#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];

}

返回一张自由拉伸的图片