如果是单行，只需在左侧添加空格，超过一行的填充将再次为0。

[self.myLabel setText:[NSString stringWithFormat:@"   %@", self.myShortString]];

为UILabel添加填充的最佳方法是子类化UILabel并添加一个edgeInsets属性。然后设置所需的插图，标签将相应地绘制。

OSLabel.h

#import <UIKit/UIKit.h>

@interface OSLabel : UILabel

@property (nonatomic, assign) UIEdgeInsets edgeInsets;

@end

OSLabel.m

#import "OSLabel.h"

@implementation OSLabel

- (id)initWithFrame:(CGRect)frame{
    self = [super initWithFrame:frame];
    if (self) {
        self.edgeInsets = UIEdgeInsetsMake(0, 0, 0, 0);
    }
    return self;
}

- (void)drawTextInRect:(CGRect)rect {
    [super drawTextInRect:UIEdgeInsetsInsetRect(rect, self.edgeInsets)];
}

- (CGSize)intrinsicContentSize
{
    CGSize size = [super intrinsicContentSize];
    size.width  += self.edgeInsets.left + self.edgeInsets.right;
    size.height += self.edgeInsets.top + self.edgeInsets.bottom;
    return size;
}

@end

设置标签的textAlignment属性为NSTextAlignmentRight并增加它的宽度。

这是我找到的最简单的解决方法:

斯威夫特4

class CustomLabel: UILabel{
    override func drawText(in rect: CGRect) {
        super.drawText(in: rect.inset(by: UIEdgeInsets.init(top: 10, left: 10, bottom: 10, right: 10)))
    }
}

确保在代码和故事板中都将标签设置为CustomLabel类。

和@IBDesignable，使其与接口生成器一起工作

斯威夫特4

//
//  PaddedLabel.swift
//  TrainCentric
//
//  Created by Arsonik
//  https://stackoverflow.com/a/33244365/337934
//

import UIKit

@IBDesignable
class PaddedLabel: UILabel {

    @IBInspectable var inset:CGSize = CGSize(width: 0, height: 0)

    var padding: UIEdgeInsets {
        var hasText:Bool = false
        if let t = self.text?.count, t > 0 {
            hasText = true
        }
        else if let t = attributedText?.length, t > 0 {
            hasText = true
        }

        return hasText ? UIEdgeInsets(top: inset.height, left: inset.width, bottom: inset.height, right: inset.width) : UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
    }

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

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

    override func sizeThatFits(_ size: CGSize) -> CGSize {
        let superSizeThatFits = super.sizeThatFits(size)
        let p = padding
        let width = superSizeThatFits.width + p.left + p.right
        let heigth = superSizeThatFits.height + p.top + p.bottom
        return CGSize(width: width, height: heigth)
    }
}

斯威夫特2

@IBDesignable
class PaddedLabel: UILabel {

    @IBInspectable var inset:CGSize = CGSize(width: 0, height: 0)

    var padding: UIEdgeInsets {
        var hasText:Bool = false
        if let t = text?.length where t > 0 {
            hasText = true
        }
        else if let t = attributedText?.length where t > 0 {
            hasText = true
        }

        return hasText ? UIEdgeInsets(top: inset.height, left: inset.width, bottom: inset.height, right: inset.width) : UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
    }

    override func drawTextInRect(rect: CGRect) {
        super.drawTextInRect(UIEdgeInsetsInsetRect(rect, padding))
    }

    override func intrinsicContentSize() -> CGSize {
        let superContentSize = super.intrinsicContentSize()
        let p = padding
        let width = superContentSize.width + p.left + p.right
        let heigth = superContentSize.height + p.top + p.bottom
        return CGSize(width: width, height: heigth)
    }

    override func sizeThatFits(size: CGSize) -> CGSize {
        let superSizeThatFits = super.sizeThatFits(size)
        let p = padding
        let width = superSizeThatFits.width + p.left + p.right
        let heigth = superSizeThatFits.height + p.top + p.bottom
        return CGSize(width: width, height: heigth)
    }
}

在Swift 3中，你可以通过创建UILabel的子类来达到你想要的效果。在这个子类中，你必须添加一个UIEdgeInsets属性，并覆盖drawText(In:)方法，intrinsicContentSize属性(用于自动布局代码)和/或sizeThatFits(_:)方法(用于Springs和Struts代码)。

import UIKit

class PaddingLabel: UILabel {

    let padding: UIEdgeInsets

    // Create a new PaddingLabel instance programamtically with the desired insets
    required init(padding: UIEdgeInsets = UIEdgeInsets(top: 0, left: 10, bottom: 0, right: 10)) {
        self.padding = padding
        super.init(frame: CGRect.zero)
    }

    // Create a new PaddingLabel instance programamtically with default insets
    override init(frame: CGRect) {
        padding = UIEdgeInsets.zero // set desired insets value according to your needs
        super.init(frame: frame)
    }

    // Create a new PaddingLabel instance from Storyboard with default insets
    required init?(coder aDecoder: NSCoder) {
        padding = UIEdgeInsets.zero // set desired insets value according to your needs
        super.init(coder: aDecoder)
    }

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

    // Override `intrinsicContentSize` property for Auto layout code
    override var intrinsicContentSize: CGSize {
        let superContentSize = super.intrinsicContentSize
        let width = superContentSize.width + padding.left + padding.right
        let height = superContentSize.height + padding.top + padding.bottom
        return CGSize(width: width, height: height)
    }

    // Override `sizeThatFits(_:)` method for Springs & Struts code
    override func sizeThatFits(_ size: CGSize) -> CGSize {
        let superSizeThatFits = super.sizeThatFits(size)
        let width = superSizeThatFits.width + padding.left + padding.right
        let heigth = superSizeThatFits.height + padding.top + padding.bottom
        return CGSize(width: width, height: heigth)
    }

}

下面的例子展示了如何在UIViewController中使用PaddingLabel实例:

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var storyboardAutoLayoutLabel: PaddingLabel!
    let autoLayoutLabel = PaddingLabel(padding: UIEdgeInsets(top: 20, left: 40, bottom: 20, right: 40))
    let springsAndStructsLabel = PaddingLabel(frame: CGRect.zero)
    var textToDisplay = "Lorem ipsum dolor sit er elit lamet."

    override func viewDidLoad() {
        super.viewDidLoad()

        // Set autoLayoutLabel
        autoLayoutLabel.text = textToDisplay
        autoLayoutLabel.backgroundColor = .red
        autoLayoutLabel.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(autoLayoutLabel)
        autoLayoutLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 30).isActive = true
        autoLayoutLabel.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true

        // Set springsAndStructsLabel
        springsAndStructsLabel.text = textToDisplay
        springsAndStructsLabel.backgroundColor = .green
        view.addSubview(springsAndStructsLabel)
        springsAndStructsLabel.frame.origin = CGPoint(x: 30, y: 90)
        springsAndStructsLabel.sizeToFit()

        // Set storyboardAutoLayoutLabel
        storyboardAutoLayoutLabel.text = textToDisplay
        storyboardAutoLayoutLabel.backgroundColor = .blue
    }

    // Link this IBAction to a UIButton or a UIBarButtonItem in Storyboard
    @IBAction func updateLabelText(_ sender: Any) {
        textToDisplay = textToDisplay == "Lorem ipsum dolor sit er elit lamet." ? "Lorem ipsum." : "Lorem ipsum dolor sit er elit lamet."

        // autoLayoutLabel
        autoLayoutLabel.text = textToDisplay

        // springsAndStructsLabel
        springsAndStructsLabel.text = textToDisplay
        springsAndStructsLabel.sizeToFit()

        // storyboardAutoLayoutLabel
        storyboardAutoLayoutLabel.text = textToDisplay
    }

}