简单的填充:

import UIKit

    class NewLabel: UILabel {

        override func textRectForBounds(bounds: CGRect, limitedToNumberOfLines numberOfLines: Int) -> CGRect {

            return CGRectInset(self.bounds, CGFloat(15.0), CGFloat(15.0))
        }

        override func drawRect(rect: CGRect) {

            super.drawTextInRect(CGRectInset(self.bounds,CGFloat(5.0), CGFloat(5.0)))
        }

    }

斯威夫特 4+

class EdgeInsetLabel: UILabel {
    var textInsets = UIEdgeInsets.zero {
        didSet { invalidateIntrinsicContentSize() }
    }

    override func textRect(forBounds bounds: CGRect, limitedToNumberOfLines numberOfLines: Int) -> CGRect {
        let textRect = super.textRect(forBounds: bounds, limitedToNumberOfLines: numberOfLines)
        let invertedInsets = UIEdgeInsets(top: -textInsets.top,
                                          left: -textInsets.left,
                                          bottom: -textInsets.bottom,
                                          right: -textInsets.right)
        return textRect.inset(by: invertedInsets)
    }

    override func drawText(in rect: CGRect) {
        super.drawText(in: rect.inset(by: textInsets))
    }
}

用法:

let label = EdgeInsetLabel()
label.textInsets = UIEdgeInsets(top: 2, left: 6, bottom: 2, right: 6)

只需使用自动布局:

let paddedWidth = myLabel.intrinsicContentSize.width + 2 * padding
myLabel.widthAnchor.constraint(equalToConstant: paddedWidth).isActive = true

完成了。

objective - c

基于Tai Le的回答，它在一个Interface Builder Designable中实现了这个特性，下面是Objective-C版本。

把这个放在YourLabel.h文件中:

@interface YourLabel : UILabel

@property IBInspectable CGFloat topInset;
@property IBInspectable CGFloat bottomInset;
@property IBInspectable CGFloat leftInset;
@property IBInspectable CGFloat rightInset;

@end

这个会放在yourlabel。m文件中:

IB_DESIGNABLE

@implementation YourLabel

#pragma mark - Super

- (instancetype)initWithCoder:(NSCoder *)aDecoder {
    self = [super initWithCoder:aDecoder];
    if (self) {
        self.topInset = 0;
        self.bottomInset = 0;
        self.leftInset = 0;
        self.rightInset = 0;
    }
    return self;
}

- (void)drawTextInRect:(CGRect)rect {
    UIEdgeInsets insets = UIEdgeInsetsMake(self.topInset, self.leftInset, self.bottomInset, self.rightInset);
    [super drawTextInRect:UIEdgeInsetsInsetRect(rect, insets)];
}

- (CGSize)intrinsicContentSize {
    
    CGSize size = [super intrinsicContentSize];
    return CGSizeMake(size.width + self.leftInset + self.rightInset,
                      size.height + self.topInset + self.bottomInset);
}

@end

然后，在XIB文件或故事板中指定类后，您可以直接在Interface Builder中修改YourLabel嵌入，嵌入的默认值为零。

没有故事板:

class PaddingLabel: UILabel {

    var topInset: CGFloat
    var bottomInset: CGFloat
    var leftInset: CGFloat
    var rightInset: CGFloat

    required init(withInsets top: CGFloat, _ bottom: CGFloat,_ left: CGFloat,_ right: CGFloat) {
        self.topInset = top
        self.bottomInset = bottom
        self.leftInset = left
        self.rightInset = right
        super.init(frame: CGRect.zero)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func drawText(in rect: CGRect) {
        let insets = UIEdgeInsets(top: topInset, left: leftInset, bottom: bottomInset, right: rightInset)
        super.drawText(in: UIEdgeInsetsInsetRect(rect, insets))
    }

    override var intrinsicContentSize: CGSize {
        get {
            var contentSize = super.intrinsicContentSize
            contentSize.height += topInset + bottomInset
            contentSize.width += leftInset + rightInset
            return contentSize
        }
    }
}

用法:

let label = PaddingLabel(8, 8, 16, 16)
label.font = .boldSystemFont(ofSize: 16)
label.text = "Hello World"
label.backgroundColor = .black
label.textColor = .white
label.textAlignment = .center
label.layer.cornerRadius = 8
label.clipsToBounds = true
label.sizeToFit()

view.addSubview(label)

结果:

使用UILabel扩展的Swift 5示例

使用下面的代码，设置你的边距就像label. setmargin(15)一样简单。

extension UILabel {
    func setMargins(_ margin: CGFloat = 10) {
        if let textString = self.text {
            let paragraphStyle = NSMutableParagraphStyle()
            paragraphStyle.firstLineHeadIndent = margin
            paragraphStyle.headIndent = margin
            paragraphStyle.tailIndent = -margin
            let attributedString = NSMutableAttributedString(string: textString)
            attributedString.addAttribute(.paragraphStyle, value: paragraphStyle, range: NSRange(location: 0, length: attributedString.length))
            attributedText = attributedString
        }
    }
}