swift - 使用 IGListKit 或 UICollectionView 每行多个部分

Question

我正在尝试以这种方式创建提要布局

[-------2/3-------][---1/3---] /* 2 items - 2 thirds and 1 third */
[---1/3---][-------2/3-------] /* 2 items - 1 third and 2 thirds */
[-------2/3-------][---1/3---] /* 2 items - 2 thirds and 1 third */
[---1/3---][-------2/3-------] /* 2 items - 1 third and 2 thirds */

我可以通过做类似的事情来实现这一目标

class FeedSectionController: ListSectionController {

    var entry: FeedEntry!

    override init() {
        super.init()
        inset = UIEdgeInsets(top: 0, left: 0, bottom: 15, right: 0)
    }

    override func numberOfItems() -> Int {
        return 2
    }

    override func sizeForItem(at index: Int) -> CGSize {

        guard let ctx = collectionContext else { return .zero }

        if index == 0 {
            return CGSize(width: ((ctx.containerSize.width / 3) * 2), height: 30)
        } else {
            return CGSize(width: (ctx.containerSize.width / 3), height: 30)
        }
    }

    override func cellForItem(at index: Int) -> UICollectionViewCell {
        let cell = UICollectionViewCell()
        cell.backgroundColor = index % 2 == 0 ? .lightGray : .darkGray

        return cell
    }

    override func didUpdate(to object: Any) {
        entry = object as? FeedEntry
    }
}

但是结果实际上更像

[-------2/3-------][---1/3---] /* 2 items - 2 thirds and 1 third */
[-------2/3-------][---1/3---] /* 2 items - 2 thirds and 1 third */
[-------2/3-------][---1/3---] /* 2 items - 2 thirds and 1 third */
[-------2/3-------][---1/3---] /* 2 items - 2 thirds and 1 third */

这不太正确，这也意味着我每个单元格每个部分有 2 个完整的 feed 项目。

我想要的是每个部分都包含 X 数量的单元格，这些单元格基本上构建了一个 feed 项目。

但是，为了做到这一点，我需要按照前面概述的方式布局 FeedSectionController，而不是 FeedSectionController 中的项目(我认为)。

Answer 1

我并不是 100% 熟悉 IGListKit，但您可以仅使用标准 UICollectionView 来创建该效果

class FeedViewController: UIViewController {

    private enum FeedItemWidth {
        case oneThird, twoThirds
    }

    private lazy var collectionView: UICollectionView = {
        let layout = UICollectionViewFlowLayout()
        let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
        cv.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "UICollectionViewCell")
        cv.backgroundColor = .gray
        cv.translatesAutoresizingMaskIntoConstraints = false
        return cv
    }()

    override func viewDidLoad() {
        super.viewDidLoad()

        collectionView.delegate = self
        collectionView.dataSource = self

        if let collectionViewLayout = collectionView.collectionViewLayout as? UICollectionViewFlowLayout {
            collectionViewLayout.minimumInteritemSpacing = 0
            collectionViewLayout.sectionInset = .init(top: 8, left: 8, bottom: 8, right: 8)
        }

        view.backgroundColor = .lightGray

        view.addSubview(collectionView)

        NSLayoutConstraint.activate([
            collectionView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor),
            collectionView.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor),
            collectionView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor),
            collectionView.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor)
        ])
    }

    override func viewWillLayoutSubviews() {
        super.viewWillLayoutSubviews()
        collectionView.collectionViewLayout.invalidateLayout()
    }

    private func feedItemWidth(_ type: FeedItemWidth) -> CGFloat {
        switch type {
        case .oneThird:
            return (collectionView.bounds.width / 3) - 12
        case .twoThirds:
            return  ((collectionView.bounds.width / 3) * 2) - 12
        }
    }
}

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

        let layoutOptions = [
            CGSize(width: feedItemWidth(.oneThird), height: 100),
            CGSize(width: feedItemWidth(.twoThirds), height: 100),
            CGSize(width: feedItemWidth(.twoThirds), height: 100),
            CGSize(width: feedItemWidth(.oneThird), height: 100)
        ]

        return layoutOptions[indexPath.item % layoutOptions.count]
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 8
    }

}

extension FeedViewController: UICollectionViewDataSource {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 35
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "UICollectionViewCell", for: indexPath)
        cell.backgroundColor = (indexPath.item % 2 == 0) ? .white : .black
        return cell
    }
}