ios UIView 底部边框？

UIView bottom border?

提问by ma11hew28

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).

对于 a UIScrollView *toScrollView（屏幕的宽度），我想添加一个灰色的底部边框（与 iPhone 的本机消息应用程序的撰写视图的 to 字段完全一样）。

To achieve this, I followed Cocoa Touch: How To Change UIView's Border Color And Thickness?and just covered the top border with the custom UINavigationBarand made the toScrollView's x-coordinate -1 & width 322 so that the left & right borders are just off screen.

为了实现这一点，我遵循了Cocoa Touch：如何更改 UIView 的边框颜色和厚度？并用自定义覆盖顶部边框UINavigationBar并使toScrollViewx 坐标 -1 和宽度为 322，以便左右边框刚好在屏幕外。

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

这看起来不错，但它有点像黑客，我想知道是否有更好的方法来做到这一点。

- (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
}

回答by ma11hew28

Instead of using a UIView, as @ImreKelényi suggests, you can use a CALayer:

如果不使用的UIView，如@ImreKelényi建议，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];

回答by confile

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

这是一个更通用的 Swift 扩展，用于为任何子UIView类创建边框：

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

斯威夫特 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)
    }
}

回答by Daniel Conde Marin

Implemented in a category as below:

在一个类别中实现，如下所示：

UIButton+Border.h:

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:

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

回答by Alexander Volkov

Swift 4

斯威夫特 4

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

如果您需要一个真正自适应的解决方案（适用于所有屏幕尺寸），那么就是这样：

/**
* 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))
    }
}

回答by Imre Kelényi

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

您可以添加一个单独的UIView1点高度和灰色的背景色self.view和右侧下方位置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.

编辑：除非你有充分的理由（想使用一些 CALayer 不提供的 UIView 服务），否则你应该像@MattDiPasquale 建议的那样使用 CALayer 。UIView 有更大的开销，这在大多数情况下可能不是问题，但是，另一种解决方案更优雅。

回答by oscar castellon

Solution for Swift 4

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)

BackgroundColor lightGray. Change color if you need.

背景颜色浅灰色。如果需要，更改颜色。

回答by Vladimirs Matusevics

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

还有带有移除边框功能的改进代码。基于配置文件答案。

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

更新：斯威夫特 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()
        }
    }

}

回答by Siamaster

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:

这些扩展方法的问题在于，当 UIView/UIButton 稍后调整其大小时，您没有机会更改 CALayer 的大小以匹配新大小。这会给你留下一个错位的边界。我发现子类化我的 UIButton 更好，当然你也可以子类化其他 UIViews。这是一些代码：

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)
    }

}

回答by iago849

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

或者，对性能最友好的方法是重载 drawRect，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

回答by spogebob92

Swift 3 version of Confile's answer:

Swift 3 版本的 Confile 答案：

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:

使用自动布局时的用法：

class CustomView: UIView {

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

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