UICollectionView顶部单元格在设置键盘外观动画时消失

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(_:)), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(_:)), name: UIResponder.keyboardWillHideNotification, object: nil)

@objc func keyboardWillShow(_ notification: Notification) {
    // 更新UICollectionView的布局，使顶部单元格可见
    collectionView.collectionViewLayout.invalidateLayout()
}

@objc func keyboardWillHide(_ notification: Notification) {
    // 更新UICollectionView的布局，使顶部单元格可见
    collectionView.collectionViewLayout.invalidateLayout()
}

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
    if isKeyboardVisible {
        // 键盘弹出时，调整顶部单元格的位置
        return UIEdgeInsets(top: keyboardHeight, left: 0, bottom: 0, right: 0)
    } else {
        return UIEdgeInsets.zero
    }
}