UIScrollView 中的向后滚动

Question

您好，我正在使用 uiscrollview 实现应用程序。在 uiscroll 视图中，我有 imageview 来加载图像。我可以像 1,2,3,4,...10 一样滚动和向前移动，但是当我在第一个图像中时，我想向后滚动也像 1 到 10,9,8... 可以任何人都可以帮助我在我的代码中添加什么，谢谢

这是我实现的示例代码

- (void)loadScrollViewWithPage:(int)page {

  if(page < 0 ||  (page >= [flashCardArry count]))
      return;
    FlashcardViewController *flashViewCntlObj = [flashCardViewController objectAtIndex:page%3];
  //if (nil == flashViewCntlObj.view.superview)
  {

    CGRect frame = cardsScrollView.frame;
    frame.origin.x = frame.size.width * page;


    NSLog(@"%f",frame.origin.x);
    frame.origin.y = 0;
    flashViewCntlObj.view.frame = frame;
    [cardsScrollView addSubview:flashViewCntlObj.view];

    [flashViewCntlObj setflashcardObj:[flashCardArry objectAtIndex:page]];
  }

}


- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
    //iscardAttended = NO;

    CGFloat pageWidth = cardsScrollView.frame.size.width;
    NSUInteger page = floor((self.cardsScrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
    if(page + 1 == [flashCardArry count]){
        for (NSUInteger i = 0; i < [flashCardArry count]; ++i) {
            int nElements = [flashCardArry count] - i;
            int n = (arc4random() % nElements) + i;
            [flashCardArry exchangeObjectAtIndex:i withObjectAtIndex:n];
        }
        [self.cardsScrollView scrollRectToVisible:CGRectMake(self.cardsScrollView.frame.size.width * 0 , 0, self.cardsScrollView.frame.size.width, self.cardsScrollView.frame.size.height)  animated:NO];
    }
}


-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{

  CGFloat pageWidth = cardsScrollView.frame.size.width;

  NSUInteger page = floor((self.cardsScrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;

      DBWrapper *dbWrapper = [DBWrapper sharedWrapper];

    [self loadScrollViewWithPage:page - 1];
     [self loadScrollViewWithPage:page];
     [self loadScrollViewWithPage:page + 1];
}

Answer 1

观看 WWDC 2011 中的 高级 ScrollView 技术 https://developer.apple.com/videos/wwdc/2011/