在我的应用程序中，我使用 4 页的分页概念和 UIScrollView。它工作正常，但我的问题是 1。 我想在第 1 页结尾显示第 2 页（某些部分），在第 2 页结尾显示第 3 页（某些部分），在第 3 页结尾显示第 4 页（某些部分）。
2. 现在我可以再次从第 1 页移动到第 2 页，第 2 到第 3 页，第 3 到第 4 页，如果想移动到第 1 页意味着我必须像 4-3-2-1 这样的页面，但我想像 1 一样循环移动页面-2-3-4-1-2-3-.....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
}
这里正在更改页面
- (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