iOS UIButton运用EdgeInsets实现上图下文

 设置button的字体大小为12：button.titleLabel.font = [UIFont systemFontOfSize:12];

-(void)setEdgeInsets:(UIButton *)button andImage:(UIImage *)image andTitle:(NSString *)titleStr

{
    CGSize size = [titleStr boundingRectWithSize:CGSizeMake(MAXFLOAT, button.titleLabel.frame.size.height) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:12]} context:nil].size;
    
    button.titleEdgeInsets = UIEdgeInsetsMake(0.5 * image.size.height, -0.5 * image.size.width, -0.5 * image.size.height, 0.5 * image.size.width);
    button.imageEdgeInsets = UIEdgeInsetsMake(-0.5 * size.height, 0.5 * size.width, 0.5 * size.height, -0.5 * size.width);
}