如果你不想或需要在Storyboard中使用@IBInspectable / @IBDesignable UILabel(我认为那些渲染太慢了)，那么使用UIEdgeInsets而不是4个不同的cgfloat会更干净。

Swift 4.2的代码示例:

class UIPaddedLabel: UILabel {
    var padding = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)

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

    public override var intrinsicContentSize: CGSize {
        let size = super.intrinsicContentSize
        return CGSize(width: size.width + padding.left + padding.right,
                      height: size.height + padding.top + padding.bottom)
    }
}

如果你不想或需要在Storyboard中使用@IBInspectable / @IBDesignable UILabel(我认为那些渲染太慢了)，那么使用UIEdgeInsets而不是4个不同的cgfloat会更干净。

Swift 4.2的代码示例:

class UIPaddedLabel: UILabel {
    var padding = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)

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

    public override var intrinsicContentSize: CGSize {
        let size = super.intrinsicContentSize
        return CGSize(width: size.width + padding.left + padding.right,
                      height: size.height + padding.top + padding.bottom)
    }
}

斯威夫特 4+

let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.firstLineHeadIndent = 10

// Swift 4.2++
label.attributedText = NSAttributedString(string: "Your text", attributes: [NSAttributedString.Key.paragraphStyle: paragraphStyle])

// Swift 4.1--
label.attributedText = NSAttributedString(string: "Your text", attributes: [NSAttributedStringKey.paragraphStyle: paragraphStyle])

如果你想坚持使用UILabel，而不子类化它，Mundi已经给了你一个明确的解决方案。

如果你想避免用UIView来包装UILabel，你可以使用UITextView来支持UIEdgeInsets (padding)或者子类UILabel来支持UIEdgeInsets。

使用UITextView只需要提供insets (Objective-C):

textView.textContainerInset = UIEdgeInsetsMake(10, 0, 10, 0);

另外，如果你子类化UILabel，这种方法的一个例子是重写drawTextInRect方法 (objective - c)

- (void)drawTextInRect:(CGRect)uiLabelRect {
    UIEdgeInsets myLabelInsets = {10, 0, 10, 0};
    [super drawTextInRect:UIEdgeInsetsInsetRect(uiLabelRect, myLabelInsets)];
}

您还可以为您的新子类UILabel提供带有insets变量的TOP, LEFT, BOTTOM和RIGHT。

一个示例代码可以是:

In .h (Objective-C)

float topInset, leftInset,bottomInset, rightInset;

在。m (Objective-C)中

- (void)drawTextInRect:(CGRect)uiLabelRect {
    [super drawTextInRect:UIEdgeInsetsInsetRect(uiLabelRect, UIEdgeInsetsMake(topInset,leftInset,bottomInset,rightInset))];
}

从我所看到的，似乎你必须在子类化UILabel时重写它的intrinsicContentSize。

所以你应该像这样重写intrinsicContentSize:

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

并添加以下方法来编辑您的嵌入，而不是单独编辑它们:

- (void) setContentEdgeInsets:(UIEdgeInsets)edgeInsets {
    topInset = edgeInsets.top;
    leftInset = edgeInsets.left;
    rightInset = edgeInsets.right;
    bottomInset = edgeInsets.bottom;
    [self invalidateIntrinsicContentSize] ;
}

它将更新UILabel的大小，以匹配边缘插入并覆盖您提到的多行需求。

经过搜索，我找到了一个IPInsetLabel的Gist。如果这些方法都不起作用，你可以尝试一下。

关于这件事，还有一个类似的问题(重复)。 有关可用解决方案的完整列表，请参阅以下答案:UILabel文本边距

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)

如果在应用填充时遇到文本修剪问题，请使用此代码。

@IBDesignable class PaddingLabel: UILabel {

    @IBInspectable var topInset: CGFloat = 5.0
    @IBInspectable var bottomInset: CGFloat = 5.0
    @IBInspectable var leftInset: CGFloat = 5.0
    @IBInspectable var rightInset: CGFloat = 5.0

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

    override var intrinsicContentSize: CGSize {
        var intrinsicSuperViewContentSize = super.intrinsicContentSize
        let textWidth = frame.size.width - (self.leftInset + self.rightInset)
        let newSize = self.text!.boundingRect(with: CGSize(textWidth, CGFloat.greatestFiniteMagnitude), options: NSStringDrawingOptions.usesLineFragmentOrigin, attributes: [NSFontAttributeName: self.font], context: nil)
        intrinsicSuperViewContentSize.height = ceil(newSize.size.height) + self.topInset + self.bottomInset
        return intrinsicSuperViewContentSize
    }
}

extension CGSize{
    init(_ width:CGFloat,_ height:CGFloat) {
        self.init(width:width,height:height)
    }
}