How can I enable/disable section headers in UIColl

问题:

How can I enable/disable section headers in UICollectionView programmatically?

It can be easily done easily done in Storyboard (checkbox), but how about doing it in code?

回答1:

You can either use the collectionView:layout:referenceSizeForHeaderInSection: method of the UICollectionViewDelegateFlowLayout and return CGSizeMake(0,0) or set accordingly the headerReferenceSize of UICollectionViewFlowLayout.

Edit: headerReferenceSize is actually the property that storyboard uses to show/hide the headers. I've added the relevant lines from the Storyboard file

With section checkbox on:

 <collectionViewFlowLayout key="collectionViewLayout" minimumLineSpacing="10" minimumInteritemSpacing="10" id="xAt-Uo-bMl">
           <size key="headerReferenceSize" width="50" height="50"/></collectionViewFlowLayout>

With section checkbox off

 <collectionViewFlowLayout key="collectionViewLayout" minimumLineSpacing="10" minimumInteritemSpacing="10" id="xAt-Uo-bMl">
           <size key="headerReferenceSize" width="0" height="0"/></collectionViewFlowLayout>

Edit #2:

From the official docs:

Each section in a flow layout can have its own custom header and footer. To configure the header or footer for a view, you must configure the size of the header or footer to be non zero. You can do this by implementing the appropriate delegate methods or by assigning appropriate values to the headerReferenceSize and footerReferenceSize properties. If the header or footer size is 0, the corresponding view is not added to the collection view.

回答2:

Just change the height to 0 of the headers you don't want to show...

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section
{
    if (section == 0) {
        return CGSizeZero;
    }else {
        return CGSizeMake(collectionView.frame.size.width,50);
    }
}

回答3:

Neither nil nor [UIView new] works an both throw the same error. The best answer is in How to change the UICollectionView footerview's height programatically

回答4:

When you simply don't want an header to appear, in the delegate's

viewForSupplementaryElementOfKind

Just return [UIView new]; when kind == UICollectionElementKindSectionHeader:

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
{   
    if (kind == UICollectionElementKindSectionHeader) {
       return [UIView new]; // Or even nil, I think it would work.
    }
    ...
    return /*something else that you want to return*/ ;
}