Swift 单元已创建但未显示在 UICollectionView swift 5

Question

我正在使用自定义集合视图单元格创建集合视图。 因此，我在 storyboard 视图 controller 中创建了集合视图。 问题是我的单元格是在 cellForItemAt 中创建的，但它们根本没有显示，我也尝试过使用默认单元格，但它们也没有显示，当然，我已经尝试了我找到的所有解决方案。 感谢您提前提供帮助！

查看 controller class 相关零件

   override func viewDidLoad() {
        super.viewDidLoad()
        
        collectionView.delegate = self
        collectionView.dataSource = self
        
        title = set?.name
        
        
        
        collectionView!.register(WordCollectionViewCell.self, forCellWithReuseIdentifier: Identifies.WordCollectionViewCellIdentifier)
        
        
        let buttonItem  = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(addButtonPressed))
        
        
        navigationItem.rightBarButtonItem = buttonItem
        updateTranslations()
    }

hide: false 控制台: true babel: false -->

extension SingleSetViewController : UICollectionViewDelegate, UICollectionViewDataSource  {
    
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        print(translations.count)
        return translations.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: Identifies.WordCollectionViewCellIdentifier, for: indexPath) as! WordCollectionViewCell
        
    
        cell.translation = translations[indexPath.row]
    
        return cell
    }
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 1 
    }
}

集合视图单元 class

class WordCollectionViewCell: UICollectionViewCell {
    @IBOutlet weak var wordLabel: UILabel!
    
    private var showsWord = true
    
    
    private var _translation : Translation?
    var translation : Translation  {
        set {
            _translation = newValue
        }
        get {
            return _translation ?? Translation(word: "", translation: "")
        }
    }
    override func awakeFromNib() {
        super.awakeFromNib()
        
        let gestureRecognizer = UITapGestureRecognizer(target: self , action: #selector(flip))
        gestureRecognizer.numberOfTapsRequired = 1
        self.addGestureRecognizer(gestureRecognizer)
        
        wordLabel.text = _translation?.word
    }
    
    @objc private func flip(_ sender: UIGestureRecognizer){
        let options : UIView.AnimationOptions = [.transitionFlipFromRight]
        UIView.transition(with: self, duration: 0.5, options: options){
            if let translation = self._translation {
                    self.wordLabel.text = self.showsWord ? translation.translation : translation.word
                    self.showsWord = !self.showsWord
            }
        }
    }
    
    static func nib() -> UINib {
        return UINib(nibName: NibNames.WordCollectionViewCellNibName, bundle: nil)
    }
}

Answer 1

您的awakeFromNib方法可能在您设置单元格的translation属性之前触发。 尝试在翻译的设置器中设置 label 文本：

    set {
        _translation = newValue
        wordLabel?.text = _translation?.word
    }