Unexpected behaviour when inserting new cells.

[markst]

I have my UICollectionView backed by a NSFetchedResultsController to insert/update cells.

My cells get inserted as the user scrolls. What seems to happen is the sticky headers scroll down & then return once the bounce deceleration animation is complete.

I think a solution would be to only insert cells once animation deceleration is complete.

[jamztang]

Can you provide more information or a sample project so we can take a look?

[markst]

http://d.pr/v/10Icq

[jamztang]

Which version are you using and is the bouncing the section header or the stickyheader?

[markst]

Using version 0.2.3

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView
           viewForSupplementaryElementOfKind:(NSString *)kind
                                 atIndexPath:(NSIndexPath *)indexPath
{
    if ([kind isEqualToString:CSStickyHeaderParallaxHeader]) {
        if (self.mapHeader == nil) {
            _mapHeader = [collectionView
                          dequeueReusableSupplementaryViewOfKind:CSStickyHeaderParallaxHeader
                          withReuseIdentifier:@"MapHeader"
                          forIndexPath:indexPath];

        }
        return self.mapHeader;
    } else if ([kind isEqualToString:UICollectionElementKindSectionHeader]) {

        //TODO: Move this to an appearance class.
        [[UITextField appearanceWhenContainedIn:[UISearchBar class], nil] setFont:[UIFont proximaNovaRegularFontWithSize:15.0]];

        UICollectionReusableView * cell = [collectionView
                                           dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader
                                           withReuseIdentifier:@"SearchHeader"
                                           forIndexPath:indexPath];
        UISearchBar * searchBar = (UISearchBar *)[cell viewWithTag:200];
        [searchBar setDelegate:self];
        [searchBar setPlaceholder:@"Search by Postcode or Suburb"];
        [searchBar setTintColor:[UIColor tn_charcoal]];
        [searchBar setBarTintColor:[UIColor whiteColor]];
        [searchBar setBackgroundColor:[UIColor whiteColor]];
        [searchBar setBackgroundImage:[UIImage new]];
        [searchBar setShowsCancelButton:YES];
        [searchBar setScopeBarButtonTitleTextAttributes:@{NSFontAttributeName:[UIFont proximaNovaBoldFontWithSize:15.0]}
                                               forState:UIControlStateNormal];
        return cell;
    }
    return nil;
}

[gjeck]

I have a similar issue on the same version. The stickyHeader and regular sectionHeader animate oddly when reloading sections. It seems that the stickyheader content is being animated when we expect it to remain static.

let indexSet = NSIndexSet(indexesInRange: NSMakeRange(0, self.collectionView.numberOfSections()))
collectionView.reloadSections(indexSet)

[jamztang]

I notice the initial attributes were not modified to reflect the change. I made a small patch and pushed to the demo project, let me know if that works for you guys!

[nferruzzi]

Same problem here and the small patch doesn't fix it for me. On my side the problem is triggered when I perform insertItemsAtIndexPath inside a performBatchUpdates; with a simple reloadData the sticky header works just fine.

[nbwar]

@nferruzzi Place your performBatchUpdates in a UIView.animationWithDuration block for example

UIView.animateWithDuration(0, animations: {
    self.collectionView.performBatchUpdates({
        var indexPaths:[NSIndexPath] = []

         for var i = oldSize; i < self.data.count; i++ {
            indexPaths.append(NSIndexPath(forItem: i, inSection: 0))
          }
          self.collectionView.insertItemsAtIndexPaths(indexPaths)
      }, completion: nil)
})

[jamztang]

0.2.8 has some updates on better handing animation, please feel free to reopen if still have issues.