如何修复 UICollectionView 单元格中的致命错误？

Question

我在storyboard 中有MasterViewController 和UICollectionView。我将此代码用于我的UICollectionView：

MasterViewController：

class MasterViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout, URLSessionDownloadDelegate, SKProductsRequestDelegate, SKStoreProductViewControllerDelegate {

@IBOutlet weak var collectionView: UICollectionView?

fileprivate var currentPage: Int = 0
    fileprivate var pageSize: CGSize {
        let layout = UPCarouselFlowLayout()
        var pageSize = layout.itemSize
        pageSize.width += layout.minimumLineSpacing
        return pageSize
    }

override func viewDidLoad() {
        super.viewDidLoad()

        self.addCollectionView()
        self.setupLayout()
}

func setupLayout(){

        let pointEstimator = RelativeLayoutUtilityClass(referenceFrameSize: self.view.frame.size)

        self.collectionView?.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true
        self.collectionView?.topAnchor.constraint(equalTo: self.view.topAnchor, constant: pointEstimator.relativeHeight(multiplier: 0.1754)).isActive = true
        self.collectionView?.widthAnchor.constraint(equalTo: self.view.widthAnchor).isActive = true
        self.collectionView?.heightAnchor.constraint(equalToConstant: pointEstimator.relativeHeight(multiplier: 0.6887)).isActive = true

        self.currentPage = 0
    }

    func addCollectionView(){

        let pointEstimator = RelativeLayoutUtilityClass(referenceFrameSize: self.view.frame.size)

        let layout = UPCarouselFlowLayout()

        layout.itemSize = CGSize(width: pointEstimator.relativeWidth(multiplier: 0.73333), height: 400)

        layout.scrollDirection = .horizontal

        self.collectionView = UICollectionView(frame: .zero, collectionViewLayout: layout)

        self.collectionView?.translatesAutoresizingMaskIntoConstraints = false

        self.collectionView?.delegate = self
        self.collectionView?.dataSource = self

        self.collectionView?.register(MasterViewCell.self, forCellWithReuseIdentifier: "Cell")


        let spacingLayout = UPCarouselFlowLayout()
        spacingLayout.spacingMode = UPCarouselFlowLayoutSpacingMode.overlap(visibleOffset: 20)
    }

MasterViewCell：

class MasterViewCell: UICollectionViewCell {
    let customView: UIView = {
        let view = UIView()
        view.translatesAutoresizingMaskIntoConstraints = false
        view.layer.cornerRadius = 12
        return view
    }()
    var cellImageView: UIImageView!


    override init(frame: CGRect) {
        super.init(frame: frame)

        self.addSubview(self.customView)

        self.customView.centerXAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
        self.customView.centerYAnchor.constraint(equalTo: self.centerYAnchor).isActive = true
        self.customView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 1).isActive = true
        self.customView.heightAnchor.constraint(equalTo: self.heightAnchor, multiplier: 1).isActive = true


    }

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

RelativeLayoutUtilityClass：

class RelativeLayoutUtilityClass {

    var heightFrame: CGFloat?
    var widthFrame: CGFloat?

    init(referenceFrameSize: CGSize){
        heightFrame = referenceFrameSize.height
        widthFrame = referenceFrameSize.width
    }

    func relativeHeight(multiplier: CGFloat) -> CGFloat{

        return multiplier * self.heightFrame!
    }

    func relativeWidth(multiplier: CGFloat) -> CGFloat{
        return multiplier * self.widthFrame!

    }

但我在MasterViewCell: *Thread 1: Fatal error: init(coder:) has not been implemented* 有这个错误

如何解决？

Answer 1

您尚未实现 init(coder:) 初始化程序，如您在此处看到的：

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

您似乎正在从情节提要中加载一些单元格，因此您不能只在此处使用fatalError。

实现应该很简单。您可以像在 init(frame:) 初始化程序中那样做同样的事情：

class MasterViewCell: UICollectionViewCell {
    let customView: UIView = {
        let view = UIView()
        view.translatesAutoresizingMaskIntoConstraints = false
        view.layer.cornerRadius = 12
        return view
    }()
    var cellImageView: UIImageView!


    override init(frame: CGRect) {
        super.init(frame: frame)
        commonInit()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        commonInit()
    }

    private func commonInit() {
        self.addSubview(self.customView)

        self.customView.centerXAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
        self.customView.centerYAnchor.constraint(equalTo: self.centerYAnchor).isActive = true
        self.customView.widthAnchor.constraint(equalTo: self.widthAnchor, multiplier: 1).isActive = true
        self.customView.heightAnchor.constraint(equalTo: self.heightAnchor, multiplier: 1).isActive = true
    }
}