详细阐述Mundi的回答。

例如，在UIView中嵌入一个标签，并通过自动布局强制填充。例子:

概述:

创建一个UIView(面板)，并设置它的外观。 创建一个UILabel并将其添加到面板中。 添加约束以强制填充。 将面板添加到视图层次结构中，然后定位面板。

细节:

创建面板视图。 let panel = UIView() 面板。backgroundColor = .green panel.layer.cornerRadius = 12 创建标签，将其作为子视图添加到面板。 let label = UILabel() panel.addSubview(标签) 在标签的边缘和面板之间添加约束。这迫使面板与标签保持一定距离。也就是说,“填充”。

编辑:手工完成所有这些是超级乏味、冗长和容易出错的。我建议你从GitHub中选择一个自动布局包装器或自己写一个

label.panel.translatesAutoresizingMaskIntoConstraints = false
label.topAnchor.constraint(equalTo: panel.topAnchor,
    constant: vPadding).isActive = true
label.bottomAnchor.constraint(equalTo: panel.bottomAnchor,
    constant: -vPadding).isActive = true
label.leadingAnchor.constraint(equalTo: panel.leadingAnchor,
    constant: hPadding).isActive = true
label.trailingAnchor.constraint(equalTo: panel.trailingAnchor,
    constant: -hPadding).isActive = true

label.textAlignment = .center

将面板添加到视图层次结构中，然后添加定位约束。例如，拥抱tableViewCell的右侧，如示例图像中所示。

注意:您只需要添加位置约束，而不是尺寸约束:Auto Layout将基于标签的intrinsicContentSize和前面添加的约束来解决布局问题。

hostView.addSubview(panel)
panel.translatesAutoresizingMaskIntoConstraints = false
panel.trailingAnchor.constraint(equalTo: hostView.trailingAnchor,
    constant: -16).isActive = true
panel.centerYAnchor.constraint(equalTo: hostView.centerYAnchor).isActive = true

类似于其他答案，但使用func类来动态地设置填充:

class UILabelExtendedView: UILabel
{
    var topInset: CGFloat = 4.0
    var bottomInset: CGFloat = 4.0
    var leftInset: CGFloat = 8.0
    var rightInset: CGFloat = 8.0

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

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

    func setPadding(top: CGFloat, left: CGFloat, bottom: CGFloat, right: CGFloat){
        self.topInset = top
        self.bottomInset = bottom
        self.leftInset = left
        self.rightInset = right
        let insets: UIEdgeInsets = UIEdgeInsets(top: top, left: left, bottom: bottom, right: right)
        super.drawText(in: UIEdgeInsetsInsetRect(self.frame, insets))
    }
}

一个实用的解决方案是添加与主标签高度和颜色相同的空白标签。将主标签的前导/尾距设置为零，对齐垂直中心，并设置所需的宽度。

如果你想使用UILabel

class UILabel : UIKit.UILabel {
    var insets = 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: -insets.top,
                                          left: -insets.left,
                                          bottom: -insets.bottom,
                                          right: -insets.right)
        return textRect.inset(by: invertedInsets)
    }

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

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)
    }
}

我的解决方案与人们回答的类似，但添加了sizeThatFits来帮助UIKit找出正确的大小。

class InsetLabel : UILabel {
    @objc var textInsets: UIEdgeInsets = .zero

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

    override func sizeThatFits(_ size: CGSize) -> CGSize {
        var s = super.sizeThatFits(CGSize(width: size.width - (textInsets.left + textInsets.right), height: size.height - (textInsets.top + textInsets.bottom)))
        s.height += textInsets.top + textInsets.bottom
        return s
    }
}