• 在设置这两个之前，我们先要理解Button上面的titleLabel和imageView的位置关系（想象Button默认的image和label的显示）：

我们知道，默认情况下如果UIbutton同时设置了标题和图片的情况下，titleLabel在image的右侧。

1.titleEdgeInsets是titleLabel相对于其上下左右的inset，跟tableView的contentInset是类似的；

2.如果只有title，那titleLabel的 上下左右 都是 相对于Button 的；

3.如果只有image，那imageView的 上下左右 都是 相对于Button 的；

4.如果同时有image和label，那image的 上下左 是 相对于Button 的，右 是 相对于label 的；
label的 上下右 是 相对于Button的， 左 是 相对于label 的。

0x01.新建一个UIButton类。

xx.h

#import <UIKit/UIKit.h>

typedef NS_ENUM(NSUInteger, MKButtonEdgeInsetsStyle) {
    MKButtonEdgeInsetsStyleTop, // image在上，label在下
    MKButtonEdgeInsetsStyleLeft, // image在左，label在右
    MKButtonEdgeInsetsStyleBottom, // image在下，label在上
    MKButtonEdgeInsetsStyleRight // image在右，label在左
};

@interface UIButton (ImageTitleSpacing)

/**
 *  设置button的titleLabel和imageView的布局样式，及间距
 *
 *  @param style titleLabel和imageView的布局样式
 *  @param space titleLabel和imageView的间距
 */
- (void)layoutButtonWithEdgeInsetsStyle:(MKButtonEdgeInsetsStyle)style
                        imageTitleSpace:(CGFloat)space;

@end

xx.m

#import "UIButton+ImageTitleSpacing.h"

@implementation UIButton (ImageTitleSpacing)

- (void)layoutButtonWithEdgeInsetsStyle:(MKButtonEdgeInsetsStyle)style
                        imageTitleSpace:(CGFloat)space
{
//    self.backgroundColor = [UIColor cyanColor];
    
    /**
     *  前置知识点：titleEdgeInsets是title相对于其上下左右的inset，跟tableView的contentInset是类似的，
     *  如果只有title，那它上下左右都是相对于button的，image也是一样；
     *  如果同时有image和label，那这时候image的上左下是相对于button，右边是相对于label的；title的上右下是相对于button，左边是相对于image的。
     */

    
    // 1. 得到imageView和titleLabel的宽、高
    CGFloat imageWith = self.imageView.frame.size.width;
    CGFloat imageHeight = self.imageView.frame.size.height;
    
    CGFloat labelWidth = 0.0;
    CGFloat labelHeight = 0.0;
    if ([UIDevice currentDevice].systemVersion.floatValue >= 8.0) {
        // 由于iOS8中titleLabel的size为0，用下面的这种设置
        labelWidth = self.titleLabel.intrinsicContentSize.width;
        labelHeight = self.titleLabel.intrinsicContentSize.height;
    } else {
        labelWidth = self.titleLabel.frame.size.width;
        labelHeight = self.titleLabel.frame.size.height;
    }
    
    // 2. 声明全局的imageEdgeInsets和labelEdgeInsets
    UIEdgeInsets imageEdgeInsets = UIEdgeInsetsZero;
    UIEdgeInsets labelEdgeInsets = UIEdgeInsetsZero;
    
    // 3. 根据style和space得到imageEdgeInsets和labelEdgeInsets的值
    switch (style) {
        case MKButtonEdgeInsetsStyleTop:
        {
            imageEdgeInsets = UIEdgeInsetsMake(-labelHeight-space/2.0, 0, 0, -labelWidth);
            labelEdgeInsets = UIEdgeInsetsMake(0, -imageWith, -imageHeight-space/2.0, 0);
        }
            break;
        case MKButtonEdgeInsetsStyleLeft:
        {
            imageEdgeInsets = UIEdgeInsetsMake(0, -space/2.0, 0, space/2.0);
            labelEdgeInsets = UIEdgeInsetsMake(0, space/2.0, 0, -space/2.0);
        }
            break;
        case MKButtonEdgeInsetsStyleBottom:
        {
            imageEdgeInsets = UIEdgeInsetsMake(0, 0, -labelHeight-space/2.0, -labelWidth);
            labelEdgeInsets = UIEdgeInsetsMake(-imageHeight-space/2.0, -imageWith, 0, 0);
        }
            break;
        case MKButtonEdgeInsetsStyleRight:
        {
            imageEdgeInsets = UIEdgeInsetsMake(0, labelWidth+space/2.0, 0, -labelWidth-space/2.0);
            labelEdgeInsets = UIEdgeInsetsMake(0, -imageWith-space/2.0, 0, imageWith+space/2.0);
        }
            break;
        default:
            break;
    }
    
    // 4. 赋值
    self.titleEdgeInsets = labelEdgeInsets;
    self.imageEdgeInsets = imageEdgeInsets;
}

@end

0x02.使用方法。

#import "ViewController.h"
#import "xx.h"

@interface ViewController ()

@property (weak, nonatomic) IBOutlet UIButton *topButton;
@property (weak, nonatomic) IBOutlet UIButton *leftButton;
@property (weak, nonatomic) IBOutlet UIButton *bottomButton;
@property (weak, nonatomic) IBOutlet UIButton *rightButton;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    [self updateUI];
}

- (void)updateUI {
    CGFloat space = 20.0;
    [self.topButton layoutButtonWithEdgeInsetsStyle:MKButtonEdgeInsetsStyleTop
                                    imageTitleSpace:space];
    
    [self.leftButton layoutButtonWithEdgeInsetsStyle:MKButtonEdgeInsetsStyleLeft
                                     imageTitleSpace:space];
    
    [self.bottomButton layoutButtonWithEdgeInsetsStyle:MKButtonEdgeInsetsStyleBottom
                                       imageTitleSpace:space];
    
    [self.rightButton layoutButtonWithEdgeInsetsStyle:MKButtonEdgeInsetsStyleRight
                                      imageTitleSpace:space];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end