#pragma mark- 返回一张自由拉伸的图片
+ (UIImage *)resizableImage:(NSString *)name
{
UIImage *image = [self imageWithName:name];
CGFloat left = image.size.width * 0.5;
CGFloat top = image.size.height * 0.5;
return [image stretchableImageWithLeftCapWidth:left topCapHeight:top];
}