Scroll child scrollview only when parent scroll view reaches end

Question

I have a parent UIScrollView and a UICollectionView inside that UIScrollView. I want that UICollectionView scroll begins only when the parent UIScrollView reaches end of its scrolling. Can any one please help me for the same.

put one codition in scrollview delagates method and check the your current scroll is end of your first scroll then disable it and make child scroll enable — Himanshu Moradiya, Jan 04 '17 at 10:35
you need off scrolling for collection view if Current contentOffSet of scrollview less than max off set of this scroll — Matloob Hasnain, Jan 04 '17 at 10:36
Can you please show what all you may have tried in solving your problem? — Rikh, Jan 04 '17 at 10:42

score 1 · Answer 1 · answered Jan 04 '17 at 10:44

In viewDidLoad, Disable Collectionview scroll.

self.collectionView.scrollEnabled = NO;

Now, Use Delegate of scrollview to detect bottom of the scroll view and than enable CollectionView scroll.

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
    float bottomEdge = scrollView.contentOffset.y + scrollView.frame.size.height;
    if (bottomEdge >= scrollView.contentSize.height) {
       self.collectionView.scrollEnabled = YES;
    }
}

Hope it will work.

score 0 · Answer 2 · edited May 23 '17 at 10:30

Initially set the child scrollView yourScrollView.scrollEnabled = NO; also add tags to your scrollViews. 1 for parent and 2 for child preferably.

Get to know if you are at the bottom of the ScrollView using this code

-(void)scrollViewDidScroll: (UIScrollView*)scrollView
{
    if(scrollView.tag==1)
    {
    float scrollViewHeight = scrollView.frame.size.height;
    float scrollContentSizeHeight = scrollView.contentSize.height;
    float scrollOffset = scrollView.contentOffset.y;

    if (scrollOffset == 0)
    {
        // then we are at the top
    }
    else if (scrollOffset + scrollViewHeight == scrollContentSizeHeight)
    {
        //Handle Code to activate the child scrollView.
        // then we are at the end
    }
    }
}

Hope this helps. Happy Coding.

References SO Post

Scroll child scrollview only when parent scroll view reaches end

2 Answers2