How to update UIPageControl when UIScrollView with PagingEnabled changes page?

Question

How do i make it so that when the user scrolls to a new page in UIScrollView, the UIPageControl updates?

Answer 1

I have used this before and it seemed to work well. Be sure to set the UIScrollView.delegate to self.

#pragma mark - UIScrollViewDelegate methods

- (void)scrollViewDidEndDecelerating:(UIScrollView *)sender {
    uint page = sender.contentOffset.x / width;
    [self.pageControl setCurrentPage:page];
}

Answer 2

Where you defined your UIScrollView and UIPageControl, you have to implement this method :

- (void)scrollViewDidScroll:(UIScrollView *)_scrollView
{
    if (pageControlIsChangingPage)
        return;

    CGFloat pageWidth = _scrollView.frame.size.width;
    int page = floor((_scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
    pageControl.currentPage = page;
}

and this one :

- (void)scrollViewDidEndDecelerating:(UIScrollView *)_scrollView 
{
    pageControlIsChangingPage = NO;
}

where pageControlIsChangingPage is :

BOOL    pageControlIsChangingPage;

Answer 3

Here is an update of this answer for Swift as well:

func scrollViewDidEndDecelerating(scrollView: UIScrollView) {
            pageControl.currentPage = Int(myScrollView.contentOffset.x) / Int(myScrollView.frame.width)
        }