这是我发现的最简单的方法。这对我来说很有魔力。

UIView *titleSection = [[UIView alloc] initWithFrame:CGRectMake(0, 0, screenWidth, 100)];
[titleSection addSubview:titleSection];

UILabel *label = [[UILabel alloc] initWithFrame:CGRectInset(titleSection.frame, PADDING, 0)];
[titleSection addSubview:label];

对于多行文本，可以使用NSAttributedString设置左右边距。

NSMutableParagraphStyle *style =  [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
style.alignment = NSTextAlignmentJustified;
style.firstLineHeadIndent = 10.0f;
style.headIndent = 10.0f;
style.tailIndent = -10.0f;   

NSAttributedString *attrText = [[NSAttributedString alloc] initWithString:title attributes:@{ NSParagraphStyleAttributeName : style}];  

UILabel * label = [[UILabel alloc] initWithFrame:someFrame];
label.numberOfLines = 0;
label.attributedText = attrText;

以下是Swift 5采用的上述示例:

extension UILabel {
    func setMargins(margin: CGFloat = 10) {
        if let textString = self.text {
            var 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
        }
    }
}

Swift 3 &自动布局兼容版本:

class InsetLabel: UILabel {

    var insets = UIEdgeInsets()

    convenience init(insets: UIEdgeInsets) {
        self.init(frame: CGRect.zero)
        self.insets = insets
    }

    convenience init(dx: CGFloat, dy: CGFloat) {
        let insets = UIEdgeInsets(top: dy, left: dx, bottom: dy, right: dx)
        self.init(insets: insets)
    }

    override func drawText(in rect: CGRect) {
        super.drawText(in: UIEdgeInsetsInsetRect(rect, insets))
    }

    override var intrinsicContentSize: CGSize  {
        var size = super.intrinsicContentSize
        size.width += insets.left + insets.right
        size.height += insets.top + insets.bottom
        return size
    }
}

这里有一个快速的解决方案。只需在文件底部添加这个自定义类(或为其创建一个新文件)，并在创建标签时使用MyLabel而不是UILabel。

class MyLabel: UILabel{
    override func drawTextInRect(rect: CGRect) {
        super.drawTextInRect(UIEdgeInsetsInsetRect(rect, UIEdgeInsets(top: 0, left: 10, bottom: 0, right: 0)))
    }
}

这是我发现的最简单的方法。这对我来说很有魔力。

UIView *titleSection = [[UIView alloc] initWithFrame:CGRectMake(0, 0, screenWidth, 100)];
[titleSection addSubview:titleSection];

UILabel *label = [[UILabel alloc] initWithFrame:CGRectInset(titleSection.frame, PADDING, 0)];
[titleSection addSubview:label];

很多答案都缺少对sizeThatFits的重写。有了这个子类，你可以创建标签，设置填充，然后输入label。sizetofit()，瞧。

import UIKit

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

    override func drawTextInRect(rect: CGRect) {

        super.drawTextInRect(UIEdgeInsetsInsetRect(rect, padding))
    }

    override func sizeThatFits(size: CGSize) -> CGSize
    {

        var adjSize = super.sizeThatFits(size)
        adjSize.width += padding.left + padding.right
        adjSize.height += padding.top + padding.bottom

        return adjSize
    }
}