swift - CollectionViewCell 不显示单元格或加载核心数据字符串

Question

我正在尝试通过第一类保存核心数据字符串，然后将该字符串加载到 collectionviewcell 文本标签中。我在不使用任何 Storyboard的情况下完成所有这些工作。我没有收到任何编译错误。就在我加载这个类时，什么也没有出现。

这是我的 git 配置文件的链接 https://github.com/redrock34/collectionViewCellLoad .

class ViewController: UIViewController {

    var itemsName: [Item] = []
    weak var collectionView: UICollectionView!


    override func loadView() {
        super.loadView()

        let collectionView = UICollectionView(frame: .zero, collectionViewLayout: UICollectionViewFlowLayout())
        collectionView.translatesAutoresizingMaskIntoConstraints = false
        self.view.addSubview(collectionView)
        NSLayoutConstraint.activate([
            self.view.topAnchor.constraint(equalTo: collectionView.topAnchor),
            self.view.bottomAnchor.constraint(equalTo: collectionView.bottomAnchor),
            self.view.leadingAnchor.constraint(equalTo: collectionView.leadingAnchor),
            self.view.trailingAnchor.constraint(equalTo: collectionView.trailingAnchor),
            ])
        self.collectionView = collectionView
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        self.collectionView.dataSource = self
        self.collectionView.delegate = self
        self.collectionView.register(Cell.self, forCellWithReuseIdentifier: Cell.identifier)
        self.collectionView.alwaysBounceVertical = true
        self.collectionView.backgroundColor = .brown

        collectionView.reloadData()

    }
}

extension ViewController: UICollectionViewDataSource {

    func collectionView(_ collectionView: UICollectionView,
                        numberOfItemsInSection section: Int) -> Int {
        return self.itemsName.count
    }

    func collectionView(_ collectionView: UICollectionView,
                        cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: Cell.identifier, for: indexPath) as! Cell

        let user = itemsName[indexPath.row]
        cell.textLabel?.text = ("\nCourse: \(user.atBATS!) Score: ")
        cell.backgroundColor = UIColor.blue
        cell.textLabel.textColor = UIColor.black
            return cell

    }
}

Answer 1

你有一个空的数据源

var itemsName: [Item] = []