Untuk a UIScrollView *toScrollView(yang merupakan lebar layar), saya ingin menambahkan batas bawah abu-abu (persis seperti pada bidang-bidang dari tampilan penulisan aplikasi Pesan asli iPhone).

Untuk mencapai ini, saya mengikuti Cocoa Touch: Bagaimana Mengganti Warna Dan Ketebalan Perbatasan UIView? dan hanya menutupi batas atas dengan kebiasaan UINavigationBardan membuat toScrollViewkoordinat x -1 & lebar 322 sehingga batas kiri & kanan lepas layar.

Ini terlihat baik-baik saja, tapi ini semacam peretasan, dan saya bertanya-tanya apakah ada cara yang lebih baik untuk melakukan ini.

- (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
}

Alih-alih menggunakan UIView, seperti yang disarankan oleh @ ImreKelényi, Anda dapat menggunakan 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];

Berikut ini adalah ekstensi Swift yang lebih umum untuk membuat batas untuk setiap UIViewsubkelas:

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)
  }
}

Cepat 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)
    }
}

Diimplementasikan dalam kategori seperti di bawah ini:

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 + Perbatasan.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

Cepat 4

Jika Anda membutuhkan solusi yang benar-benar adaptif (untuk semua ukuran layar), ini dia:

/**
* 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))
    }
}

Anda dapat menambahkan terpisah UIViewdengan ketinggian 1 titik dan warna latar belakang abu-abu ke self.viewdan posisikan tepat di bawah toScrollView.

EDIT: Kecuali Anda memiliki alasan yang bagus (ingin menggunakan beberapa layanan UIView yang tidak ditawarkan oleh CALayer), Anda harus menggunakan CALayer seperti yang disarankan oleh @MattDiPasquale . UIView memiliki overhead yang lebih besar, yang mungkin tidak menjadi masalah dalam banyak kasus, tetapi tetap saja, solusi lain lebih elegan.

Solusi untuk 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. Ubah warna jika Anda perlu.

Ada juga kode yang ditingkatkan dengan menghapus fungsi perbatasan. Berdasarkan jawaban confile .

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()
        }
    }

}

Pembaruan: 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()
        }
    }

}

Masalah dengan metode ekstensi ini adalah bahwa ketika UIView / UIButton kemudian menyesuaikan ukurannya, Anda tidak memiliki kesempatan untuk mengubah ukuran CALayer agar sesuai dengan ukuran baru. Yang akan membuat Anda dengan perbatasan salah tempat. Saya menemukan lebih baik untuk subkelas UIButton saya, Anda tentu saja dapat subkelas UIViews lain juga. Ini beberapa kode:

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)
    }

}

Atau, cara yang paling ramah-kinerja adalah dengan membebani drawRect, cukup seperti itu:

@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

Jawaban Swile 3 versi jawaban:

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)
    }
}

Penggunaan saat menggunakan tata letak otomatis:

class CustomView: UIView {

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

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

Jika Anda menggunakan batasan (dan karena itu tidak memiliki ukuran bingkai) maka Anda dapat menambahkan tampilan perbatasan dengan kendala yang diperlukan

// 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])
        }
    }
}

Kemudian atur seperti di bawah ini

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

(terinspirasi oleh jawaban ini )

Cepat

Buat ekstensi UIView

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()
            }
        }
    }
   }
}

Tujuan C

Buat kelas kategori 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

Penggunaan: - Pilih kontrol apa saja dari storyboard, lalu tunjukkan inspektur atribut (Sisi kanan) Anda akan melihat contoh gambar di bawah ini (Catatan: Perbatasan hanya muncul pada saat run time.)

Sekarang Anda dapat mengatur sisi warna dan lebar perbatasan.

Saya menulis metode umum yang akan menambahkan batas pada sisi mana pun yang Anda inginkan UIView. Anda dapat menentukan ketebalan, warna, margin dan zOrderuntuk setiap sisi.

/*
 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];
    }
}

Anda tidak perlu menambahkan layer untuk setiap perbatasan, cukup gunakan jalur bezier untuk menggambar mereka sekali.

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];