Ios 如何在 Swift 中从另一个视图控制器将元素附加到数组中

原因是每次加载UserTableViewController时，都会创建一个新的itemArray.解决此问题的最简单方法是将RegisterViewController设置为表视图数据源和委托.您只需要将register view controller实例传递给tableview，而不是传递userData.试着这样做:

class RegisterViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
    @IBOutlet weak var usernameText: UITextField!
    var items: [Item] = []
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        items.count
    }
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "cellID", for: indexPath)
        var content = cell.defaultContentConfiguration()
        content.text = items[indexPath.row].userRegister
        cell.contentConfiguration = content
        return cell
    }
    @IBAction func didTapSave(_ sender: Any) {
        usernameText.endEditing(true)
        items.append(.init(userRegister: usernameText.text!))
        performSegue(withIdentifier: "goToData", sender: self)
    }
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "goToData" {
            let destinationVC = segue.destination as! UserTableViewController
            destinationVC.registerViewController = self
        }
    }
}

以及您的UserTableViewController:

class UserTableViewController: UIViewController {
    @IBOutlet weak var tableView: UITableView!
    var registerViewController: RegisterViewController?
    override func viewDidLoad() {
        super.viewDidLoad()   
        tableView.register(UITableViewCell.self, forCellReuseIdentifier: "cellID")
        tableView.delegate = registerViewController
        tableView.dataSource = registerViewController
    }
}