Ios Swift 3：返回到发送数据的最后一个ViewController

我试图返回我的las viewController并发送数据，但它不起作用

当我只使用popViewController时，我可以返回页面，但不能将数据从B移到A

这是我的密码：

func goToLastViewController() {
    let vc = self.navigationController?.viewControllers[4] as! OnaylarimTableViewController
    vc.onayCode.userId = taskInfo.userId
    vc.onayCode.systemCode = taskInfo.systemCode

    self.navigationController?.popToViewController(vc, animated: true)
}

---

要将数据从子控制器传递到父控制器，必须使用委托模式传递数据

实现委派模式的步骤，假设A是父viewController，B是子viewController

创建协议，并在B中创建委托变量

扩展协议

当按下或显示viewcontroller时，将引用传递到A的B

在接收操作中定义委托方法

之后，根据您的条件，您可以从B调用委托方法

---

您应该使用

委托协议

class MyClass: NSUserNotificationCenterDelegate

具体实施如下：

func userDidSomeAction() {
    //implementation
}

当然，您必须在父类中实现deleget，比如

childView.delegate = self

查看此项了解更多信息

---

您必须使用2个选项发送回上一个ViewController

1.放松赛格。（使用情节提要）
您可以参考

2.使用委托/协议
您可以参考

也将对您有用。

您可以使用

例如，我有两个屏幕。第一个显示关于用户的信息，从那里，他进入屏幕选择他的城市。有关更改城市的信息应显示在第一个屏幕上

final class CitiesViewController: UITableViewController {
    // MARK: - Output -
    var onCitySelected: ((City) -> Void)?

    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        onCitySelected?(cities[indexPath.row])
    }
    ...
}

UserEditViewController：

final class UserEditViewController: UIViewController, UpdateableWithUser {
    // MARK: - Input -
    var user: User? { didSet { updateView() } }

    @IBOutlet private weak var userLabel: UILabel?

    private func updateView() {
        userLabel?.text = "User: \(user?.name ?? ""), \n"
                        + "City: \(user?.city?.name ?? "")"
    }
}

和协调员：

protocol UpdateableWithUser: class {
    var user: User? { get set }
}

final class UserEditCoordinator {

    // MARK: - Properties
    private var user: User { didSet { updateInterfaces() } }
    private weak var navigationController: UINavigationController?

    // MARK: - Init
    init(user: User, navigationController: UINavigationController) {
        self.user = user
        self.navigationController = navigationController
    }

    func start() {
        showUserEditScreen()
    }

    // MARK: - Private implementation
    private func showUserEditScreen() {
        let controller = UIStoryboard.makeUserEditController()
        controller.user = user
        controller.onSelectCity = { [weak self] in
            self?.showCitiesScreen()
        }
        navigationController?.pushViewController(controller, animated: false)
    }

    private func showCitiesScreen() {
        let controller = UIStoryboard.makeCitiesController()
        controller.onCitySelected = { [weak self] city in
            self?.user.city = city
            _ = self?.navigationController?.popViewController(animated: true)
        }
        navigationController?.pushViewController(controller, animated: true)
    }

    private func updateInterfaces() {
        navigationController?.viewControllers.forEach {
            ($0 as? UpdateableWithUser)?.user = user
        }
    }
}

coordinator = UserEditCoordinator(user: user, navigationController: navigationController)
coordinator.start()

然后我们只需要启动协调器：

protocol UpdateableWithUser: class {
    var user: User? { get set }
}

final class UserEditCoordinator {

    // MARK: - Properties
    private var user: User { didSet { updateInterfaces() } }
    private weak var navigationController: UINavigationController?

    // MARK: - Init
    init(user: User, navigationController: UINavigationController) {
        self.user = user
        self.navigationController = navigationController
    }

    func start() {
        showUserEditScreen()
    }

    // MARK: - Private implementation
    private func showUserEditScreen() {
        let controller = UIStoryboard.makeUserEditController()
        controller.user = user
        controller.onSelectCity = { [weak self] in
            self?.showCitiesScreen()
        }
        navigationController?.pushViewController(controller, animated: false)
    }

    private func showCitiesScreen() {
        let controller = UIStoryboard.makeCitiesController()
        controller.onCitySelected = { [weak self] city in
            self?.user.city = city
            _ = self?.navigationController?.popViewController(animated: true)
        }
        navigationController?.pushViewController(controller, animated: true)
    }

    private func updateInterfaces() {
        navigationController?.viewControllers.forEach {
            ($0 as? UpdateableWithUser)?.user = user
        }
    }
}

coordinator = UserEditCoordinator(user: user, navigationController: navigationController)
coordinator.start()

---

如果这是你以前的VC，你可以使用上面的代码。你想把数据发送回根视图控制器吗？