Question

我想将ViewControllerC中文本字段中的文本发送到ViewControllerA

中的另一个文本字段

使用委托我尝试将文字从ViewControllerC传递到ViewControllerA。

我无法在delegate?.userDidEnterInformation()

中获取逻辑内容ViewControllerC

任何人都可以帮我解决这个问题

ViewControllerC

protocol DataEnteredInDestinationDelegate: class {
    func userDidEnterInformation(info: String)
}

class DestinationSearchViewController: MirroringViewController {

var delegate: DataEnteredInDestinationDelegate?

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {

        let cell: UITableViewCell? = tableView.cellForRow(at: indexPath)
        componetsTextField.text = cell?.textLabel?.text

        delegate?.userDidEnterInformation()

        self.navigationController?.popToRootViewController(animated: true)
    }
}

ViewControllerA

class HomeViewController: MirroringViewController, DataEnteredInDestinationDelegate
{
    func userDidEnterInformation(info: String){
        locationView.destination.text = info
    }
}

Answer 1

delegate?.userDidEnterInformation(cell!.textLabel!.text)

此外，您应该设置ViewControllerC的代表。

viewControllerC.delegate = viewControllerA

Answer 2

首先，您必须始终将委托标记为weak，例如：

weak var delegate: DataEnteredInDestinationDelegate?

然后你需要像这样连接委托：

let vcA = ViewControllerA() 
let vcC = ViewControllerC()
vcC.delegate = vcA // Connect delegate

然后在调用此代码后，ViewControllerC中的委托方法将起作用：

delegate?.userDidEnterInformation(textString)

Answer 3

这里NotificationCentre可以是一个很好的方法，而不是代表。使Viewcontroller成为一个观察者，接收如下文本信息。

在viewDidLoad（）

中编写此代码

NotificationCenter.default.addObserver(self, selector: #selector(userDidEnterInformation(notification:)), name: NSNotification.Name.init(rawValue: "UserDidEnterInformation"), object: nil)

并在Viewcontroller A类中的任何地方写这个

func userDidEnterInformation(notification: Notification) {

    if let textInfo = notification.userInfo?["textInfo"] {
        textField.text = textInfo
    }
}

在Viewcontroller C中，通过编写下面的代码

发布带有textInfo的通知

NotificationCenter.default.post(name: NSNotification.Name.init(rawValue: "UserDidEnterInformation"), object: nil, userInfo: ["textInfo": textField.text])

Answer 4

考虑以下示例： -

let  aVCobjA = UIViewController()
let  aVCobjB = UIViewController()
let  aVCobjC = UIViewController()

var aNavigation = UINavigationController()

func pushVC()  {
    aNavigation.pushViewController(aVCobjA, animated: true)
    aNavigation.pushViewController(aVCobjB, animated: true)
    aNavigation.pushViewController(aVCobjC, animated: true)

    //Here you will get array of ViewControllers in stack of Navigationcontroller

    print(aNavigation.viewControllers)

    //To pass data from Viewcontroller C to ViewController A

    self.passData()

}

   // To pass data access stack of Navigation Controller as navigation controller provides a property viewControllers which gives you access of all view controllers that are pushed.

func passData()  {
    let aVCObj3 = aNavigation.viewControllers.last

    let aVCObj1 = aNavigation.viewControllers[0]

    //Now you have access to both view controller pass whatever data you want to pass
}

如何将文本域数据从第三个viewcontroller传递到第一个viewcontroller

4 个答案: