我有一个UILabel,我想在顶部和底部添加空格。在限制最小高度的情况下,我将其修改为:

为了做到这一点,我使用了:

override func drawTextInRect(rect: CGRect) {
    var insets: UIEdgeInsets = UIEdgeInsets(top: 0.0, left: 10.0, bottom: 0.0, right: 10.0)
    super.drawTextInRect(UIEdgeInsetsInsetRect(rect, insets))
}

但我必须找到不同的方法,因为如果我写了超过两行,问题是一样的:


当前回答

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))
    }
}

其他回答

就像其他答案一样,但它修复了一个bug:

当标签。宽度由自动布局控制,有时文本会被裁剪。

@IBDesignable
class InsetLabel: UILabel {

    @IBInspectable var topInset: CGFloat = 4.0
    @IBInspectable var leftInset: CGFloat = 4.0
    @IBInspectable var bottomInset: CGFloat = 4.0
    @IBInspectable var rightInset: CGFloat = 4.0

    var insets: UIEdgeInsets {
        get {
            return UIEdgeInsets.init(top: topInset, left: leftInset, bottom: bottomInset, right: rightInset)
        }
        set {
            topInset = newValue.top
            leftInset = newValue.left
            bottomInset = newValue.bottom
            rightInset = newValue.right
        }
    }

    override func sizeThatFits(_ size: CGSize) -> CGSize {
        var adjSize = super.sizeThatFits(size)
        adjSize.width += leftInset + rightInset
        adjSize.height += topInset + bottomInset
        return adjSize
    }

    override var intrinsicContentSize: CGSize {
        let systemContentSize = super.intrinsicContentSize
        let adjustSize = CGSize(width: systemContentSize.width + leftInset + rightInset, height: systemContentSize.height + topInset +     bottomInset)
        if adjustSize.width > preferredMaxLayoutWidth && preferredMaxLayoutWidth != 0 {
            let constraintSize = CGSize(width: bounds.width - (leftInset + rightInset), height: .greatestFiniteMagnitude)
            let newSize = super.sizeThatFits(constraintSize)
            return CGSize(width: systemContentSize.width, height: ceil(newSize.height) + topInset + bottomInset)
        } else {
            return adjustSize
        }
    }

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

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

简单填充(Swift 3.0, Alvin George回答):

  class NewLabel: UILabel {

        override func textRect(forBounds bounds: CGRect, limitedToNumberOfLines numberOfLines: Int) -> CGRect {
                return self.bounds.insetBy(dx: CGFloat(15.0), dy: CGFloat(15.0))
        }

        override func draw(_ rect: CGRect) {
                super.drawText(in: self.bounds.insetBy(dx: CGFloat(5.0), dy: CGFloat(5.0)))
        }

  }

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:

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。