UIView bottom border?

To a UIScrollView *toScrollView (which is the width of the screen), I want to add a gray bottom border (exactly like that of the to-field of the compose view of the iPhone's native Messages app).

To achieve this, I followed https://stackoverflow.com/questions/3330378/cocoa-touch-how-to-change-uiviews-border-color-and-thickness/3330397#3330397 and just covered the top border with the custom UINavigationBar and made the toScrollView's x-coordinate -1 & width 322 so that the left & right borders are just off screen.

This looks fine, but it's sort of a hack, and I was wondering if there's a better way to do this.

- (void)viewDidLoad {
    [super viewDidLoad];

    // Add UINavigationBar *navigationBar at top.
    self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]
                                             initWithBarButtonSystemItem:UIBarButtonSystemItemCancel
                                             target:self action:@selector(cancelAction)];
    UINavigationBar *navigationBar = [[UINavigationBar alloc]
                                      initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, 44.0f)];
    navigationBar.items = [NSArray arrayWithObject:self.navigationItem];

    // Add UIScrollView *toScrollView below navigationBar.
    UIScrollView *toScrollView = [[UIScrollView alloc]
                                  initWithFrame:CGRectMake(-1.0f, 43.0f, 322.0f, 45.0f)];
    toScrollView.backgroundColor = [UIColor whiteColor];
    toScrollView.layer.borderColor = [UIColor colorWithWhite:0.8f alpha:1.0f].CGColor;
    toScrollView.layer.borderWidth = 1.0f;
    [self.view addSubview:toScrollView];
    [self.view addSubview:navigationBar]; // covers top of toScrollView
}

Instead of using a UIView, as @ImreKelényi suggests, you can use a 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];

Here is a more generalized Swift extension to create border for any UIView subclass:

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)
    }
}

Implemented in a category as below:

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

Swift 4

If you need a really adaptive solution (for all screen sizes), then this is it:

/**
* 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))
    }
}

You can add a separate UIView with 1 point height and gray background color to self.view and position it right below toScrollView.

> EDIT: Unless you have a good reason (want to use some services of UIView which are not offered by CALayer), you should use CALayer as @MattDiPasquale suggests. UIView has a greater overhead, which might not be a problem in most cases, but still, the other solution is more elegant.

Solution for Swift 4

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)

BackgroundColor lightGray. Change color if you need.

There is also improved code with remove border functionality. Based on confile answer.

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()
        }
    }
    
}

Update: 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()
        }
    }
    
}

Or, the most performance-friendly way is to overload drawRect, simply like that:

@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

The problem with these extension methods is that when the UIView/UIButton later adjusts it's size, you have no chance to change the CALayer's size to match the new size. Which will leave you with a misplaced border. I found it was better to subclass my UIButton, you could of course subclass other UIViews as well. Here is some code:

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)
    }
    
}

If you use constraints (and so don't have the frame sizes) then you can add a border view with the required constraints

// 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])
        }
    }
}

Then set it something like the below

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

(inspired by this answer)

Swift 3 version of Confile's answer:

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)
    }
}

Usage when using auto layout:

class CustomView: UIView {

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

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

Swift

Create UIView extension

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()
            }
        }
    }
   }
}

Objective C

Create category class of UIView

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

Usage :- Select any control from storyboard, then show attribute inspector (Right side) You will see below image Example.(Note : Border only appear at run time.)

Now You can set any side of border colour and width.

[![][1]][1] [1]: https://i.stack.imgur.com/fPR48.png

Swift 4

Based on 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)
        }
    }
}

Swift 4

Based on: https://stackoverflow.com/a/32821607/9980800

UIView+Border

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]
    }
}

}

Usage:-

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.
}
}

I wrote a general method that will add a border on whichever sides you wish in any UIView. You can define thickness, color, margins and zOrder for each side.

/*
 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];
    }
}

You don't have to add a layer for each border, just use a bezier path to draw them once.

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];

Swift 4/3

You can use this solution beneath. It works on UIBezierPaths which are lighter than layers, causing quick startup times. It is easy to use, see instructions beneath.

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()
        }
    }
}

1. Set your UIView's class to ResizeBorderView
2. Set the color and line width by using yourview.color and yourview.lineWidth in your viewDidAppear method
3. Set the edges, example: yourview.edges = [.right, .left] ([.all]) for all
4. Enjoy quick start and resizing borders

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)
 }

}

The most complete answer. https://github.com/oney/UIView-Border

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))

Swift 4 extension with border width and color. Works great!

@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)
}

}

Swift 5.1. Use with two extension, method return CALayer, so you would reuse it to update frames.

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)
    }
}

    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)
}

}