uiscrollview 删除子view时，继续滚动到被删除的索引。

问题：我在做一个相册的时候，如果删除uiscrollerview的元素，假如原本scroll的元素为9，然后我 删除1个，元素，接着把9个元素都删除掉，再重新添加8个元素，结果scroller在滚动时也可以滚动到第9个位置上。这是如果删除第9个元素，会报错，解决办法是动态的设置uisrollerview的contentSize。这样就可以了。

例子代码如下

//更新相片
-(void)UpdatePhoto
{
      NSLog(@"imageNameCount:%d---scrollIndex:%d",self.imageNameArray.count,scrollIndex);
    for(int i = 0;i<self.imageNameArray.count;i++)
    {
        UIView *bgView = [[UIView alloc]initWithFrame:CGRectMake(1024*i, 0, 1024, 700)];
        bgView.backgroundColor = [UIColor blackColor];
        
        UIImageView *photoView = [[UIImageView alloc]init];
        photoView.image = [self.bigImageArray objectAtIndex:i];
        photoView.frame = CGRectMake(0, 0, photoView.image.size.width, photoView.image.size.height);
        photoView.center = CGPointMake(512, 359);
        
        [bgView addSubview:photoView];
        [photoScrollView addSubview:bgView];
    }
     //添加这一句就行了。
    self.photoScrollView.contentSize = CGSizeMake(1024*self.imageNameArray.count, 700);

    CGRect  Positionframe = CGRectMake(1024*scrollIndex, 0, 1024, 700);
    [self.photoScrollView scrollRectToVisible:Positionframe animated:NO];
}