How to add Header with Supplementary view to UiCollectionView in Objective-C? - ios

Question

I have a ViewController that contain a CollectionView :
- (void)viewDidLoad
{
UICollectionViewFlowLayout *layout = [UICollectionViewFlowLayout new];
collectionview = [[UICollectionView alloc]initWithFrame:CGRectZero collectionViewLayout:layout];
collectionview.backgroundColor = [UIColor colorWithRed:0.86 green:0.86 blue:0.86 alpha:1.0];
collectionview.translatesAutoresizingMaskIntoConstraints = false;
collectionview.delegate = self;
collectionview.dataSource = self;
collectionview.bounces = true;
[collectionview registerClass:[CollectionViewCell1 class] forCellWithReuseIdentifier:#"cell1"];
[self.view addSubview:collectionview];
[collectionview sdc_alignEdgesWithSuperview:UIRectEdgeAll];
[collectionview registerClass:[RecipeCollectionReusableView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:#"HeaderView"];
}
-(UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
{
UICollectionReusableView *reusableview = nil;
RecipeCollectionReusableView *headerView = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:#"HeaderView" forIndexPath:indexPath];
headerView.backgroundColor = [UIColor greenColor];
headerView.title.text = #"ABC";
reusableview = headerView;
return reusableview;
}
and RecipeCollectionReusableView is :
- (void)initialize
{
_title = [UILabel new];
_title.translatesAutoresizingMaskIntoConstraints = false;
[self addSubview:_title];
[_title sdc_centerInSuperview];
}
but there isn't any header on the screen after run.

Answer 1

Did you do the required implementation for the header?
https://developer.apple.com/documentation/uikit/uicollectionviewdelegateflowlayout/1617702-collectionview?language=objc
collectionView:layout:referenceSizeForHeaderInSection:
Return Value
The size of the header. If you return a value of size (0, 0), no header is added.
Discussion
If you do not implement this method, the flow layout uses the value in its
headerReferenceSize
property to set the size of the header.
During layout, only the size that corresponds to the appropriate scrolling direction is used. For example, for the vertical scrolling direction, the layout object uses the height value returned by your method. (In that instance, the width of the header would be set to the width of the collection view.) If the size in the appropriate scrolling dimension is 0, no header is added.

Answer 2

This article completely helped me :
How to add Header wit Supplementary view to UiCollectionView in Objective-C