小开

您可以添加一个单独的 UIView与1点高度和灰色背景颜色的 self.view和位置正好低于 toScrollView。

编辑: 除非你有一个很好的理由(想使用 UIView 的一些服务，而不是由 CALayer 提供) ，你应该使用 CALayer 作为 @ MattDiPasquale 建议。UIView 有更大的开销，这在大多数情况下可能不是问题，但是另一个解决方案更加优雅。

小开

最佳答案

与@ImreKel ényi 建议的使用 UIView不同，你可以使用 CALayer:

// Add a bottomBorder.
CALayer *bottomBorder = [CALayer layer];


bottomBorder.frame = CGRectMake(0.0f, 43.0f, toScrollView.frame.size.width, 1.0f);


bottomBorder.backgroundColor = [UIColor colorWithWhite:0.8f
alpha:1.0f].CGColor;


[toScrollView.layer addSublayer:bottomBorder];

小开

我写了一个通用的方法，将添加一个边界的任何一方你希望在任何 UIView。您可以为每一边定义厚度、颜色、边距和 zOrder。

/*
view: the view to draw border around
thickness: thickness of the border on the given side
color: color of the border on the given side
margin: space between the border's outer edge and the view's frame edge on the given side.
zOrder: defines the order to add the borders to the view.  The borders will be added by zOrder from lowest to highest, thus making the highest priority border visible when two borders overlap at the corners.
*/


+(void) drawBorderAroundUIView:(UIView *) view thicknessLeft:(CGFloat) thicknessLeft colorLeft:(UIColor *)colorLeft marginLeft:(CGFloat) marginLeft zOrderLeft:(int) zOrderLeft thicknessRight:(CGFloat) thicknessRight colorRight:(UIColor *)colorRight marginRight:(CGFloat) marginRight zOrderRight:(int) zOrderRight thicknessTop:(CGFloat) thicknessTop colorTop:(UIColor *)colorTop marginTop:(CGFloat) marginTop zOrderTop:(int) zOrderTop thicknessBottom:(CGFloat) thicknessBottom colorBottom:(UIColor *)colorBottom marginBottom:(CGFloat) marginBottom zOrderBottom:(int) zOrderBottom{
//make margins be the outside edge and make positive margin represent a smaller rectangle
marginBottom = -1 * marginBottom - thicknessBottom;
marginTop = -1 * marginTop - thicknessTop;
marginLeft = -1 * marginLeft - thicknessLeft;
marginRight = -1 * marginRight - thicknessRight;


//get reference points for corners
CGPoint upperLeftCorner = CGPointZero;
CGPoint lowerLeftCorner = CGPointMake(upperLeftCorner.x, upperLeftCorner.y + view.frame.size.height);
CGPoint upperRightCorner = CGPointMake(upperLeftCorner.x + view.frame.size.width, upperLeftCorner.y);


//left
CALayer *leftBorder = [CALayer layer];
leftBorder.frame = CGRectMake(upperLeftCorner.x - thicknessLeft - marginLeft, upperLeftCorner.y - thicknessTop - marginTop, thicknessLeft, view.frame.size.height + marginTop + marginBottom + thicknessBottom + thicknessTop);
leftBorder.backgroundColor = colorLeft.CGColor;


//right
CALayer *rightBorder = [CALayer layer];
rightBorder.frame = CGRectMake(upperRightCorner.x + marginRight, upperRightCorner.y - thicknessTop - marginTop, thicknessRight, view.frame.size.height + marginTop + marginBottom + thicknessBottom + thicknessTop);
rightBorder.backgroundColor = colorRight.CGColor;


//top
CALayer *topBorder = [CALayer layer];
topBorder.frame = CGRectMake(upperLeftCorner.x - thicknessLeft - marginLeft, upperLeftCorner.y - thicknessTop - marginTop, view.frame.size.width + marginLeft + marginRight + thicknessLeft + thicknessRight, thicknessTop);
topBorder.backgroundColor = colorTop.CGColor;


//bottom
CALayer *bottomBorder = [CALayer layer];
bottomBorder.frame = CGRectMake(upperLeftCorner.x - thicknessLeft - marginLeft, lowerLeftCorner.y + marginBottom, view.frame.size.width + marginLeft + marginRight + thicknessLeft + thicknessRight, thicknessBottom);
bottomBorder.backgroundColor = colorBottom.CGColor;


//define dictionary keys to be used for adding borders in order of zOrder
NSString *borderDK = @"border";
NSString *zOrderDK = @"zOrder";


//storing borders in dictionaries in preparation to add them in order of zOrder
NSDictionary *leftBorderDictionary = [NSDictionary dictionaryWithObjectsAndKeys:leftBorder, borderDK, [NSNumber numberWithInt:zOrderLeft], zOrderDK, nil];
NSDictionary *rightBorderDictionary = [NSDictionary dictionaryWithObjectsAndKeys:rightBorder, borderDK, [NSNumber numberWithInt:zOrderRight], zOrderDK, nil];
NSDictionary *topBorderDictionary = [NSDictionary dictionaryWithObjectsAndKeys:topBorder, borderDK, [NSNumber numberWithInt:zOrderTop], zOrderDK, nil];
NSDictionary *bottomBorderDictionary = [NSDictionary dictionaryWithObjectsAndKeys:bottomBorder, borderDK, [NSNumber numberWithInt:zOrderBottom], zOrderDK, nil];


NSMutableArray *borders = [NSMutableArray arrayWithObjects:leftBorderDictionary, rightBorderDictionary, topBorderDictionary, bottomBorderDictionary, nil];


//add borders in order of zOrder (lowest -> highest).  Thus the highest zOrder will be added last so it will be on top.
while (borders.count)
{
//look for the next lowest zOrder border to add
NSDictionary *nextBorderToLayDown = [borders objectAtIndex:0];
for (int indexOfBorder = 0; indexOfBorder < borders.count; indexOfBorder++)
{
NSDictionary *borderAtIndex = [borders objectAtIndex:indexOfBorder];
if ([[borderAtIndex objectForKey:zOrderDK] intValue] < [[nextBorderToLayDown objectForKey:zOrderDK] intValue])
{
nextBorderToLayDown = borderAtIndex;
}
}
//add the border to the view
[view.layer addSublayer:[nextBorderToLayDown objectForKey:borderDK]];
[borders removeObject:nextBorderToLayDown];
}
}

小开

按下列类别执行:

UIButton + Border.h:

@interface UIButton (Border)


- (void)addBottomBorderWithColor: (UIColor *) color andWidth:(CGFloat) borderWidth;


- (void)addLeftBorderWithColor: (UIColor *) color andWidth:(CGFloat) borderWidth;


- (void)addRightBorderWithColor: (UIColor *) color andWidth:(CGFloat) borderWidth;


- (void)addTopBorderWithColor: (UIColor *) color andWidth:(CGFloat) borderWidth;


@end

UIButton + Border.m:

@implementation UIButton (Border)


- (void)addTopBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth {
CALayer *border = [CALayer layer];
border.backgroundColor = color.CGColor;


border.frame = CGRectMake(0, 0, self.frame.size.width, borderWidth);
[self.layer addSublayer:border];
}


- (void)addBottomBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth {
CALayer *border = [CALayer layer];
border.backgroundColor = color.CGColor;


border.frame = CGRectMake(0, self.frame.size.height - borderWidth, self.frame.size.width, borderWidth);
[self.layer addSublayer:border];
}


- (void)addLeftBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth {
CALayer *border = [CALayer layer];
border.backgroundColor = color.CGColor;


border.frame = CGRectMake(0, 0, borderWidth, self.frame.size.height);
[self.layer addSublayer:border];
}


- (void)addRightBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth {
CALayer *border = [CALayer layer];
border.backgroundColor = color.CGColor;


border.frame = CGRectMake(self.frame.size.width - borderWidth, 0, borderWidth, self.frame.size.height);
[self.layer addSublayer:border];
}


@end

小开

或者，最有利于性能的方法是过载 draRect，就像这样:

@interface TPActionSheetButton : UIButton


@property (assign) BOOL drawsTopLine;
@property (assign) BOOL drawsBottomLine;
@property (assign) BOOL drawsRightLine;
@property (assign) BOOL drawsLeftLine;
@property (strong, nonatomic) UIColor * lineColor;


@end


@implementation TPActionSheetButton


- (void) drawRect:(CGRect)rect
{
CGContextRef ctx = UIGraphicsGetCurrentContext();


CGContextSetLineWidth(ctx, 0.5f * [[UIScreen mainScreen] scale]);
CGFloat red, green, blue, alpha;
[self.lineColor getRed:&red green:&green blue:&blue alpha:&alpha];
CGContextSetRGBStrokeColor(ctx, red, green, blue, alpha);


if(self.drawsTopLine) {
CGContextBeginPath(ctx);
CGContextMoveToPoint(ctx, CGRectGetMinX(rect), CGRectGetMinY(rect));
CGContextAddLineToPoint(ctx, CGRectGetMaxX(rect), CGRectGetMinY(rect));
CGContextStrokePath(ctx);
}
if(self.drawsBottomLine) {
CGContextBeginPath(ctx);
CGContextMoveToPoint(ctx, CGRectGetMinX(rect), CGRectGetMaxY(rect));
CGContextAddLineToPoint(ctx, CGRectGetMaxX(rect), CGRectGetMaxY(rect));
CGContextStrokePath(ctx);
}
if(self.drawsLeftLine) {
CGContextBeginPath(ctx);
CGContextMoveToPoint(ctx, CGRectGetMinX(rect), CGRectGetMinY(rect));
CGContextAddLineToPoint(ctx, CGRectGetMinX(rect), CGRectGetMaxY(rect));
CGContextStrokePath(ctx);
}
if(self.drawsRightLine) {
CGContextBeginPath(ctx);
CGContextMoveToPoint(ctx, CGRectGetMaxX(rect), CGRectGetMinY(rect));
CGContextAddLineToPoint(ctx, CGRectGetMaxX(rect), CGRectGetMaxY(rect));
CGContextStrokePath(ctx);
}


[super drawRect:rect];
}


@end

小开

下面是一个更通用的 Swift 扩展，它可以为任何 UIView子类创建边界:

import UIKit


extension UIView {
func addTopBorderWithColor(color: UIColor, width: CGFloat) {
let border = CALayer()
border.backgroundColor = color.CGColor
border.frame = CGRectMake(0, 0, self.frame.size.width, width)
self.layer.addSublayer(border)
}


func addRightBorderWithColor(color: UIColor, width: CGFloat) {
let border = CALayer()
border.backgroundColor = color.CGColor
border.frame = CGRectMake(self.frame.size.width - width, 0, width, self.frame.size.height)
self.layer.addSublayer(border)
}


func addBottomBorderWithColor(color: UIColor, width: CGFloat) {
let border = CALayer()
border.backgroundColor = color.CGColor
border.frame = CGRectMake(0, self.frame.size.height - width, self.frame.size.width, width)
self.layer.addSublayer(border)
}


func addLeftBorderWithColor(color: UIColor, width: CGFloat) {
let border = CALayer()
border.backgroundColor = color.CGColor
border.frame = CGRectMake(0, 0, width, self.frame.size.height)
self.layer.addSublayer(border)
}
}

Swift 3

extension UIView {
func addTopBorderWithColor(color: UIColor, width: CGFloat) {
let border = CALayer()
border.backgroundColor = color.cgColor
border.frame = CGRect(x: 0, y: 0, width: self.frame.size.width, height: width)
self.layer.addSublayer(border)
}


func addRightBorderWithColor(color: UIColor, width: CGFloat) {
let border = CALayer()
border.backgroundColor = color.cgColor
border.frame = CGRect(x: self.frame.size.width - width, y: 0, width: width, height: self.frame.size.height)
self.layer.addSublayer(border)
}


func addBottomBorderWithColor(color: UIColor, width: CGFloat) {
let border = CALayer()
border.backgroundColor = color.cgColor
border.frame = CGRect(x: 0, y: self.frame.size.height - width, width: self.frame.size.width, height: width)
self.layer.addSublayer(border)
}


func addLeftBorderWithColor(color: UIColor, width: CGFloat) {
let border = CALayer()
border.backgroundColor = color.cgColor
border.frame = CGRect(x: 0, y: 0, width: width, height: self.frame.size.height)
self.layer.addSublayer(border)
}
}

小开

您不必为每个边框添加一个图层，只需使用贝塞尔路径绘制一次。

CGRect rect = self.bounds;


CGPoint destPoint[4] = {CGPointZero,
(CGPoint){0, rect.size.height},
(CGPoint){rect.size.width, rect.size.height},
(CGPoint){rect.size.width, 0}};


BOOL position[4] = {_top, _left, _bottom, _right};


UIBezierPath *path = [UIBezierPath new];
[path moveToPoint:destPoint[3]];


for (int i = 0; i < 4; ++i) {
if (position[i]) {
[path addLineToPoint:destPoint[i]];
} else {
[path moveToPoint:destPoint[i]];
}
}


CAShapeLayer *borderLayer = [CAShapeLayer new];
borderLayer.frame = self.bounds;
borderLayer.path  = path.CGPath;
borderLayer.lineWidth   = _borderWidth ?: 1 / [UIScreen mainScreen].scale;
borderLayer.strokeColor = _borderColor.CGColor;
borderLayer.fillColor   = [UIColor clearColor].CGColor;


[self.layer addSublayer:borderLayer];

小开

也有改进的代码与移除边界功能。

import UIKit


enum viewBorder: String {
case Left = "borderLeft"
case Right = "borderRight"
case Top = "borderTop"
case Bottom = "borderBottom"
}


extension UIView {


func addBorder(vBorder: viewBorder, color: UIColor, width: CGFloat) {
let border = CALayer()
border.backgroundColor = color.CGColor
border.name = vBorder.rawValue
switch vBorder {
case .Left:
border.frame = CGRectMake(0, 0, width, self.frame.size.height)
case .Right:
border.frame = CGRectMake(self.frame.size.width - width, 0, width, self.frame.size.height)
case .Top:
border.frame = CGRectMake(0, 0, self.frame.size.width, width)
case .Bottom:
border.frame = CGRectMake(0, self.frame.size.height - width, self.frame.size.width, width)
}
self.layer.addSublayer(border)
}


func removeBorder(border: viewBorder) {
var layerForRemove: CALayer?
for layer in self.layer.sublayers! {
if layer.name == border.rawValue {
layerForRemove = layer
}
}
if let layer = layerForRemove {
layer.removeFromSuperlayer()
}
}


}

更新: Swift 3

import UIKit


enum ViewBorder: String {
case left, right, top, bottom
}


extension UIView {


func add(border: ViewBorder, color: UIColor, width: CGFloat) {
let borderLayer = CALayer()
borderLayer.backgroundColor = color.cgColor
borderLayer.name = border.rawValue
switch border {
case .left:
borderLayer.frame = CGRect(x: 0, y: 0, width: width, height: self.frame.size.height)
case .right:
borderLayer.frame = CGRect(x: self.frame.size.width - width, y: 0, width: width, height: self.frame.size.height)
case .top:
borderLayer.frame = CGRect(x: 0, y: 0, width: self.frame.size.width, height: width)
case .bottom:
borderLayer.frame = CGRect(x: 0, y: self.frame.size.height - width, width: self.frame.size.width, height: width)
}
self.layer.addSublayer(borderLayer)
}


func remove(border: ViewBorder) {
guard let sublayers = self.layer.sublayers else { return }
var layerForRemove: CALayer?
for layer in sublayers {
if layer.name == border.rawValue {
layerForRemove = layer
}
}
if let layer = layerForRemove {
layer.removeFromSuperlayer()
}
}


}

小开

Swift 4

如果你需要一个真正的 适应性强解决方案(对于所有屏幕尺寸) ，那么这就是它:

/**
* Extends UIView with shortcut methods
*
* @author Alexander Volkov
* @version 1.0
*/
extension UIView {


/// Adds bottom border to the view with given side margins
///
/// - Parameters:
///   - color: the border color
///   - margins: the left and right margin
///   - borderLineSize: the size of the border
func addBottomBorder(color: UIColor = UIColor.red, margins: CGFloat = 0, borderLineSize: CGFloat = 1) {
let border = UIView()
border.backgroundColor = color
border.translatesAutoresizingMaskIntoConstraints = false
self.addSubview(border)
border.addConstraint(NSLayoutConstraint(item: border,
attribute: .height,
relatedBy: .equal,
toItem: nil,
attribute: .height,
multiplier: 1, constant: borderLineSize))
self.addConstraint(NSLayoutConstraint(item: border,
attribute: .bottom,
relatedBy: .equal,
toItem: self,
attribute: .bottom,
multiplier: 1, constant: 0))
self.addConstraint(NSLayoutConstraint(item: border,
attribute: .leading,
relatedBy: .equal,
toItem: self,
attribute: .leading,
multiplier: 1, constant: margins))
self.addConstraint(NSLayoutConstraint(item: border,
attribute: .trailing,
relatedBy: .equal,
toItem: self,
attribute: .trailing,
multiplier: 1, constant: margins))
}
}

小开

这些扩展方法的问题在于，当 UIView/UIButton 稍后调整它的大小时，您没有机会更改 CALayer 的大小以匹配新的大小。这样就会留下一个错误的边界。我发现最好子类化我的 UIButton，当然你也可以子类化其他的 UIView。下面是一些代码:

enum BorderedButtonSide {
case Top, Right, Bottom, Left
}




class BorderedButton : UIButton {


private var borderTop: CALayer?
private var borderTopWidth: CGFloat?
private var borderRight: CALayer?
private var borderRightWidth: CGFloat?
private var borderBottom: CALayer?
private var borderBottomWidth: CGFloat?
private var borderLeft: CALayer?
private var borderLeftWidth: CGFloat?




func setBorder(side: BorderedButtonSide, _ color: UIColor, _ width: CGFloat) {


let border = CALayer()
border.backgroundColor = color.CGColor


switch side {
case .Top:
border.frame = CGRect(x: 0, y: 0, width: frame.size.width, height: width)
borderTop?.removeFromSuperlayer()
borderTop = border
borderTopWidth = width
case .Right:
border.frame = CGRect(x: frame.size.width - width, y: 0, width: width, height: frame.size.height)
borderRight?.removeFromSuperlayer()
borderRight = border
borderRightWidth = width
case .Bottom:
border.frame = CGRect(x: 0, y: frame.size.height - width, width: frame.size.width, height: width)
borderBottom?.removeFromSuperlayer()
borderBottom = border
borderBottomWidth = width
case .Left:
border.frame = CGRect(x: 0, y: 0, width: width, height: frame.size.height)
borderLeft?.removeFromSuperlayer()
borderLeft = border
borderLeftWidth = width
}


layer.addSublayer(border)
}


override func layoutSubviews() {
super.layoutSubviews()
borderTop?.frame = CGRect(x: 0, y: 0, width: frame.size.width, height: borderTopWidth!)
borderRight?.frame = CGRect(x: frame.size.width - borderRightWidth!, y: 0, width: borderRightWidth!, height: frame.size.height)
borderBottom?.frame = CGRect(x: 0, y: frame.size.height - borderBottomWidth!, width: frame.size.width, height: borderBottomWidth!)
borderLeft?.frame = CGRect(x: 0, y: 0, width: borderLeftWidth!, height: frame.size.height)
}


}

小开

最完整的答案

let rectangle = UIView(frame: CGRect(x: 100, y: 100, width: 100, height: 60))
rectangle.backgroundColor = UIColor.grayColor()
view.addSubview(rectangle)
rectangle.borderTop = Border(size: 3, color: UIColor.orangeColor(), offset: UIEdgeInsets(top: 0, left: -10, bottom: 0, right: -5))
rectangle.borderBottom = Border(size: 6, color: UIColor.redColor(), offset: UIEdgeInsets(top: 0, left: 10, bottom: 10, right: 0))
rectangle.borderLeft = Border(size: 2, color: UIColor.blueColor(), offset: UIEdgeInsets(top: 10, left: -10, bottom: 0, right: 0))
rectangle.borderRight = Border(size: 2, color: UIColor.greenColor(), offset: UIEdgeInsets(top: 10, left: 10, bottom: 0, right: 0))

小开

Swift 3版本的 Confile 回答:

import UIKit


extension UIView {
func addTopBorderWithColor(color: UIColor, width: CGFloat) {
let border = CALayer()
border.backgroundColor = color.cgColor
border.frame = CGRect(x: 0, y: 0, width: self.frame.size.width, height: width)
self.layer.addSublayer(border)
}


func addRightBorderWithColor(color: UIColor, width: CGFloat) {
let border = CALayer()
border.backgroundColor = color.cgColor
border.frame = CGRect(x: self.frame.size.width - width, y: 0, width: width, height: self.frame.size.height)
self.layer.addSublayer(border)
}


func addBottomBorderWithColor(color: UIColor, width: CGFloat) {
let border = CALayer()
border.backgroundColor = color.cgColor
border.frame = CGRect(x: 0, y: self.frame.size.height - width, width: self.frame.size.width, height: width)
self.layer.addSublayer(border)
}


func addLeftBorderWithColor(color: UIColor, width: CGFloat) {
let border = CALayer()
border.backgroundColor = color.cgColor
border.frame = CGRect(x: 0, y: 0, width: width, height: self.frame.size.height)
self.layer.addSublayer(border)
}
}

使用自动布局的用法:

class CustomView: UIView {


override func awakeFromNib() {
super.awakeFromNib()
}


override func layoutSubviews() {
addBottomBorderWithColor(color: UIColor.white, width: 1)
}
}

小开

斯威夫特4/3

您可以在下面使用此解决方案。它工作在比层更轻的 UIBezierPath 上，导致快速启动时间。它很容易使用，请看下面的说明。

class ResizeBorderView: UIView {
var color = UIColor.white
var lineWidth: CGFloat = 1
var edges = [UIRectEdge](){
didSet {
setNeedsDisplay()
}
}
override func draw(_ rect: CGRect) {
if edges.contains(.top) || edges.contains(.all){
let path = UIBezierPath()
path.lineWidth = lineWidth
color.setStroke()
UIColor.blue.setFill()
path.move(to: CGPoint(x: 0, y: 0 + lineWidth / 2))
path.addLine(to: CGPoint(x: self.bounds.width, y: 0 + lineWidth / 2))
path.stroke()
}
if edges.contains(.bottom) || edges.contains(.all){
let path = UIBezierPath()
path.lineWidth = lineWidth
color.setStroke()
UIColor.blue.setFill()
path.move(to: CGPoint(x: 0, y: self.bounds.height - lineWidth / 2))
path.addLine(to: CGPoint(x: self.bounds.width, y: self.bounds.height - lineWidth / 2))
path.stroke()
}
if edges.contains(.left) || edges.contains(.all){
let path = UIBezierPath()
path.lineWidth = lineWidth
color.setStroke()
UIColor.blue.setFill()
path.move(to: CGPoint(x: 0 + lineWidth / 2, y: 0))
path.addLine(to: CGPoint(x: 0 + lineWidth / 2, y: self.bounds.height))
path.stroke()
}
if edges.contains(.right) || edges.contains(.all){
let path = UIBezierPath()
path.lineWidth = lineWidth
color.setStroke()
UIColor.blue.setFill()
path.move(to: CGPoint(x: self.bounds.width - lineWidth / 2, y: 0))
path.addLine(to: CGPoint(x: self.bounds.width - lineWidth / 2, y: self.bounds.height))
path.stroke()
}
}
}

将 UIView 的类设置为 ResizeBorderView
在 viewDidAppear 方法中使用 yourview.color 和 yourview.lineWidth 设置颜色和行宽
为 all 设置边缘，例如: yourview.edge = [ . right，. left ]([ . all ])
享受快速启动和调整边框大小

小开

斯威夫特

创建 UIView 扩展

private var bottomLineColorAssociatedKey : UIColor = .black private var topLineColorAssociatedKey : UIColor = .black private var rightLineColorAssociatedKey : UIColor = .black private var leftLineColorAssociatedKey : UIColor = .black extension UIView { @IBInspectable var bottomLineColor: UIColor { get { if let color = objc_getAssociatedObject(self, &bottomLineColorAssociatedKey) as? UIColor { return color } else { return .black } } set { objc_setAssociatedObject(self, &bottomLineColorAssociatedKey, newValue, .OBJC_ASSOCIATION_RETAIN) } } @IBInspectable var bottomLineWidth: CGFloat { get { return self.bottomLineWidth } set { DispatchQueue.main.async { self.addBottomBorderWithColor(color: self.bottomLineColor, width: newValue) } } } @IBInspectable var topLineColor: UIColor { get { if let color = objc_getAssociatedObject(self, &topLineColorAssociatedKey) as? UIColor { return color } else { return .black } } set { objc_setAssociatedObject(self, &topLineColorAssociatedKey, newValue, .OBJC_ASSOCIATION_RETAIN) } } @IBInspectable var topLineWidth: CGFloat { get { return self.topLineWidth } set { DispatchQueue.main.async { self.addTopBorderWithColor(color: self.topLineColor, width: newValue) } } } @IBInspectable var rightLineColor: UIColor { get { if let color = objc_getAssociatedObject(self, &rightLineColorAssociatedKey) as? UIColor { return color } else { return .black } } set { objc_setAssociatedObject(self, &rightLineColorAssociatedKey, newValue, .OBJC_ASSOCIATION_RETAIN) } } @IBInspectable var rightLineWidth: CGFloat { get { return self.rightLineWidth } set { DispatchQueue.main.async { self.addRightBorderWithColor(color: self.rightLineColor, width: newValue) } } } @IBInspectable var leftLineColor: UIColor { get { if let color = objc_getAssociatedObject(self, &leftLineColorAssociatedKey) as? UIColor { return color } else { return .black } } set { objc_setAssociatedObject(self, &leftLineColorAssociatedKey, newValue, .OBJC_ASSOCIATION_RETAIN) } } @IBInspectable var leftLineWidth: CGFloat { get { return self.leftLineWidth } set { DispatchQueue.main.async { self.addLeftBorderWithColor(color: self.leftLineColor, width: newValue) } } } func addTopBorderWithColor(color: UIColor, width: CGFloat) { let border = CALayer() border.name = "topBorderLayer" removePreviouslyAddedLayer(name: border.name ?? "") border.backgroundColor = color.cgColor border.frame = CGRect(x: 0, y : 0,width: self.frame.size.width, height: width) self.layer.addSublayer(border) self.addObserver(self, forKeyPath: #keyPath(UIView.bounds), options: .new, context: UnsafeMutableRawPointer(bitPattern: 1111) ) } func addRightBorderWithColor(color: UIColor, width: CGFloat) { let border = CALayer() border.name = "rightBorderLayer" removePreviouslyAddedLayer(name: border.name ?? "") border.backgroundColor = color.cgColor border.frame = CGRect(x: self.frame.size.width - width, y: 0, width : width, height :self.frame.size.height) self.layer.addSublayer(border) self.addObserver(self, forKeyPath: #keyPath(UIView.bounds), options: .new, context: UnsafeMutableRawPointer(bitPattern: 2222) ) } func addBottomBorderWithColor(color: UIColor, width: CGFloat) { let border = CALayer() border.name = "bottomBorderLayer" removePreviouslyAddedLayer(name: border.name ?? "") border.backgroundColor = color.cgColor border.frame = CGRect(x: 0, y: self.frame.size.height - width,width : self.frame.size.width,height: width) self.layer.addSublayer(border) self.addObserver(self, forKeyPath: #keyPath(UIView.bounds), options: .new, context: UnsafeMutableRawPointer(bitPattern: 3333) ) } func addLeftBorderWithColor(color: UIColor, width: CGFloat) { let border = CALayer() border.name = "leftBorderLayer" removePreviouslyAddedLayer(name: border.name ?? "") border.backgroundColor = color.cgColor border.frame = CGRect(x:0, y:0,width : width, height : self.frame.size.height) self.layer.addSublayer(border) self.addObserver(self, forKeyPath: #keyPath(UIView.bounds), options: .new, context: UnsafeMutableRawPointer(bitPattern: 4444) ) } override open func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) { if let objectView = object as? UIView, objectView === self, keyPath == #keyPath(UIView.bounds) { switch context { case UnsafeMutableRawPointer(bitPattern: 1111): for border in self.layer.sublayers ?? [] { if border.name == "topBorderLayer" { border.frame = CGRect(x: 0, y : 0,width: self.frame.size.width, height: border.frame.height) } } case UnsafeMutableRawPointer(bitPattern: 2222): for border in self.layer.sublayers ?? [] { if border.name == "rightBorderLayer" { border.frame = CGRect(x: self.frame.size.width - border.frame.width, y: 0, width : border.frame.width, height :self.frame.size.height) } } case UnsafeMutableRawPointer(bitPattern: 3333): for border in self.layer.sublayers ?? [] { if border.name == "bottomBorderLayer" { border.frame = CGRect(x: 0, y: self.frame.size.height - border.frame.height,width : self.frame.size.width,height: border.frame.height) } } case UnsafeMutableRawPointer(bitPattern: 4444): for border in self.layer.sublayers ?? [] { if border.name == "leftBorderLayer" { border.frame = CGRect(x:0, y:0,width : border.frame.width, height : self.frame.size.height) } } default: break } } } func removePreviouslyAddedLayer(name : String) { if self.layer.sublayers?.count ?? 0 > 0 { self.layer.sublayers?.forEach { if $0.name == name { $0.removeFromSuperlayer() } } } } }

目标 C

创建 UIView 的类别类

UIView + Border.h

#import <UIKit/UIKit.h> #import <Foundation/Foundation.h> @interface UIView (Border) @property (nonatomic) IBInspectable UIColor *topLineColor; @property (nonatomic) IBInspectable CGFloat topLineWidth; @property (nonatomic) IBInspectable UIColor *bottomLineColor; @property (nonatomic) IBInspectable CGFloat bottomLineWidth; @property (nonatomic) IBInspectable UIColor *rightLineColor; @property (nonatomic) IBInspectable CGFloat rightLineWidth; @property (nonatomic) IBInspectable UIColor *leftLineColor; @property (nonatomic) IBInspectable CGFloat leftLineWidth; - (void)addBottomBorderWithColor: (UIColor *) color andWidth:(CGFloat) borderWidth; - (void)addLeftBorderWithColor: (UIColor *) color andWidth:(CGFloat) borderWidth; - (void)addRightBorderWithColor: (UIColor *) color andWidth:(CGFloat) borderWidth; - (void)addTopBorderWithColor: (UIColor *) color andWidth:(CGFloat) borderWidth; @end

UIView + Border.m

static void *topBorderContext = &topBorderContext; static void *bottomBorderContext = &bottomBorderContext; static void *leftBorderContext = &leftBorderContext; static void *rightBorderContext = &rightBorderContext; static char bottomLineColorKey,topLineColorKey,rightLineColorKey,leftLineColorKey; @implementation UIView(Utility) @dynamic borderColor,borderWidth,cornerRadius,bottomLineWidth,topLineWidth,rightLineWidth,leftLineWidth; -(void)setBorderColor:(UIColor *)borderColor{ [self.layer setBorderColor:borderColor.CGColor]; } -(void)setBorderWidth:(CGFloat)borderWidth{ [self.layer setBorderWidth:borderWidth]; } -(void)setCornerRadius:(CGFloat)cornerRadius{ [self.layer setCornerRadius:cornerRadius]; } // for Bottom Line - (UIColor *)bottomLineColor { return objc_getAssociatedObject(self, &bottomLineColorKey); } - (void)setBottomLineColor:(UIColor *)bottomLineColor { objc_setAssociatedObject(self, &bottomLineColorKey, bottomLineColor, OBJC_ASSOCIATION_RETAIN_NONATOMIC); } -(void)setBottomLineWidth:(CGFloat)bottomLineWidth { [self addBottomBorderWithColor:[self bottomLineColor] andWidth:bottomLineWidth]; } // for top Line - (UIColor *)topLineColor { return objc_getAssociatedObject(self, &topLineColorKey); } - (void)setTopLineColor:(UIColor *)topLineColor { objc_setAssociatedObject(self, &topLineColorKey, topLineColor, OBJC_ASSOCIATION_RETAIN_NONATOMIC); } - (void)setTopLineWidth:(CGFloat)topLineWidth{ [self addTopBorderWithColor:[self topLineColor] andWidth:topLineWidth]; } // for right Line - (UIColor *)rightLineColor { return objc_getAssociatedObject(self, &rightLineColorKey); } -(void)setRightLineColor:(UIColor *)rightLineColor { objc_setAssociatedObject(self, &rightLineColorKey, rightLineColor, OBJC_ASSOCIATION_RETAIN_NONATOMIC); } -(void)setRightLineWidth:(CGFloat)rightLineWidth{ [self addRightBorderWithColor:[self rightLineColor] andWidth:rightLineWidth]; } // for left Line -(UIColor *)leftLineColor { return objc_getAssociatedObject(self, &leftLineColorKey); } -(void)setLeftLineColor:(UIColor *)leftLineColor{ objc_setAssociatedObject(self, &leftLineColorKey, leftLineColor, OBJC_ASSOCIATION_RETAIN_NONATOMIC); } -(void)setLeftLineWidth:(CGFloat)leftLineWidth{ [self addLeftBorderWithColor:[self leftLineColor] andWidth:leftLineWidth]; } - (void)addTopBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth { dispatch_async(dispatch_get_main_queue(), ^{ CALayer *border = [CALayer layer]; border.name = @"topBorderLayer"; [self removePreviouslyAddedLayer:border.name]; border.backgroundColor = color.CGColor; border.frame = CGRectMake(0, 0, self.frame.size.width, borderWidth); [self.layer addSublayer:border]; [self addObserver:self forKeyPath: @"bounds" options:NSKeyValueObservingOptionNew context:topBorderContext]; }); } - (void)addBottomBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth { dispatch_async(dispatch_get_main_queue(), ^{ CALayer *border = [CALayer layer]; border.name = @"bottomBorderLayer"; [self removePreviouslyAddedLayer:border.name]; border.backgroundColor = color.CGColor; border.frame = CGRectMake(0, self.frame.size.height - borderWidth, self.frame.size.width, borderWidth); [self.layer addSublayer:border]; [self addObserver:self forKeyPath: @"bounds" options:NSKeyValueObservingOptionNew context:bottomBorderContext]; }); } - (void)addLeftBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth { dispatch_async(dispatch_get_main_queue(), ^{ CALayer *border = [CALayer layer]; border.name = @"leftBorderLayer"; [self removePreviouslyAddedLayer:border.name]; border.backgroundColor = color.CGColor; border.frame = CGRectMake(0, 0, borderWidth, self.frame.size.height); [self.layer addSublayer:border]; [self addObserver:self forKeyPath: @"bounds" options:NSKeyValueObservingOptionNew context:leftBorderContext]; }); } - (void)addRightBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth { dispatch_async(dispatch_get_main_queue(), ^{ CALayer *border = [CALayer layer]; border.name = @"rightBorderLayer"; [self removePreviouslyAddedLayer:border.name]; border.backgroundColor = color.CGColor; border.frame = CGRectMake(self.frame.size.width - borderWidth, 0, borderWidth, self.frame.size.height); [self.layer addSublayer:border]; [self addObserver:self forKeyPath: @"bounds" options:NSKeyValueObservingOptionNew context:rightBorderContext]; }); } - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context { if (context == topBorderContext) { for (CALayer *border in self.layer.sublayers) { if ([border.name isEqualToString:@"topBorderLayer"]) { [border setFrame:CGRectMake(0, 0, self.frame.size.width, border.frame.size.height)]; } } } else if (context == bottomBorderContext) { for (CALayer *border in self.layer.sublayers) { if ([border.name isEqualToString:@"bottomBorderLayer"]) { [border setFrame:CGRectMake(0, self.frame.size.height - border.frame.size.height, self.frame.size.width, border.frame.size.height)]; } } } else if (context == leftBorderContext) { for (CALayer *border in self.layer.sublayers) { if ([border.name isEqualToString:@"leftBorderLayer"]) { [border setFrame:CGRectMake(0, 0, border.frame.size.width, self.frame.size.height)]; } } } else if (context == rightBorderContext) { for (CALayer *border in self.layer.sublayers) { if ([border.name isEqualToString:@"rightBorderLayer"]) { [border setFrame:CGRectMake(self.frame.size.width - border.frame.size.width, 0, border.frame.size.width, self.frame.size.height)]; } } } else { [super observeValueForKeyPath:keyPath ofObject:object change:change context:context]; } } - (void)removePreviouslyAddedLayer:(NSString *)name { if (self.layer.sublayers.count > 0) { for (CALayer *layer in self.layer.sublayers) { if ([layer.name isEqualToString:name]) { [layer removeFromSuperlayer]; } } } } @end

从故事板中选择任何控件，然后显示属性检查器(右侧) ，您将看到下图示例。(注意: 边框只在运行时出现。)

现在你可以设置边框的颜色和宽度。

小开

带边框宽度和颜色的 Swift 4扩展。效果很好！

@IBDesignable final class SideBorders: UIView { @IBInspectable var topColor: UIColor = UIColor.clear @IBInspectable var topWidth: CGFloat = 0 @IBInspectable var rightColor: UIColor = UIColor.clear @IBInspectable var rightWidth: CGFloat = 0 @IBInspectable var bottomColor: UIColor = UIColor.clear @IBInspectable var bottomWidth: CGFloat = 0 @IBInspectable var leftColor: UIColor = UIColor.clear @IBInspectable var leftWidth: CGFloat = 0 override func draw(_ rect: CGRect) { let topBorder = CALayer() topBorder.backgroundColor = topColor.cgColor topBorder.frame = CGRect(x: 0, y: 0, width: self.frame.size.width, height: topWidth) self.layer.addSublayer(topBorder) let rightBorder = CALayer() rightBorder.backgroundColor = rightColor.cgColor rightBorder.frame = CGRect(x: self.frame.size.width - rightWidth, y: 0, width: rightWidth, height: self.frame.size.height) self.layer.addSublayer(rightBorder) let bottomBorder = CALayer() bottomBorder.backgroundColor = bottomColor.cgColor bottomBorder.frame = CGRect(x: 0, y: self.frame.size.height - bottomWidth, width: self.frame.size.width, height: bottomWidth) self.layer.addSublayer(bottomBorder) let leftBorder = CALayer() leftBorder.backgroundColor = leftColor.cgColor leftBorder.frame = CGRect(x: 0, y: self.frame.size.height - leftWidth, width: self.frame.size.width, height: leftWidth) self.layer.addSublayer(leftBorder) }

}

小开

Swift 4

基于 https://stackoverflow.com/a/32513578/5391914

import UIKit enum ViewBorder: String { case Left = "borderLeft" case Right = "borderRight" case Top = "borderTop" case Bottom = "borderBottom" } extension UIView { func addBorder(vBorders: [ViewBorder], color: UIColor, width: CGFloat) { vBorders.forEach { vBorder in let border = CALayer() border.backgroundColor = color.cgColor border.name = vBorder.rawValue switch vBorder { case .Left: border.frame = CGRect(x: 0, y: 0, width: width, height: self.frame.size.height) case .Right: border.frame = CGRect(x:self.frame.size.width - width, y: 0, width: width, height: self.frame.size.height) case .Top: border.frame = CGRect(x: 0, y: 0, width: self.frame.size.width, height: width) case .Bottom: border.frame = CGRect(x: 0, y: self.frame.size.height - width , width: self.frame.size.width, height: width) } self.layer.addSublayer(border) } } }

小开

Swift 4

基于: https://stackoverflow.com/a/32821607/9980800

UIView + 边框

extension UIView { enum ViewBorder: String { case left, right, top, bottom } func add(Border border: ViewBorder, withColor color: UIColor = UIColor.lightGray, andWidth width: CGFloat = 1.0) { let borderView = UIView() borderView.backgroundColor = color borderView.translatesAutoresizingMaskIntoConstraints = false self.addSubview(borderView) NSLayoutConstraint.activate(getConstrainsFor(forView: borderView, WithBorderType: border, andWidth: width)) } private func getConstrainsFor(forView borderView: UIView, WithBorderType border: ViewBorder, andWidth width: CGFloat) -> [NSLayoutConstraint] { let height = borderView.heightAnchor.constraint(equalToConstant: width) let widthAnchor = borderView.widthAnchor.constraint(equalToConstant: width) let leading = borderView.leadingAnchor.constraint(equalTo: self.leadingAnchor) let trailing = borderView.trailingAnchor.constraint(equalTo: self.trailingAnchor) let top = borderView.topAnchor.constraint(equalTo: self.topAnchor) let bottom = borderView.bottomAnchor.constraint(equalTo: self.bottomAnchor) switch border { case .bottom: return [bottom, leading, trailing, height] case .top: return [top, leading, trailing, height] case .left: return [top, bottom, leading, widthAnchor] case .right: return [top, bottom, trailing, widthAnchor] } }

}

用法:-

class ViewController: UIViewController { @IBOutlet weak var sampleView: UIView! override func viewDidLoad() { super.viewDidLoad() // Do any additional setup after loading the view, typically from a nib. sampleView.add(Border: .bottom) } override func didReceiveMemoryWarning() { super.didReceiveMemoryWarning() // Dispose of any resources that can be recreated. } }

小开

如果使用约束(因此没有框架大小) ，那么可以添加具有所需约束的边框视图

// MARK: - Add a border to one side of a view public enum BorderSide { case top, bottom, left, right } extension UIView { public func addBorder(side: BorderSide, color: UIColor, width: CGFloat) { let border = UIView() border.translatesAutoresizingMaskIntoConstraints = false border.backgroundColor = color self.addSubview(border) let topConstraint = topAnchor.constraint(equalTo: border.topAnchor) let rightConstraint = trailingAnchor.constraint(equalTo: border.trailingAnchor) let bottomConstraint = bottomAnchor.constraint(equalTo: border.bottomAnchor) let leftConstraint = leadingAnchor.constraint(equalTo: border.leadingAnchor) let heightConstraint = border.heightAnchor.constraint(equalToConstant: width) let widthConstraint = border.widthAnchor.constraint(equalToConstant: width) switch side { case .top: NSLayoutConstraint.activate([leftConstraint, topConstraint, rightConstraint, heightConstraint]) case .right: NSLayoutConstraint.activate([topConstraint, rightConstraint, bottomConstraint, widthConstraint]) case .bottom: NSLayoutConstraint.activate([rightConstraint, bottomConstraint, leftConstraint, heightConstraint]) case .left: NSLayoutConstraint.activate([bottomConstraint, leftConstraint, topConstraint, widthConstraint]) } } }

然后把它设置成下面这样

myButton.addBorder(side: .left, color: UIColor.lightGray, width: 1)

(灵感来自这个答案)

小开

Swift 4的解决方案

let bottomBorder = CALayer() bottomBorder.frame = CGRect(x: 0.0, y: calendarView.frame.size.height-1, width: calendarView.frame.width, height: 1.0) bottomBorder.backgroundColor = #colorLiteral(red: 0.8039215803, green: 0.8039215803, blue: 0.8039215803, alpha: 1) calendarView.layer.addSublayer(bottomBorder)

背景颜色浅灰色。如果需要可以更改颜色。

小开

与两个扩展一起使用，方法返回 CALayer，所以你可以重用它来更新帧。

enum Border: Int { case top = 0 case bottom case right case left } extension UIView { func addBorder(for side: Border, withColor color: UIColor, borderWidth: CGFloat) -> CALayer { let borderLayer = CALayer() borderLayer.backgroundColor = color.cgColor let xOrigin: CGFloat = (side == .right ? frame.width - borderWidth : 0) let yOrigin: CGFloat = (side == .bottom ? frame.height - borderWidth : 0) let width: CGFloat = (side == .right || side == .left) ? borderWidth : frame.width let height: CGFloat = (side == .top || side == .bottom) ? borderWidth : frame.height borderLayer.frame = CGRect(x: xOrigin, y: yOrigin, width: width, height: height) layer.addSublayer(borderLayer) return borderLayer } } extension CALayer { func updateBorderLayer(for side: Border, withViewFrame viewFrame: CGRect) { let xOrigin: CGFloat = (side == .right ? viewFrame.width - frame.width : 0) let yOrigin: CGFloat = (side == .bottom ? viewFrame.height - frame.height : 0) let width: CGFloat = (side == .right || side == .left) ? frame.width : viewFrame.width let height: CGFloat = (side == .top || side == .bottom) ? frame.height : viewFrame.height frame = CGRect(x: xOrigin, y: yOrigin, width: width, height: height) } }

小开

extension UIView { func addBottomLine(color: UIColor, height: CGFloat) { let bottomView = UIView(frame: CGRect(x: 0, y: self.frame.height - 1, width: self.frame.width, height: height)) bottomView.translatesAutoresizingMaskIntoConstraints = false bottomView.autoresizingMask = .flexibleWidth bottomView.backgroundColor = color self.addSubview(bottomView) } }

小开

extension UIView{ enum side:String { case top case bottom case left case right } func addBorder(side:side,color:UIColor,width:CGFloat) { let border = CALayer() border.backgroundColor = color.cgColor switch side { case .top: border.frame = CGRect(x: 0, y: 0, width: self.frame.size.width, height: width) case .bottom: border.frame = CGRect(x: 0, y: self.frame.size.height - width, width: self.frame.size.width, height: width) case .left: border.frame = CGRect(x: 0, y: 0, width: width, height: self.frame.size.height) case .right: border.frame = CGRect(x: self.frame.size.width - width, y: 0, width: width, height: self.frame.size.height) } self.layer.addSublayer(border) }

}

底部边框 UIView? ？

Swift 3