要扩展Brody Robertson提供的答案，您可以添加IB可设计位。这意味着您可以在Storyboard中调整标签。

在你的子类UILabel做

#import <UIKit/UIKit.h>

IB_DESIGNABLE

@interface insetLabel : UILabel

@property (nonatomic, assign) IBInspectable CGFloat leftEdge;
@property (nonatomic, assign) IBInspectable CGFloat rightEdge;
@property (nonatomic, assign) IBInspectable CGFloat topEdge;
@property (nonatomic, assign) IBInspectable CGFloat bottomEdge;

@property (nonatomic, assign) UIEdgeInsets edgeInsets;

@end

然后做;

#import "insetLabel.h"

@implementation insetLabel

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

- (void)drawTextInRect:(CGRect)rect
{
    self.edgeInsets = UIEdgeInsetsMake(self.topEdge, self.leftEdge, self.bottomEdge, self.rightEdge);

    [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

EDIT

你应该为edgeInsets添加一个setter方法。

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

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
    }
}

我认为UILabel类没有设置边距的方法。为什么不把标签的位置设置在需要的位置?

见下面的代码:

UILabel *label = [[UILabel alloc] init];
label.text = @"This is label";
label.frame = CGRectMake(0,0,100,100);

如果来自接口构建器，则按以下方式定位Label:

yourLabel.frame = CGRectMake(0,0,100,100);

对于Xamarin用户(使用统一API):

class UIMarginLabel : UILabel
{
    public UIMarginLabel()
    {
    }

    public UIMarginLabel( CGRect frame ) : base( frame )
    {
    }

    public UIEdgeInsets Insets { get; set; }

    public override void DrawText( CGRect rect )
    {
        base.DrawText( Insets.InsetRect( rect ) );
    }
}

对于那些使用原始MonoTouch API的人:

public class UIMarginLabel : UILabel
{
    public UIEdgeInsets Insets { get; set; }

    public UIMarginLabel() : base()
    {
        Insets = new UIEdgeInsets(0, 0, 0, 0);
    }
    public UIMarginLabel(RectangleF frame) : base(frame)
    {
        Insets = new UIEdgeInsets(0, 0, 0, 0);
    }

    public override void DrawText(RectangleF frame)
    {
        base.DrawText(new RectangleF(
            frame.X + Insets.Left,
            frame.Y + Insets.Top,
            frame.Width - Insets.Left - Insets.Right,
            frame.Height - Insets.Top - Insets.Bottom));
    }
}

在Swift中，它是这样解决的。

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