在不使用自动布局的情况下调整UITableView标题的大小

tableView.delegate = self

func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
    let headerView = UIView()
    headerView.backgroundColor = .lightGray
    
    let titleLabel = UILabel()
    titleLabel.font = UIFont.systemFont(ofSize: 20) // 设置标题字体大小
    titleLabel.text = "Section \(section + 1)"
    titleLabel.textColor = .black
    titleLabel.translatesAutoresizingMaskIntoConstraints = false
    headerView.addSubview(titleLabel)
    
    // 添加约束，使标题居中显示
    titleLabel.centerXAnchor.constraint(equalTo: headerView.centerXAnchor).isActive = true
    titleLabel.centerYAnchor.constraint(equalTo: headerView.centerYAnchor).isActive = true
    
    return headerView
}

func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
    return 50 // 设置标题的高度
}