滚动后UITableViewCell内容消失

import UIKit

class MyTableViewCell: UITableViewCell {
    let titleLabel = UILabel()
    let subtitleLabel = UILabel()

    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        setupViews()
    }

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

    private func setupViews() {
        contentView.addSubview(titleLabel)
        contentView.addSubview(subtitleLabel)

        // 设置布局约束
        titleLabel.translatesAutoresizingMaskIntoConstraints = false
        subtitleLabel.translatesAutoresizingMaskIntoConstraints = false

        NSLayoutConstraint.activate([
            titleLabel.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 8),
            titleLabel.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 16),
            titleLabel.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -16),

            subtitleLabel.topAnchor.constraint(equalTo: titleLabel.bottomAnchor, constant: 4),
            subtitleLabel.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 16),
            subtitleLabel.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -16),
            subtitleLabel.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -8)
        ])
    }

    func configure(with title: String, subtitle: String) {
        titleLabel.text = title
        subtitleLabel.text = subtitle
    }
}

class MyViewController: UIViewController, UITableViewDataSource {
    let tableView = UITableView()
    var data = ["Item 1", "Item 2", "Item 3", "Item 4", "Item 5"]

    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.dataSource = self
        view.addSubview(tableView)

        // 设置布局约束
        tableView.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            tableView.topAnchor.constraint(equalTo: view.topAnchor),
            tableView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
            tableView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            tableView.trailingAnchor.constraint(equalTo: view.trailingAnchor)
        ])
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return data.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "MyCell", for: indexPath) as! MyTableViewCell
        let item = data[indexPath.row]
        cell.configure(with: item, subtitle: "Subtitle for \(item)")
        return cell
    }
}