UICollectionView doesn't scroll to bottom-CodePudding

I have an UICollectionView built programatically that doesn't allow me to scroll to the last item in it.

Here is how I set it up

private let collectionView: UICollectionView = UICollectionView(
        frame: .zero,
        collectionViewLayout: UICollectionViewCompositionalLayout { sectionIndex, _ -> NSCollectionLayoutSection? in
            return WorkoutListViewController.createSectionLayout(section: sectionIndex)
        })

private static func createSectionLayout(section: Int) -> NSCollectionLayoutSection {
        // item
        let item = NSCollectionLayoutItem(
            layoutSize: NSCollectionLayoutSize(
                widthDimension: .fractionalWidth(1.0),
                heightDimension: .fractionalHeight(1.0)
            )
        )
        item.contentInsets = NSDirectionalEdgeInsets(top: 14, leading: 0, bottom: 14, trailing: 0)
        
        // group
        let verticalGroup = NSCollectionLayoutGroup.vertical(
            layoutSize: NSCollectionLayoutSize(
                widthDimension: .fractionalWidth(1.0),
                heightDimension: .absolute(123)
            ),
            repeatingSubitem: item,
            count: 1
        )
        
        // section
        let section = NSCollectionLayoutSection(group: verticalGroup)
        return section
    }

private func configureCollectionView() {
        view.addSubview(collectionView)
        
        collectionView.register(
            WorkoutListCollectionViewCell.self,
            forCellWithReuseIdentifier: WorkoutListCollectionViewCell.identifier
        )
        collectionView.delegate = self
        collectionView.dataSource = self
        collectionView.backgroundColor = .systemBackground
    }

I tried modifying the height by giving it a very large number (e.g 2000) and nothing changed. I also tried adding the UICollectionViewDelegateFlowLayout protocol to add the

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        
    }

function and return the CGSize of my item.

CodePudding user response：

It seems your collection view is hiding behind the TabBar, So try to set the ContentInset of your collection view based on the bottom TabBar height.

Example:

collectionView.contentInset = .init(top: 0.0, left: 0.0, bottom: bottomHeight, right: 0.0)

Hope this helps!