CollectionView

UICollectionView using UICollectionViewCompositionalLayout

1. create UICollectionViewCompositionalLayout and add NSCollectionLayoutSection
2. NSCollectionLayoutSection create with multiple NSCollectionLayoutGroup
3. NSCollectionLayoutGroup set as horizontal or vertical
4. NSCollectionLayoutGroup set multiple sub NSCollectionLayoutGroup
5. NSCollectionLayoutGroup set multiple NSCollectionLayoutItem
6. UICollectionView set collectionViewLayout

UICollectionView with two column and mulitple row without UICollectionViewLayout size func getCompositionalLayout() -> UICollectionViewCompositionalLayout {

    //--------- Group 1 Item 1 ---------//
    
    let group1Item1Sub1 = NSCollectionLayoutItem(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1/2), heightDimension: .fractionalHeight(1)))
    group1Item1Sub1.contentInsets = NSDirectionalEdgeInsets(top: 5, leading: 5, bottom: 5, trailing: 5)
    let group1Item1Sub2 = NSCollectionLayoutItem(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1/2), heightDimension: .fractionalHeight(1)))
    group1Item1Sub2.contentInsets = NSDirectionalEdgeInsets(top: 5, leading: 5, bottom: 5, trailing: 5)
    
    let group1 = NSCollectionLayoutGroup.horizontal(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension: .fractionalHeight(1)), subitems: [group1Item1Sub1,group1Item1Sub2])
    
    let containerGroup = NSCollectionLayoutGroup.vertical(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension:  .fractionalWidth(1/2)), subitems: [ group1])

    let section = NSCollectionLayoutSection(group: containerGroup)
    let layout = UICollectionViewCompositionalLayout(section: section)
    return layout
    
}

func getCompositionalLayout() -> UICollectionViewCompositionalLayout {
    //--------- Group1 Item 1 ---------//
    
    let group1Item1Sub1 = NSCollectionLayoutItem(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension: .fractionalHeight(1/2)))
    group1Item1Sub1.contentInsets = NSDirectionalEdgeInsets(top: 1, leading: 1, bottom: 1, trailing: 1)
    let group1Item1Sub2 = NSCollectionLayoutItem(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension: .fractionalHeight(1/2)))
    group1Item1Sub2.contentInsets = NSDirectionalEdgeInsets(top: 1, leading: 1, bottom: 1, trailing: 1)
    
    let group1Item1 = NSCollectionLayoutGroup.vertical(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1/3), heightDimension: .fractionalHeight(1)), subitems: [group1Item1Sub2,group1Item1Sub1])
    group1Item1.contentInsets = NSDirectionalEdgeInsets(top: 1, leading: 1, bottom: 1, trailing: 1)
    
    //--------- Group1 Item 2 ---------//
    
    let group1Item2 = NSCollectionLayoutItem(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(2/3), heightDimension: .fractionalHeight(1)))
    group1Item2.contentInsets = NSDirectionalEdgeInsets(top: 1, leading: 1, bottom: 1, trailing: 1)
    
    //--------- Add Group Item 1 ---------//
    let group1 = NSCollectionLayoutGroup.horizontal(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension: .fractionalHeight(1/2)), subitems: [group1Item1,group1Item2])
    
    //--------- Group 2 Item 1 ---------//
    
    let group2Item1Sub1 = NSCollectionLayoutItem(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension: .fractionalHeight(1/2)))
    group2Item1Sub1.contentInsets = NSDirectionalEdgeInsets(top: 1, leading: 1, bottom: 1, trailing: 1)
    let group2Item1Sub2 = NSCollectionLayoutItem(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension: .fractionalHeight(1/2)))
    group2Item1Sub2.contentInsets = NSDirectionalEdgeInsets(top: 1, leading: 1, bottom: 1, trailing: 1)
    
    let group2Item1 = NSCollectionLayoutGroup.vertical(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1/3), heightDimension: .fractionalHeight(1)), subitems: [group2Item1Sub1,group2Item1Sub2])
    
    //--------- Group 2 Item 2 ---------//
    let group2Item2Sub1 = NSCollectionLayoutItem(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension: .fractionalHeight(1/2)))
    group2Item2Sub1.contentInsets = NSDirectionalEdgeInsets(top: 1, leading: 1, bottom: 1, trailing: 1)
    let group2Item2Sub2 = NSCollectionLayoutItem(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension: .fractionalHeight(1/2)))
    group2Item2Sub2.contentInsets = NSDirectionalEdgeInsets(top: 1, leading: 1, bottom: 1, trailing: 1)
    
    let group2Item2 = NSCollectionLayoutGroup.vertical(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1/3), heightDimension: .fractionalHeight(1)), subitems: [group2Item2Sub1,group2Item2Sub2])
    group2Item2.contentInsets = NSDirectionalEdgeInsets(top: 1, leading: 1, bottom: 1, trailing: 1)
    
    //--------- Group 2 Item 3 ---------//
    
    let group2Item3Sub1 = NSCollectionLayoutItem(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension: .fractionalHeight(1/2)))
    group2Item3Sub1.contentInsets = NSDirectionalEdgeInsets(top: 1, leading: 1, bottom: 1, trailing: 1)
    let group2Item3Sub2 = NSCollectionLayoutItem(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension: .fractionalHeight(1/2)))
    group2Item3Sub2.contentInsets = NSDirectionalEdgeInsets(top: 1, leading: 1, bottom: 1, trailing: 1)
    
    let group2Item3 = NSCollectionLayoutGroup.vertical(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1/3), heightDimension: .fractionalHeight(1)), subitems: [group2Item3Sub1,group2Item3Sub2])
    group2Item3.contentInsets = NSDirectionalEdgeInsets(top: 1, leading: 1, bottom: 1, trailing: 1)
    //--------- Add Group Item 2 ---------//
    let group2 = NSCollectionLayoutGroup.horizontal(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension: .fractionalHeight(1/2)), subitems: [group2Item1, group2Item2,group2Item3])
    
    
    //--------- Container Group ---------//
    let containerGroup = NSCollectionLayoutGroup.vertical(layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1), heightDimension: .absolute(600)), subitems: [ group1, group2])

    let section = NSCollectionLayoutSection(group: containerGroup)
    let layout = UICollectionViewCompositionalLayout(section: section)
    return layout
    
    
}