我最终使用了NSCollectionLayoutGroup.custom，它允许您分别调整属于一个组的每个项目的大小。

let items = self.dataSource.snapshot().itemIdentifiers(inSection: 2)
                let group = NSCollectionLayoutGroup.custom(layoutSize: groupSize) { (env) -> [NSCollectionLayoutGroupCustomItem] in
                var customItems = [NSCollectionLayoutGroupCustomItem]()
                items.forEach { (object) in
                    switch object.imageURL {
                    case .none:
                        //calculate frame and append item
customItems.append(NSCollectionLayoutGroupCustomItem(frame: yourFrame))
                    case .some(_):
                        //calculate frame and append item
customItems.append(NSCollectionLayoutGroupCustomItem(frame: yourFrame))
                    }
                }
                return customItems
            }

有人在这里吗，我建议你试试

let item = NSCollectionLayoutItem(
    layoutSize: NSCollectionLayoutSize(
        widthDimension: .fractionalWidth(1),
        heightDimension: .estimated(128)
    )
)

let item2 = NSCollectionLayoutItem(
    layoutSize: NSCollectionLayoutSize(
        widthDimension: .fractionalWidth(1),
        heightDimension: .estimated(36)
    )
)

let group = NSCollectionLayoutGroup.vertical(
    layoutSize: NSCollectionLayoutSize(
        widthDimension: .fractionalWidth(1),
        heightDimension: .estimated(128)
    ),
    subitems: [item, item2]
)

我猜compos layout会自动计算item和item2的.estimated（）的height并应用该计算。