Centers Collection View Content

center-collection-view.swift

extension CommunityConnectViewController: UICollectionViewDelegateFlowLayout {
    func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAtIndex section: Int) -> UIEdgeInsets {
        
        // Translated from Objective-C version at: http://stackoverflow.com/a/27656363/309736
        
        let cellCount = CGFloat(viewModel.getNumOfItemsInSection(0))
        
        if cellCount > 0 {
            let flowLayout = collectionViewLayout as! UICollectionViewFlowLayout
            let cellWidth = flowLayout.itemSize.width + flowLayout.minimumInteritemSpacing
            let totalCellWidth = cellWidth * cellCount
            let contentWidth = collectionView.frame.size.width - collectionView.contentInset.left - collectionView.contentInset.right
            
            if (totalCellWidth < contentWidth) {
                let padding = (contentWidth - totalCellWidth) / 2.0
                return UIEdgeInsetsMake(0, padding, 0, padding)
            }
        }
        
        return UIEdgeInsetsZero
    }
}