《转》http://www.cnblogs.com/Phelthas/p/4452235.html
写一个UIButton的category

使用方法：掉.h文件的唯一方法，传入你想要的图片位置枚举类型如：WZ_ImagePositionTop，即可。
若有需要，传入文字和图片之间的间距spacing

=============.h文件=========
#import <UIKit/UIKit.h>

  typedef NS_ENUM(NSInteger, WZ_ImagePosition) {
WZ_ImagePositionLeft = 0,              //图片在左，文字在右，默认
WZ_ImagePositionRight = 1,             //图片在右，文字在左
WZ_ImagePositionTop = 2,               //图片在上，文字在下
WZ_ImagePositionBottom = 3,            //图片在下，文字在上
  };

  @interface UIButton (WZ_ImagePosition)

  /**
   *  利用UIButton的titleEdgeInsets和imageEdgeInsets来实现文字和图片的自由排列
   *  注意：这个方法需要在设置图片和文字之后才可以调用，且button的大小要大于 图片大小+文字大小+spacing
   *
   *  @param spacing 图片和文字的间隔
   */
  - (void)setImagePosition:(WZ_ImagePosition)postion spacing:(CGFloat)spacing;

=============.m文件=========

 #import "UIButton+WZButtonImagePosition.h"

 @implementation UIButton (WZButtonImagePosition)
- (void)setImagePosition:(WZ_ImagePosition)postion spacing:(CGFloat)spacing {
[self setTitle:self.currentTitle forState:UIControlStateNormal];
[self setImage:self.currentImage forState:UIControlStateNormal];


CGFloat imageWidth = self.imageView.image.size.width;
CGFloat imageHeight = self.imageView.image.size.height;
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-    Wdeprecated-declarations"
CGFloat labelWidth = [self.titleLabel.text sizeWithFont:self.titleLabel.font].width;
CGFloat labelHeight = [self.titleLabel.text sizeWithFont:self.titleLabel.font].height;
#pragma clang diagnostic pop

CGFloat imageOffsetX = (imageWidth + labelWidth) / 2 - imageWidth / 2;//image中心移动的x距离
CGFloat imageOffsetY = imageHeight / 2 + spacing / 2;//image中心移动的y距离
CGFloat labelOffsetX = (imageWidth + labelWidth / 2) - (imageWidth + labelWidth) / 2;//label中心移动的x距离
CGFloat labelOffsetY = labelHeight / 2 + spacing / 2;//label中心移动的y距离

CGFloat tempWidth = MAX(labelWidth, imageWidth);
CGFloat changedWidth = labelWidth + imageWidth - tempWidth;
CGFloat tempHeight = MAX(labelHeight, imageHeight);
CGFloat changedHeight = labelHeight + imageHeight + spacing - tempHeight;

switch (postion) {
    case WZ_ImagePositionLeft:
        self.imageEdgeInsets = UIEdgeInsetsMake(0, -spacing/2, 0, spacing/2);
        self.titleEdgeInsets = UIEdgeInsetsMake(0, spacing/2, 0, -spacing/2);
        self.contentEdgeInsets = UIEdgeInsetsMake(0, spacing/2, 0, spacing/2);
        break;
        
    case WZ_ImagePositionRight:
        self.imageEdgeInsets = UIEdgeInsetsMake(0, labelWidth + spacing/2, 0, -(labelWidth + spacing/2));
        self.titleEdgeInsets = UIEdgeInsetsMake(0, -(imageWidth + spacing/2), 0, imageWidth + spacing/2);
        self.contentEdgeInsets = UIEdgeInsetsMake(0, spacing/2, 0, spacing/2);
        break;
        
    case WZ_ImagePositionTop:
        self.imageEdgeInsets = UIEdgeInsetsMake(-imageOffsetY, imageOffsetX, imageOffsetY, -imageOffsetX);
        self.titleEdgeInsets = UIEdgeInsetsMake(labelOffsetY, -labelOffsetX, -labelOffsetY, labelOffsetX);
        self.contentEdgeInsets = UIEdgeInsetsMake(imageOffsetY, -changedWidth/2, changedHeight-imageOffsetY, -changedWidth/2);
        break;
        
    case WZ_ImagePositionBottom:
        self.imageEdgeInsets = UIEdgeInsetsMake(imageOffsetY, imageOffsetX, -imageOffsetY, -imageOffsetX);
        self.titleEdgeInsets = UIEdgeInsetsMake(-labelOffsetY, -labelOffsetX, labelOffsetY, labelOffsetX);
        self.contentEdgeInsets = UIEdgeInsetsMake(changedHeight-imageOffsetY, -changedWidth/2, imageOffsetY, -changedWidth/2);
        break;
        
    default:
        break;
}

}
@end