Removing empty space, if the section header is hidden in the UICollectionView

Question

I have two sections in UICollectionView. I want to show a section header in UICollectionView for only 1st section. Not in 0th section.

So I tried to return nil in viewForSupplementaryElementOfKind: method for section == 0 and returns view for the section == 1.

It crashes and shows below error:

Assertion failure in -[UICollectionView _createPreparedSupplementaryViewForElementOfKind:atIndexPath:withLayoutAttributes:applyAttributes]: 

Here it is my code for the supplementary view.

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath {     UICollectionReusableView *sectionHeader = nil;     if (kind == UICollectionElementKindSectionHeader && indexPath.section == 1) {         sectionHeader = [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:@"EventSectionHeader" forIndexPath:indexPath];         sectionHeader.layer.borderWidth = .5f;         sectionHeader.layer.borderColor = [UIColor colorWithRed:221.0 / 255.0 green:223.0 / 255.0 blue:220.0 / 255.0 alpha:1.0].CGColor;     }      return sectionHeader; } 

I have found that returning nil in viewForSupplementaryElementOfKind: method crashing for others too. Other answers suggesting to remove that method.

But I want to show section header for specific sections only. How to achieve that returning view for only one section? Thanks. Any help would be appreciated.

EDIT:

As @san said, I have updated code to hide the section header. It works. It hides the header. But I am still seeing the empty space in the place of section header. Expected results is there should be no space for section header, if it is hidden.

updated code:

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath {      UICollectionReusableView *sectionHeader = nil;     if (kind == UICollectionElementKindSectionHeader) {         sectionHeader = [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:@"EventSectionHeader" forIndexPath:indexPath];         sectionHeader.layer.borderWidth = .5f;         sectionHeader.layer.borderColor = [UIColor colorWithRed:221.0 / 255.0 green:223.0 / 255.0 blue:220.0 / 255.0 alpha:1.0].CGColor;         if (indexPath.section == 0) {             sectionHeader.hidden = YES;          }else {             sectionHeader.hidden = NO;         }     }      return sectionHeader; } 

I even tried setting the frame for sectionHeader as @san said. But no luck. same result.

Answer 1

At last, I found an answer for my question. I have missed something. Anyway sorry for other fellow users.

I set the header height and width inside the below method till now as @san said.

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath 

But It is not the correct method to set the frame size of supplementary views. Later I found another method inside the flowLayout, which helps me to set the header and footer sizes.

This really works well for me:

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section {     if (section == 0) {         return CGSizeZero;     }else {         return CGSizeMake(CGRectGetWidth(collectionView.bounds), 135);     } } 

UPDATE: Since someone questioned about my skill in comments, attaching Apple Documentation link for returning CGSizeZero in above method.