Make UIScrollView wrap around

Question

Possible Duplicate:
UIScrollView. Any thoughts on implementing “infinite” scroll/zoom?

I have a UIScroll which has eight or so pages. My aim is for them to 'loop' around so that when the user reaches the last page the first page will be the next page (and vice versa) so that the user could scroll through the pages endlessly. What is the best way to achieve this?

I am working from this example from Cocoa with Love.

Any help is greatly appreciated. Thank you.

Duplicate? [here](http://stackoverflow.com/questions/1383849/loop-an-uiscrollview) or [here](http://stackoverflow.com/questions/1795086/is-there-an-easy-way-to-make-a-horizontally-paged-uiscrollview-wrap-around) and [here](http://stackoverflow.com/questions/1493950/uiscrollview-any-thoughts-on-implementing-infinite-scroll-zoom/1494022#1494022) — progrmr, Jun 18 '10 at 17:20

score 21 · Accepted Answer · edited Nov 10 '11 at 20:53

21

Problem is sorted now. Basically, I created extra pages before and after my pages so it looks like this:

8 1 2 3 4 5 6 7 8 1

Then in the scrollViewDidEndDecelerating I do a simple if statement that checks if I am at either the first or last page and locate the scrollView appropriately.

- (void)scrollViewDidEndDecelerating:(UIScrollView *)newScrollView
{
    [self scrollViewDidEndScrollingAnimation:newScrollView];
    pageControl.currentPage = currentPage.pageIndex;

    if(currentPage.pageIndex==0){
        scrollView.contentOffset = CGPointMake(320*(pageControl.numberOfPages-2), 0);
        pageControl.currentPage = pageControl.numberOfPages-2;
    }else if(currentPage.pageIndex==pageControl.numberOfPages-1){
        scrollView.contentOffset = CGPointMake(320, 0);
        pageControl.currentPage = 1;
    }

}

edited Nov 10 '11 at 20:53

pablasso

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answered Jun 19 '10 at 12:42

Andrew Davis

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Hi Andrew! I try that, and it woks fine. What about if want to show 3 images at the time and have the same effect?? Can you help me?? – Frade Dec 14 '11 at 11:39
I needed to this for a project as well so for reference I started with the PageControl sample from http://developer.apple.com/library/ios/#samplecode/PageControl/Introduction/Intro.html#//apple_ref/doc/uid/DTS40007795 and modified it with Andrew Davis's technique to include looped scrolling. The modified example is here https://github.com/j1mr10rd4n/LoopyPageControl in case it's useful to anyone. – Jim Riordan Nov 03 '12 at 22:18

score 3 · Answer 2 · answered Mar 01 '12 at 17:27

For anyone else trying to solve this problem, I would recommend taking a look at apple's video, which includes a tutorial for infinite scrolling & wrapping: https://developer.apple.com/videos/wwdc/2011/

Along with its sample code: https://developer.apple.com/library/ios/#samplecode/StreetScroller/Introduction/Intro.html

I'm currently using the "8 1 2 3 4 5 6 7 8 1" method and haven't attempted to implement the method described in the video yet, but it appears that it could prevent the small "bounce" at the last or first page you can encounter when scrolling quickly on the 8 1 2...1 method.

Make UIScrollView wrap around

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