Question

在我的应用程序中使用4页的分页概念和UIScrollView。它的工作正常但是我的问题是的 1 我想在第1页结尾显示第2页（部分内容），第2页结束的第3页（部分）第3页结束时的第4页（部分）。

2 现在我可以再次从第1页移动到第2页，第2页到第3页，第3页再到第4页如果要移动到第1页意味着我必须去4-3-2-1这样的页面但是我想像1-2-3-4-1-2-3那样循环移动页面，就像那样

示例代码

    NSMutableArray *controllers = [[NSMutableArray alloc] init];
for (unsigned i = 0; i < kNumberOfPages; i++)
{
    [controllers addObject:[NSNull null]];
}
self.viewControllers = controllers;


// a page is the width of the scroll view
scrollView.pagingEnabled = YES;
scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * kNumberOfPages, 1);
scrollView.showsHorizontalScrollIndicator = NO;
scrollView.showsVerticalScrollIndicator = NO;
scrollView.scrollsToTop = NO;
scrollView.delegate = self;

pageControl.numberOfPages = kNumberOfPages;
pageControl.currentPage = 0;

// pages are created on demand
// load the visible page
// load the page on either side to avoid flashes when the user starts scrolling
[self loadScrollViewWithPage:0];
[self loadScrollViewWithPage:1];

}

- (void)loadScrollViewWithPage:(int)page {
if (page < 0) return;
if (page >= kNumberOfPages) return;

// replace the placeholder if necessary
WhatsNewViewConroller *controller = [viewControllers objectAtIndex:page];
if ((NSNull *)controller == [NSNull null]) {
    controller = [[WhatsNewViewConroller alloc] initWithPageNumber:page];
    [viewControllers replaceObjectAtIndex:page withObject:controller];
    controller.delegateController = self;
}

// add the controller's view to the scroll view
if (nil == controller.view.superview) {
    CGRect frame = scrollView.frame;
    frame.origin.x = frame.size.width * page;
    frame.origin.y = 0;
    controller.view.frame = frame;
    [scrollView addSubview:controller.view];
}

}

- (void)scrollViewDidScroll:(UIScrollView *)sender {
// We don't want a "feedback loop" between the UIPageControl and the scroll delegate in
// which a scroll event generated from the user hitting the page control triggers updates from
// the delegate method. We use a boolean to disable the delegate logic when the page control is used.
if (pageControlUsed) {
    // do nothing - the scroll was initiated from the page control, not the user dragging
    return;
}

// Switch the indicator when more than 50% of the previous/next page is visible
CGFloat pageWidth = scrollView.frame.size.width;
int page = floor((scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
pageControl.currentPage = page;

// load the visible page and the page on either side of it (to avoid flashes when the user starts scrolling)
[self loadScrollViewWithPage:page - 1];
[self loadScrollViewWithPage:page];
[self loadScrollViewWithPage:page + 1];

// A possible optimization would be to unload the views+controllers which are no longer visible

}

这里正在改变页面

- (IBAction)changePage:(id)sender {
int page = pageControl.currentPage;

// load the visible page and the page on either side of it (to avoid flashes when the user starts scrolling)
[self loadScrollViewWithPage:page - 1];
[self loadScrollViewWithPage:page];
[self loadScrollViewWithPage:page + 1];

// update the scroll view to the appropriate page
CGRect frame = scrollView.frame;
frame.origin.x = frame.size.width * page;
frame.origin.y = 0;
[scrollView scrollRectToVisible:frame animated:YES];

// Set the boolean used when scrolls originate from the UIPageControl. See scrollViewDidScroll: above.
pageControlUsed = YES;

}

任何人都可以提供帮助或建议。

提前致谢

Answer 1

当你加载新页面时，而不是使用page-1，page和page + 1;使用（第-1页）％4，第％4页和（第+ 1页）％4

关于分页和从一个页面循环移动到另一个页面

1 个答案: