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
        }
    }
}

简单的方法

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        self.view.addSubview(makeLabel("my title",x: 0, y: 100, w: 320, h: 30))
    }

    func makeLabel(title:String, x:CGFloat, y:CGFloat, w:CGFloat, h:CGFloat)->UILabel{
        var myLabel : UILabel = UILabel(frame: CGRectMake(x,y,w,h))
        myLabel.textAlignment = NSTextAlignment.Right

        // inser last char to right
        var titlePlus1char = "\(title)1"
        myLabel.text = titlePlus1char
        var titleSize:Int = count(titlePlus1char)-1

        myLabel.textColor = UIColor(red:1.0, green:1.0,blue:1.0,alpha:1.0)
        myLabel.backgroundColor = UIColor(red: 214/255, green: 167/255, blue: 0/255,alpha:1.0)


        // create myMutable String
        var myMutableString = NSMutableAttributedString()

        // create myMutable font
        myMutableString = NSMutableAttributedString(string: titlePlus1char, attributes: [NSFontAttributeName:UIFont(name: "HelveticaNeue", size: 20)!])

        // set margin size
        myMutableString.addAttribute(NSFontAttributeName, value: UIFont(name: "HelveticaNeue", size: 10)!, range: NSRange(location: titleSize,length: 1))

        // set last char to alpha 0
        myMutableString.addAttribute(NSForegroundColorAttributeName, value: UIColor(red:1.0, green:1.0,blue:1.0,alpha:0), range: NSRange(location: titleSize,length: 1))

        myLabel.attributedText = myMutableString

        return myLabel
    }


    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

}

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

只需使用一个UIView作为一个superview，并定义一个固定的边距标签与自动布局。

在Swift 3中

最好最简单的方法

class UILabelPadded: UILabel {
     override func drawText(in rect: CGRect) {
     let insets = UIEdgeInsets.init(top: 0, left: 5, bottom: 0, right: 5)
     super.drawText(in: UIEdgeInsetsInsetRect(rect, insets))
    }

}

如果你想在textRect周围添加2px的填充，只需要这样做:

let insets = UIEdgeInsets(top: -2, left: -2, bottom: -2, right: -2)
label.frame = UIEdgeInsetsInsetRect(textRect, insets)