UiCollectionView不显示

Question

我正在尝试制作一个简单的collectionView，由于某种原因，它根本没有显示。 我通过我创建的字符串列表（页面）将图像设置为我创建的一些自定义单元格（ProfileCells）。 问题在于不仅不显示单元格，而且集合视图也没有显示（我将背景设置为绿色进行测试）

extension ProfileController: UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return pages.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! ProfileCell
            let page = pages[indexPath.item]
            print("something",page)
            cell.setImage(image: page)
            return cell
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        print (CGSize(width: view.frame.width, height: view.frame.height))
        return CGSize(width: view.frame.width, height: view.frame.height)
    }
}

“ loginButton”只是我要引用的虚拟图像，出现在Collectionview单元格中。

let cellId = "cellId"

let pages: [String] = {
    let firstPage = "loginButton"
    let secondPage = "loginButton"
    let thirdPage = "loginButton"
    return [firstPage,secondPage,thirdPage]
}()

lazy var collectionView: UICollectionView = {
    let layout = UICollectionViewFlowLayout()
    layout.headerReferenceSize = CGSize.zero
    layout.scrollDirection = .horizontal
    layout.minimumLineSpacing = 0
    let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
    cv.backgroundColor = UIColor.green
    cv.dataSource = self
    cv.delegate = self
    cv.isPagingEnabled = true
    cv.showsHorizontalScrollIndicator = false
    cv.showsVerticalScrollIndicator = false

    return cv
}()

collectionView是我创建的stackview的子视图（为简洁起见，此处未显示），即使stackView内部的所有其他子视图都起作用

override func viewDidLoad() {
    super.viewDidLoad()
   view.addSubview(stackView)
   collectionView.register(ProfileCell.self, forCellWithReuseIdentifier: cellId)
}

这是我为CollectionViewCells制作的Custom类

class ProfileCell: UICollectionViewCell{
    //Integrate the page class into collectionviewcell
    var image: String?

    func setImage(image: String) {
        imageView.image = UIImage(named:image)
    }
    override init(frame: CGRect) {
        super.init(frame: frame)
        setupViews()
    }

    //Here I select the image I want to use in collectionview
    var imageView: UIImageView = {
        let iv = UIImageView()
        iv.contentMode = .scaleAspectFill
        iv.backgroundColor = UIColor.gray
        iv.clipsToBounds = true
        return iv
    }()

    //Setting up all views within collectionview
    func setupViews() {
        backgroundColor = UIColor.gray
        addSubview(imageView)
        imageView.anchorWithConstantsToTop(top: topAnchor, left: leftAnchor, bottom: bottomAnchor, right: rightAnchor, topConstant: 0, leftConstant: 0, bottomConstant: 0, rightConstant: 0)
        imageView.heightAnchor.constraint(equalToConstant: 50)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}