重用的自定义CollectionViewCells保留旧的大小属性

问题 我有过UICollectionView，实现方法。sizeForItemAt...我希望单元格具有分配给sizeForItemAt方法，但在重用单元格时，Size属性将保持不变。

所以我想知道是否有办法强迫可重复使用的细胞改变它们的高度？

截图 以下是链接：https://i.stack.imgur.com/33Fyf.png

代码： CellForItemat：

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

    cell.answerLetterButton.setTitleColor(Colors.answerLetterButtonColor, for: .normal)
    cell.letter = letters[indexPath.item]

    return cell
  }

sizeForItemAt：

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
    let answerCellHeightMultiplier: CGFloat = answer.count > 18 ? 0.28 : 0.37
    return CGSize(width: (self.frame.width / cellCount) - cellSpacing, height: self.frame.height * answerCellHeightMultiplier)
}

自定义UICollectionViewCell：

class AnswerLetterCell: UICollectionViewCell {

  var letter: String? {
    didSet {
      guard let letter = letter else { return }

      if letter != " " {
        answerLetterButton.setTitle(letter, for: .normal)
        answerLetterButton.isHidden = false
      } else {
        answerLetterButton.isHidden = true
      }
    }
  }

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

  func setup() {
    addSubview(answerLetterButton)

    let resizedLetterButton = Helpers.resizeImageSize(uiView: self, ratio: 42/48, multiplier: 1)

    /* Letter Button Constraints */
    answerLetterButton.centerXAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
    answerLetterButton.centerYAnchor.constraint(equalTo: self.centerYAnchor).isActive = true
    answerLetterButton.widthAnchor.constraint(equalToConstant: resizedLetterButton.width).isActive = true
    answerLetterButton.heightAnchor.constraint(equalToConstant: resizedLetterButton.height).isActive = true
  }

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

  /* Views */

  let answerLetterButton: UIButton = {
    let uiButton = UIButton()
    uiButton.translatesAutoresizingMaskIntoConstraints = false
    uiButton.setBackgroundImage(#imageLiteral(resourceName: "answer_letter_base.pdf"), for: .normal)
    uiButton.titleLabel?.font = Fonts.letterButtonFont
    uiButton.isUserInteractionEnabled = false
    return uiButton
  }()
}