导航栏右边按钮保持原来图片颜色

• (UIImage *)imageRendingMode:(NSString *)imageName
  {
  UIImage *image = [UIImage imageNamed:imageName];
  image = [image imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

  return image;
  }
  UIBarButtonItem *barButton = [[UIBarButtonItem alloc] initWithImage:[UIImage imageRendingMode:@"clothsearch"] style:UIBarButtonItemStylePlain target:self action:@selector(search)];