How to detect scrolling to a new section in a UICollectionView?

I am implementing an infinite-scrolling calendar. My issue is that I would like to set the current month as the title in the navigation bar and it should update while scrolling - once you pass the section header view the title should update in the nav bar.

A possible solution would be to set the view title in the method called - (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath so that, when I calculate a new section Header, it also updates the title. The problem with this is that the title changes when the new section is at the bottom of the page.

Is there a way to know the "current section" of UICollectionView once the user has scrolled to it? Or can you think of a way to improve my current solution?

To help the readers of this post, I posted my own sample code for this question at this GitHub repo.

change below line in method viewForSupplementaryElementOfKind :

self.title = [df stringFromDate:[self dateForFirstDayInSection:indexPath.section]];

to this:

    if(![[self dateForFirstDayInSection:indexPath.section-1] isKindOfClass:[NSNull class]]){
        self.title = [df stringFromDate:[self dateForFirstDayInSection:indexPath.section-1]];
}

Hope it will help you.