1. 设置button.titleLabel的文字居左或居右显示：

// button.titleLabel.textAlignment = NSTextAlignmentLeft; 这句无效  
button.contentHorizontalAlignment = UIControlContentHorizontalAlignmentLeft;  // 设置居左
button.titleEdgeInsets = UIEdgeInsetsMake(0, 10, 0, 0);  // 设置内边距（否则紧贴边框）

2. 修改button热区（响应范围）

在UIButton的category.m文件中修改实例方法的实现

// 若原热区小于44x44，则放大热区，否则保持原大小不变
- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event
{
    CGRect bounds = self.bounds;
    
    CGFloat widthDelta = MAX(44.0 - bounds.size.width, 0);
    CGFloat heightDelta = MAX(44.0 - bounds.size.height, 0);
    bounds = CGRectInset(bounds, -0.5 * widthDelta, -0.5 * heightDelta);
    return CGRectContainsPoint(bounds, point);
}

3. 设置button的titleLabel和imageView的布局样式，及间距

在UIButton的Category中添加以下枚举和方法

#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 (Category)

/**
 *  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

#import "UIButton+Category.h"

@implementation UIButton (Category)

- (void)layoutButtonWithEdgeInsetsStyle:(MKButtonEdgeInsetsStyle)style
                        imageTitleSpace:(CGFloat)space
{
    // 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;
    labelWidth = self.titleLabel.intrinsicContentSize.width;
    labelHeight = self.titleLabel.intrinsicContentSize.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