Expanding cell

CustomCell.swift

import UIKit

class NewSongExpandableTableViewCell: UITableViewCell {

    @IBOutlet var firstView: UIView!
    @IBOutlet var secondView: UIView!
    
    @IBOutlet var heightConstraintSecondView: NSLayoutConstraint!
    
    
    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
    }

    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)

        // Configure the view for the selected state
    }
    
    var showSong = false {
        didSet {
            heightConstraintSecondView.priority = showSong ? 250 : 999
        }
    }

}

TableViewController.swift

override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
      if selectedIndex == indexPath.row {
          return 210
      } else {
          return 84
      }
  }
    
  override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
      if selectedIndex == indexPath.row {
          selectedIndex = -1
      } else {
          selectedIndex = indexPath.row
      }
      self.tableView.beginUpdates()
      self.tableView.reloadRows(at: [indexPath], with: UITableViewRowAnimation.automatic)
      self.tableView.endUpdates()
  }

MIJN CODE IS BETER