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如何在UIView的顶部添加边框

iosobjective-cxcodeuiviewborder
168

我的问题是关于标题的。

我不知道如何在特定的一侧、顶部或底部添加边框，任意一侧... layer.border 会为整个视图绘制边框...

可能是UIView底部边框？的重复问题。 - Cœur
35个回答
217

我认为在这种情况下，继承UIView并覆盖drawRect是过度的。为什么不在UIView上添加扩展并添加边框子视图呢？

@discardableResult
func addBorders(edges: UIRectEdge,
                color: UIColor,
                inset: CGFloat = 0.0,
                thickness: CGFloat = 1.0) -> [UIView] {

    var borders = [UIView]()

    @discardableResult
    func addBorder(formats: String...) -> UIView {
        let border = UIView(frame: .zero)
        border.backgroundColor = color
        border.translatesAutoresizingMaskIntoConstraints = false
        addSubview(border)
        addConstraints(formats.flatMap {
            NSLayoutConstraint.constraints(withVisualFormat: $0,
                                           options: [],
                                           metrics: ["inset": inset, "thickness": thickness],
                                           views: ["border": border]) })
        borders.append(border)
        return border
    }


    if edges.contains(.top) || edges.contains(.all) {
        addBorder(formats: "V:|-0-[border(==thickness)]", "H:|-inset-[border]-inset-|")
    }

    if edges.contains(.bottom) || edges.contains(.all) {
        addBorder(formats: "V:[border(==thickness)]-0-|", "H:|-inset-[border]-inset-|")
    }

    if edges.contains(.left) || edges.contains(.all) {
        addBorder(formats: "V:|-inset-[border]-inset-|", "H:|-0-[border(==thickness)]")
    }

    if edges.contains(.right) || edges.contains(.all) {
        addBorder(formats: "V:|-inset-[border]-inset-|", "H:[border(==thickness)]-0-|")
    }

    return borders
}

    // Usage:         
    view.addBorder(edges: [.all]) // All with default arguments 
    view.addBorder(edges: [.top], color: .green) // Just Top, green, default thickness
    view.addBorder(edges: [.left, .right, .bottom], color: .red, thickness: 3) // All except Top, red, thickness 3

使用这段代码，你不仅可以将其应用于继承自UIView的任何对象上，而且还可以在你的项目和其他项目中重复使用。通过向方法传入其他参数来定义其他颜色和宽度。有许多选项。

4
唯一的缺点是它无法调整大小。 - Peter DeWeese
2
可以使用UIView并添加自动布局约束。同样的原理。 - Adam Waite
1
@PeterDeWeese 这也不是什么缺点 - 如果你想要控制边框的大小，你只需要这样做：
  • (void)addUpperBorderWithSize:(CGFloat)size 然后在函数中用参数替换常量即可。 其他参数如颜色也是同理。
 - o.shnn
1
@AdamWaite，这个自动布局变体看起来非常不错。谢谢！ - manonthemoon
2
感谢分享，我制作了一个带有自动布局约束的Objective-C版本在这里。 - Itachi
显示剩余9条评论
106

添加了圆角的功能原先由Adam Waite在他的原始帖子和多次编辑中实现。

重要提示：在调用“addborder”之前，请不要忘记添加“label.layoutIfNeeded()”，正如之前所注释的那样。

注意：我仅在UILabel上对此进行了测试。

extension CALayer {
    
    enum BorderSide {
        case top
        case right
        case bottom
        case left
        case notRight
        case notLeft
        case topAndBottom
        case all
    }
    
    enum Corner {
        case topLeft
        case topRight
        case bottomLeft
        case bottomRight
    }
    
    func addBorder(side: BorderSide, thickness: CGFloat, color: CGColor, maskedCorners: CACornerMask? = nil) {
        var topWidth = frame.size.width; var bottomWidth = topWidth
        var leftHeight = frame.size.height; var rightHeight = leftHeight
        
        var topXOffset: CGFloat = 0; var bottomXOffset: CGFloat = 0
        var leftYOffset: CGFloat = 0; var rightYOffset: CGFloat = 0
        
        // Draw the corners and set side offsets
        switch maskedCorners {
        case [.layerMinXMinYCorner, .layerMaxXMinYCorner]: // Top only
            addCorner(.topLeft, thickness: thickness, color: color)
            addCorner(.topRight, thickness: thickness, color: color)
            topWidth -= cornerRadius*2
            leftHeight -= cornerRadius; rightHeight -= cornerRadius
            topXOffset = cornerRadius; leftYOffset = cornerRadius; rightYOffset = cornerRadius
            
        case [.layerMinXMaxYCorner, .layerMaxXMaxYCorner]: // Bottom only
            addCorner(.bottomLeft, thickness: thickness, color: color)
            addCorner(.bottomRight, thickness: thickness, color: color)
            bottomWidth -= cornerRadius*2
            leftHeight -= cornerRadius; rightHeight -= cornerRadius
            bottomXOffset = cornerRadius
            
        case [.layerMinXMinYCorner, .layerMinXMaxYCorner]: // Left only
            addCorner(.topLeft, thickness: thickness, color: color)
            addCorner(.bottomLeft, thickness: thickness, color: color)
            topWidth -= cornerRadius; bottomWidth -= cornerRadius
            leftHeight -= cornerRadius*2
            leftYOffset = cornerRadius; topXOffset = cornerRadius; bottomXOffset = cornerRadius;
            
        case [.layerMaxXMinYCorner, .layerMaxXMaxYCorner]: // Right only
            addCorner(.topRight, thickness: thickness, color: color)
            addCorner(.bottomRight, thickness: thickness, color: color)
            topWidth -= cornerRadius; bottomWidth -= cornerRadius
            rightHeight -= cornerRadius*2
            rightYOffset = cornerRadius
            
        case [.layerMaxXMinYCorner, .layerMaxXMaxYCorner,  // All
              .layerMinXMaxYCorner, .layerMinXMinYCorner]:
            addCorner(.topLeft, thickness: thickness, color: color)
            addCorner(.topRight, thickness: thickness, color: color)
            addCorner(.bottomLeft, thickness: thickness, color: color)
            addCorner(.bottomRight, thickness: thickness, color: color)
            topWidth -= cornerRadius*2; bottomWidth -= cornerRadius*2
            topXOffset = cornerRadius; bottomXOffset = cornerRadius
            leftHeight -= cornerRadius*2; rightHeight -= cornerRadius*2
            leftYOffset = cornerRadius; rightYOffset = cornerRadius
            
        default: break
        }
        
        // Draw the sides
        switch side {
        case .top:
            addLine(x: topXOffset, y: 0, width: topWidth, height: thickness, color: color)
            
        case .right:
            addLine(x: frame.size.width - thickness, y: rightYOffset, width: thickness, height: rightHeight, color: color)
            
        case .bottom:
            addLine(x: bottomXOffset, y: frame.size.height - thickness, width: bottomWidth, height: thickness, color: color)
            
        case .left:
            addLine(x: 0, y: leftYOffset, width: thickness, height: leftHeight, color: color)

        // Multiple Sides
        case .notRight:
            addLine(x: topXOffset, y: 0, width: topWidth, height: thickness, color: color)
            addLine(x: 0, y: leftYOffset, width: thickness, height: leftHeight, color: color)
            addLine(x: bottomXOffset, y: frame.size.height - thickness, width: bottomWidth, height: thickness, color: color)

        case .notLeft:
            addLine(x: topXOffset, y: 0, width: topWidth, height: thickness, color: color)
            addLine(x: frame.size.width - thickness, y: rightYOffset, width: thickness, height: rightHeight, color: color)
            addLine(x: bottomXOffset, y: frame.size.height - thickness, width: bottomWidth, height: thickness, color: color)

        case .topAndBottom:
            addLine(x: topXOffset, y: 0, width: topWidth, height: thickness, color: color)
            addLine(x: bottomXOffset, y: frame.size.height - thickness, width: bottomWidth, height: thickness, color: color)

        case .all:
            addLine(x: topXOffset, y: 0, width: topWidth, height: thickness, color: color)
            addLine(x: frame.size.width - thickness, y: rightYOffset, width: thickness, height: rightHeight, color: color)
            addLine(x: bottomXOffset, y: frame.size.height - thickness, width: bottomWidth, height: thickness, color: color)
            addLine(x: 0, y: leftYOffset, width: thickness, height: leftHeight, color: color)
        }
    }
    
    private func addLine(x: CGFloat, y: CGFloat, width: CGFloat, height: CGFloat, color: CGColor) {
        let border = CALayer()
        border.frame = CGRect(x: x, y: y, width: width, height: height)
        border.backgroundColor = color
        addSublayer(border)
    }
    
    private func addCorner(_ corner: Corner, thickness: CGFloat, color: CGColor) {
        // Set default to top left
        let width = frame.size.width; let height = frame.size.height
        var x = cornerRadius
        var y = cornerRadius
        var startAngle: CGFloat = .pi; var endAngle: CGFloat = .pi*3/2
        
        switch corner {
        case .bottomLeft:
            y = height - cornerRadius 
            startAngle = .pi/2; endAngle = .pi
            
        case .bottomRight:
            x = width - cornerRadius
            y = height - cornerRadius
            startAngle = 0; endAngle = .pi/2
            
        case .topRight:
            x = width - cornerRadius
            startAngle = .pi*3/2; endAngle = 0
            
        default: break
        }
        
        let cornerPath = UIBezierPath(arcCenter: CGPoint(x: x, y: y),
                                      radius: cornerRadius - thickness,
                                      startAngle: startAngle,
                                      endAngle: endAngle,
                                      clockwise: true)

        let cornerShape = CAShapeLayer()
        cornerShape.path = cornerPath.cgPath
        cornerShape.lineWidth = thickness
        cornerShape.strokeColor = color
        cornerShape.fillColor = nil
        addSublayer(cornerShape)
    }
}
4
由于Swift 3对CGRectMake签名和CGColor进行了更改，因此这段代码不能在Swift 3上运行。请尝试修改相关内容以使其适用于Swift 3。 - EmbCoder
2
在 Swift 3 中实现成功了吗？ - user6553825
10
为了让它起作用，你需要在调用view.layer.addBorder(...)之前加上view.layoutIfNeeded()。然后在Swift 3中就可以正常工作了。 - Adam Studenic
@Dan，使用Swift时，在switch语句中不需要使用break（除非你想要一个nop）。 - gangelo
1
在设置UIBezierPath的半径时，如果要正确工作，需要将厚度减半，以适用于厚度>=1。 - Martin_G
显示剩余5条评论
86

对我来说最好的方法是创建一个UIView类别，在其中添加视图而不是CALayer，这样我们可以利用AutoresizingMask确保边框随着父视图一起调整大小。

Objective C

- (void)addTopBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth {
    UIView *border = [UIView new];
    border.backgroundColor = color;
    [border setAutoresizingMask:UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleBottomMargin];
    border.frame = CGRectMake(0, 0, self.frame.size.width, borderWidth);
    [self addSubview:border];
}

- (void)addBottomBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth {
    UIView *border = [UIView new];
    border.backgroundColor = color;
    [border setAutoresizingMask:UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleTopMargin];
    border.frame = CGRectMake(0, self.frame.size.height - borderWidth, self.frame.size.width, borderWidth);
    [self addSubview:border];
}

- (void)addLeftBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth {
    UIView *border = [UIView new];
    border.backgroundColor = color;
    border.frame = CGRectMake(0, 0, borderWidth, self.frame.size.height);
    [border setAutoresizingMask:UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleRightMargin];
    [self addSubview:border];
}

- (void)addRightBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth {
    UIView *border = [UIView new];
    border.backgroundColor = color;
    [border setAutoresizingMask:UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleLeftMargin];
    border.frame = CGRectMake(self.frame.size.width - borderWidth, 0, borderWidth, self.frame.size.height);
    [self addSubview:border];
}

Swift 5

func addTopBorder(with color: UIColor?, andWidth borderWidth: CGFloat) {
    let border = UIView()
    border.backgroundColor = color
    border.autoresizingMask = [.flexibleWidth, .flexibleBottomMargin]
    border.frame = CGRect(x: 0, y: 0, width: frame.size.width, height: borderWidth)
    addSubview(border)
}

func addBottomBorder(with color: UIColor?, andWidth borderWidth: CGFloat) {
    let border = UIView()
    border.backgroundColor = color
    border.autoresizingMask = [.flexibleWidth, .flexibleTopMargin]
    border.frame = CGRect(x: 0, y: frame.size.height - borderWidth, width: frame.size.width, height: borderWidth)
    addSubview(border)
}

func addLeftBorder(with color: UIColor?, andWidth borderWidth: CGFloat) {
    let border = UIView()
    border.backgroundColor = color
    border.frame = CGRect(x: 0, y: 0, width: borderWidth, height: frame.size.height)
    border.autoresizingMask = [.flexibleHeight, .flexibleRightMargin]
    addSubview(border)
}

func addRightBorder(with color: UIColor?, andWidth borderWidth: CGFloat) {
    let border = UIView()
    border.backgroundColor = color
    border.autoresizingMask = [.flexibleHeight, .flexibleLeftMargin]
    border.frame = CGRect(x: frame.size.width - borderWidth, y: 0, width: borderWidth, height: frame.size.height)
    addSubview(border)
}
9
这绝对是解决这个问题最好的方案之一。其他大多数解决方案都不能支持视图更改（因此无法旋转设备或使用分屏视图）。而这个方案可以。 - Womble
3
如何适应支持圆角？ - ntaj
该死！尽管在自定义视图的init中打印(self.frame.width)时得到0，但它像魔术一样运行良好。但顶部边框是正确的！ - Parth
38

Swift 3.0

Swift 4.1

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: frame.width, height: thickness)

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

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

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

    default: do {}
    }

    border.backgroundColor = color.cgColor

    addSublayer(border)
 }
}
2
当视图大小调整，例如方向改变时，这个功能将无法正常工作。 - Nestor
如果您正在使用基于框架的布局，则必须实现layoutSubviews并在其中重新计算所有子视图（或子层）框架。 - trapper
同样也不能作为一个视图的边框，如果该视图本身具有圆角半径。 - bubbaspike
24
< p > 子类化 < code > UIView 并在您的子类中实现 < code > drawRect: ，例如：< /p> < p > < strong > Objective-c < /p>
- (void)drawRect:(CGRect)rect {
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextMoveToPoint(context, CGRectGetMinX(rect), CGRectGetMinY(rect));
    CGContextAddLineToPoint(context, CGRectGetMaxX(rect), CGRectGetMinY(rect));
    CGContextSetStrokeColorWithColor(context, [[UIColor redColor] CGColor] );
    CGContextSetLineWidth(context, 2.0);
    CGContextStrokePath(context);
}

Swift 4

override func draw(_ rect: CGRect) {

    let cgContext = UIGraphicsGetCurrentContext()
    cgContext?.move(to: CGPoint(x: rect.minX, y: rect.minY))
    cgContext?.addLine(to: CGPoint(x: rect.maxX, y: rect.minY))
    cgContext?.setStrokeColor(UIColor.red.cgColor)
    cgContext?.setLineWidth(2.0)
    cgContext?.strokePath()
}

这会在顶部绘制一条2像素的红色线框。其他您提到的变化留给读者自己完成。

推荐使用Quartz 2D编程指南。

这是唯一的方法吗？如果我需要创建一个带有顶部边框的视图，另一个带有底部边框的视图，以及其他视图...我的意思是始终使用特定视图来添加一个或两个边框，那么我每次都需要为每种情况创建一个子类吗？我不知道仅仅为了添加边框而创建类是否真的很好。 - manonthemoon
1
不。想想看。你的UIView子类可以有一个属性，用来决定drawRect:方法绘制哪些边框。这个属性可以使用NS_OPTIONS定义，以便像UIViewAutoresizing中的位掩码那样进行定义。如果出于任何原因，你非常反对继承UIView，那么只需添加一个高度为1-2像素（或宽度）的小子视图，并给它任意尺寸来模拟一个边框即可。 - FluffulousChimp
大家好，我创建了一个受这段代码启发的Swift子类，希望你们喜欢它：https://gist.github.com/asiviero/4f52ab7dea7d9252a64c - asiviero
19

如果有人需要，这是选定答案的代码。

注意：此方法不适用于自动布局（例如旋转设备横屏等）。

首先定义一个厚度：

NSInteger borderThickness = 1;

然后只需复制使用这些中的任何一个或全部来设置您想要设置的边框。

顶部边框

UIView *topBorder = [UIView new];
topBorder.backgroundColor = [UIColor lightGrayColor];
topBorder.frame = CGRectMake(0, 0, myView.frame.size.width, borderThickness);
[myView addSubview:topBorder];

底部边框

UIView *bottomBorder = [UIView new];
bottomBorder.backgroundColor = [UIColor lightGrayColor];
bottomBorder.frame = CGRectMake(0, myView.frame.size.height - borderThickness, myView.frame.size.width, borderThickness);
[myView addSubview:bottomBorder];

左边框

UIView *leftBorder = [UIView new];
leftBorder.backgroundColor = [UIColor lightGrayColor];
leftBorder.frame = CGRectMake(0, 0, borderThickness, myView.frame.size.height);
[myView addSubview:leftBorder];

右边框

UIView *rightBorder = [UIView new];
rightBorder.backgroundColor = [UIColor lightGrayColor];
rightBorder.frame = CGRectMake(myView.frame.size.width - borderThickness, 0, borderThickness, myView.frame.size.height);
[myView addSubview:rightBorder];
相比于裸的CALayer，使用UIView会增加一些开销，但是这是一种更为直接简单的解决方案。 - Soberman
在阅读了所有其他解决方案之后，我想我也会添加一个小视图。为了一个边框而做那么多工作！这个解决方案只需要几个引脚就可以在自动布局中工作。更容易理解。 - noobsmcgoobs
谢谢，我已经添加了一个注释，这样程序员就只会在他们的应用程序不旋转时使用。 - Travis M.
17

虽然这是一个老问题，但运行时自动布局解决方案仍然缺少对边框的调整。

borders(for: [.left, .bottom], width: 2, color: .red)
下面的UIView扩展将仅在给定的边缘添加边框。如果您在运行时更改边缘，则边框将相应调整。
extension UIView {
    func borders(for edges:[UIRectEdge], width:CGFloat = 1, color: UIColor = .black) {

        if edges.contains(.all) {
            layer.borderWidth = width
            layer.borderColor = color.cgColor
        } else {
            let allSpecificBorders:[UIRectEdge] = [.top, .bottom, .left, .right]

            for edge in allSpecificBorders {
                if let v = viewWithTag(Int(edge.rawValue)) {
                    v.removeFromSuperview()
                }

                if edges.contains(edge) {
                    let v = UIView()
                    v.tag = Int(edge.rawValue)
                    v.backgroundColor = color
                    v.translatesAutoresizingMaskIntoConstraints = false
                    addSubview(v)

                    var horizontalVisualFormat = "H:"
                    var verticalVisualFormat = "V:"

                    switch edge {
                    case UIRectEdge.bottom:
                        horizontalVisualFormat += "|-(0)-[v]-(0)-|"
                        verticalVisualFormat += "[v(\(width))]-(0)-|"
                    case UIRectEdge.top:
                        horizontalVisualFormat += "|-(0)-[v]-(0)-|"
                        verticalVisualFormat += "|-(0)-[v(\(width))]"
                    case UIRectEdge.left:
                        horizontalVisualFormat += "|-(0)-[v(\(width))]"
                        verticalVisualFormat += "|-(0)-[v]-(0)-|"
                    case UIRectEdge.right:
                        horizontalVisualFormat += "[v(\(width))]-(0)-|"
                        verticalVisualFormat += "|-(0)-[v]-(0)-|"
                    default:
                        break
                    }

                    self.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: horizontalVisualFormat, options: .directionLeadingToTrailing, metrics: nil, views: ["v": v]))
                    self.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: verticalVisualFormat, options: .directionLeadingToTrailing, metrics: nil, views: ["v": v]))
                }
            }
        }
    }
}
14

Swift版本：

var myView = UIView(frame: CGRect(x: 100, y: 100, width: 100, height: 100))
myView.backgroundColor = UIColor.yellowColor() 

var border = CALayer()
border.backgroundColor = UIColor.lightGrayColor()
border.frame = CGRect(x: 0, y: 0, width: myView.frame.width, height: 0.5)

myView.layer.addSublayer(border)

编辑：查看更新版本请在此处检查我的存储库： https://github.com/goktugyil/EZSwiftExtensions/blob/master/Sources/UIViewExtensions.swift

看看addBorder部分。

10

Swift 4.2和AutoLayout

我查阅了提供的解决方案。许多都基于框架。这是一个简单的扩展，可以与AutoLayout一起使用。 - 使用View而不是Layer以确保我们可以使用AutoLayout - 只有一个子视图且有4个约束条件

使用方法如下：

self.addBorder(.bottom, color: .lightGray, thickness: 0.5)


extension UIView {
    func addBorder(_ edge: UIRectEdge, color: UIColor, thickness: CGFloat) {
        let subview = UIView()
        subview.translatesAutoresizingMaskIntoConstraints = false
        subview.backgroundColor = color
        self.addSubview(subview)
        switch edge {
        case .top, .bottom:
            subview.leftAnchor.constraint(equalTo: self.leftAnchor, constant: 0).isActive = true
            subview.rightAnchor.constraint(equalTo: self.rightAnchor, constant: 0).isActive = true
            subview.heightAnchor.constraint(equalToConstant: thickness).isActive = true
            if edge == .top {
                subview.topAnchor.constraint(equalTo: self.topAnchor, constant: 0).isActive = true
            } else {
                subview.bottomAnchor.constraint(equalTo: self.bottomAnchor, constant: 0).isActive = true
            }
        case .left, .right:
            subview.topAnchor.constraint(equalTo: self.topAnchor, constant: 0).isActive = true
            subview.bottomAnchor.constraint(equalTo: self.bottomAnchor, constant: 0).isActive = true
            subview.widthAnchor.constraint(equalToConstant: thickness).isActive = true
            if edge == .left {
                subview.leftAnchor.constraint(equalTo: self.leftAnchor, constant: 0).isActive = true
            } else {
                subview.rightAnchor.constraint(equalTo: self.rightAnchor, constant: 0).isActive = true
            }
        default:
            break
        }
    }
}
5

Swift 5

编译之前回答的一些问题并添加额外的便捷方法

import UIKit

extension UIView {
    enum ViewSide {
        case top
        case left
        case bottom
        case right
    }

    func addBorders(to sides: [ViewSide], in color: UIColor, width: CGFloat) {
        sides.forEach { addBorder(to: $0, in: color, width: width) }
    }

    func addBorder(to side: ViewSide, in color: UIColor, width: CGFloat) {
        switch side {
        case .top:
            addTopBorder(in: color, width: width)
        case .left:
            addLeftBorder(in: color, width: width)
        case .bottom:
            addBottomBorder(in: color, width: width)
        case .right:
            addRightBorder(in: color, width: width)
        }
    }

    func addTopBorder(in color: UIColor?, width borderWidth: CGFloat) {
        let border = UIView()
        border.backgroundColor = color
        border.frame = CGRect(x: 0, y: 0, width: frame.size.width, height: borderWidth)
        border.autoresizingMask = [.flexibleWidth, .flexibleBottomMargin]
        addSubview(border)
    }

    func addBottomBorder(in color: UIColor?, width borderWidth: CGFloat) {
        let border = UIView()
        border.backgroundColor = color
        border.frame = CGRect(x: 0, y: frame.size.height - borderWidth, width: frame.size.width, height: borderWidth)
        border.autoresizingMask = [.flexibleWidth, .flexibleTopMargin]
        addSubview(border)
    }

    func addLeftBorder(in color: UIColor?, width borderWidth: CGFloat) {
        let border = UIView()
        border.backgroundColor = color
        border.frame = CGRect(x: 0, y: 0, width: borderWidth, height: frame.size.height)
        border.autoresizingMask = [.flexibleHeight, .flexibleRightMargin]
        addSubview(border)
    }

    func addRightBorder(in color: UIColor?, width borderWidth: CGFloat) {
        let border = UIView()
        border.backgroundColor = color
        border.frame = CGRect(x: frame.size.width - borderWidth, y: 0, width: borderWidth, height: frame.size.height)
        border.autoresizingMask = [.flexibleHeight, .flexibleLeftMargin]
        addSubview(border)
    }
}

您可以选择以下方式之一：
  1. 通过特定方法或通用方法分别设置每个边框，根据您的情况进行选择
  2. 设置一个边框数组

使用示例：

// Adding top border with 2 px in red
let myView = UIView()
myView.addBorder(to: .top, in: .red, width: 2)

也许您可以消除来自两个可能可用接口的歧义，只需将辅助方法设为私有... 我不会将它们从那里删除并将每个情况移动到主方法中，因为在我看来，这样可能会使其代码混乱。

@Vivek修正了参数标签，谢谢 - Lucas Werner Kuipers
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