰线的图像。

使用此代码，我可以设置一个完整的绿色边框：

    cell.Label.layer.borderWidth = 0.5
    cell.Label.layer.borderColor = UIColor.greenColor().CGColor

我可以在此文本标签的左侧仅设置边框吗？我使用swift ios8 - 所以，我需要一个快速的解决方案

Answer 1

这是您可以添加到项目中的扩展程序：

extension CALayer {

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

        var border = CALayer()

        switch edge {
        case UIRectEdge.Top:
            border.frame = CGRectMake(0, 0, CGRectGetHeight(self.frame), thickness)
            break
        case UIRectEdge.Bottom:
            border.frame = CGRectMake(0, CGRectGetHeight(self.frame) - thickness, UIScreen.mainScreen().bounds.width, thickness)
            break
        case UIRectEdge.Left:
            border.frame = CGRectMake(0, 0, thickness, CGRectGetHeight(self.frame))
            break
        case UIRectEdge.Right:
            border.frame = CGRectMake(CGRectGetWidth(self.frame) - thickness, 0, thickness, CGRectGetHeight(self.frame))
            break
        default:
            break
        }

        border.backgroundColor = color.CGColor;

        self.addSublayer(border)
    }

}

并使用它像这样：

cell.Label.layer.addBorder(UIRectEdge.Top, color: UIColor.greenColor(), thickness: 0.5)

Answer 2

Swift 3版本：

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)
    }

}

Answer 3

Swift 4版本：

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.bounds.width, height: thickness)

            case UIRectEdge.bottom:
             border.frame = CGRect(x: 0, y: self.bounds.height - thickness,  width: self.bounds.width, height: thickness)

            case UIRectEdge.left:
             border.frame = CGRect(x: 0, y: 0,  width: thickness, height: self.bounds.height)

            case UIRectEdge.right:
             border.frame = CGRect(x: self.bounds.width - thickness, y: 0,  width: thickness, height: self.bounds.height)

            default:
             break
        }
        border.backgroundColor = color.cgColor;
        self.addSublayer(border)
    }
}

Answer 4

除了使用扩展，您还可以使用@IBDesignable / @IBInspectable从UILabel创建子类并在那里绘制边框。这有一些优点，因为您可以使用Interface Builder来设置标签样式，并直接显示在Storyboard中。

@IBDesignable
class LeftBorderedLabel: UILabel {

    @IBInspectable var blockColor: UIColor = UIColor.black {

        didSet{

            let border = CALayer()
            border.frame = CGRect(x: 0, y: 0, width: 15, height: self.frame.height)
            border.backgroundColor = blockColor.cgColor;

            self.layer.addSublayer(border)
        }
    }

    override func prepareForInterfaceBuilder() {

        super.prepareForInterfaceBuilder()
    }
}

接口构建器中的示例（示例适用于uitableViewCell）：

Answer 5

这些解决方案对我有用，但我使用的是tableview行，行的高度是根据行中的内容动态设置的。

对于上述解决方案，我发现如果行的大小由于行内的内容而动态增加，则边框的大小不会增加。所以我的行边缘不完整，比正常大。

我在这个链接上发现了@Debaprio B的解决方案（2017年10月11日发布）：UIView set only side borders

他的解决方案对我有用，当我的行大小动态增加时，边框的大小发生了适当的变化。为简洁起见，我在下面分享@ Debaprio的答案：

---

public extension UIView {
// Border type and arbitrary tag values to identify UIView borders as subviews

public enum BorderType: Int {
case left = 20000
case right = 20001
case top = 20002
case bottom = 20003
}

public func addBorder(borderType: BorderType, width: CGFloat, color: UIColor {
// figure out frame and resizing based on border type
var autoresizingMask: UIViewAutoresizing
var layerFrame: CGRect

switch borderType {

case .left:
    layerFrame = CGRect(x: 0, y: 0, width: width, height: self.bounds.height)
    autoresizingMask = [ .flexibleHeight, .flexibleRightMargin ]
case .right:
    layerFrame = CGRect(x: self.bounds.width - width, y: 0, width: width, height: self.bounds.height)
    autoresizingMask = [ .flexibleHeight, .flexibleLeftMargin ]
case .top:
    layerFrame = CGRect(x: 0, y: 0, width: self.bounds.width, height: width)
    autoresizingMask = [ .flexibleWidth, .flexibleBottomMargin ]
case .bottom:
    layerFrame = CGRect(x: 0, y: self.bounds.height - width, width: self.bounds.width, height: width)
    autoresizingMask = [ .flexibleWidth, .flexibleTopMargin ]
}

// look for the existing border in subviews
var newView: UIView?
for eachSubview in self.subviews {
    if eachSubview.tag == borderType.rawValue {
        newView = eachSubview
        break
    }
}

Answer 6

这是您可以添加到项目中的扩展程序。

SWIFT 3： -

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:
            //For Center Line
            border.frame = CGRect(x: self.frame.width/2 - thickness, y: 0, width: thickness, height: self.frame.height)
            break
        }

        border.backgroundColor = color.cgColor;
        self.addSublayer(border)
    }
}

并使用它像这样：

labelName.layer.addBorder(edge: UIRectEdge.right, color: UIColor.black, thickness: 1.5)

如果要在Center上绘制一条线，则可以在任何场景中设置以下帧： -

border.frame = CGRect(x: self.frame.width/2 - thickness, y: 0, width: thickness, height: self.frame.height)