+ (UIImage *)resizableImageWithName:(NSString *)imageName
{
// 加载原有图片
UIImage *norImage = [UIImage imageNamed:imageName];
// 获取原有图片的宽高的一半
CGFloat w = norImage.size.width * 0.5;
CGFloat h = norImage.size.height * 0.5;
// 生成可以拉伸指定位置的图片
UIImage *newImage = [norImage resizableImageWithCapInsets:UIEdgeInsetsMake(15, 10, h, w) resizingMode:UIImageResizingModeStretch];
return newImage;
}