ios - 如何使用 swift 中的委托(delegate)将第二个 View Controller 文本字段值添加到第三个 View Controller 按钮中的第一个 View Controller 标签

Question

我有三个 View Controller 。在这里，我想从第三个 View Controller 完成按钮将第二个 View Controller 文本字段值添加到第一个 View Controller TableView 标签。我可以在 popviewcontroller 时使用委托(delegate)将第二个 View Controller 文本字段添加到第一个 View Controller 标签，但我无法从第三个 View Controller 按钮添加。请帮助我编写代码。

这是我的代码:

这是我的第一个 VC 代码:

import UIKit
class EmployeeViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, EmployeeDelegateProtocol {


var namesArray = [String]()
@IBOutlet weak var tableView: UITableView!

override func viewDidLoad() {
    super.viewDidLoad()
    tableView.delegate = self
    tableView.dataSource = self
}
    func sendDataToEmployeeViewController(myData: String) {
    self.namesArray.append(myData)
    tableView.reloadData()
    print(namesArray)
    print("in delegate method \(namesArray)")
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return namesArray.count
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

    let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! EmployeeTableViewCell
    cell.empName.text = namesArray[indexPath.row]
    return cell
}

@IBAction func addButtonClicked(_ sender: Any) {
    let empProfileVC = self.storyboard!.instantiateViewController(withIdentifier: "EmployeeProfileViewController") as! EmployeeProfileViewController
    empProfileVC.delegate = self
    self.navigationController?.pushViewController(empProfileVC, animated: true)
}
}

这是我的第二个 VC 代码:

使用 pop 时它正在工作

import UIKit

protocol EmployeeDelegateProtocol {
func sendDataToEmployeeViewController(myData: String)
}

class EmployeeProfileViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, UINavigationControllerDelegate,UIImagePickerControllerDelegate {

var delegate: EmployeeDelegateProtocol?

@IBOutlet weak var firstNameTextField: UITextField!
@IBOutlet weak var tableView: UITableView!

override func viewDidLoad() {
    super.viewDidLoad()
}
@objc func saveButtonClicked(){
    print("button clicked")
    self.delegate?.sendDataToEmployeeViewController(myData: firstNameTextField.text!)
    //self.navigationController?.popViewController(animated: true)
}
}

但我想从thirdVc完成按钮发送值:

import UIKit

class EmployeeProfilecreatedPopUpViewController: UIViewController {
var cellProfile: EmployeeProfileViewController?
override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.
}

@IBAction func doneButtonTapped(_ sender: Any) {

    print("done tapped")
    let empVC = self.storyboard!.instantiateViewController(withIdentifier: "EmployeeViewController") as! EmployeeViewController        self.navigationController?.pushViewController(empVC, animated: true)
}
}

请建议我如何从thirdvc完成按钮发送。

Answer 1

第一个 View Controller

import UIKit

class EmployeeViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, EmployeeDelegateProtocol {

    //MARK:- ----- Outlets and variables ------
    @IBOutlet weak var tableView: UITableView!
    var namesArray = [String]()


    //MARK:- ----- View lifecycle -----
    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.delegate = self
        tableView.dataSource = self
    }

    //MARK:- ----- TableView Datasource ------
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return namesArray.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! EmployeeTableViewCell
        cell.empName.text = namesArray[indexPath.row]
        return cell
    }

    //MARK:- ----- Button Actions ------
    @IBAction func addButtonClicked(_ sender: Any) {

        let empProfileVC = self.storyboard!.instantiateViewController(withIdentifier: "EmployeeProfileViewController") as! EmployeeProfileViewController
        empProfileVC.delegate = self
        self.navigationController?.pushViewController(empProfileVC, animated: true)
    }

    //MARK:- ----- Employee delegate ------
    func popController(_ controller: UIViewController, withData: String) {

        self.namesArray.append(myData)
        tableView.reloadData()
        print(namesArray)
        print("in delegate method \(namesArray)")

        controller.navigationController?.popViewController(animated: false)
    }
}

第二 View Controller

import UIKit

protocol EmployeeDelegateProtocol {
    func popController(_ controller: UIViewController, withData: String)
}

 class EmployeeProfileViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, UINavigationControllerDelegate, UIImagePickerControllerDelegate, EmployeeProfileDelegate {

    //MARK:- ----- Outlets and variables ------
    var delegate: EmployeeDelegateProtocol?
    @IBOutlet weak var firstNameTextField: UITextField!
    @IBOutlet weak var tableView: UITableView!


    //MARK:- ----- View lifecycle -----
    override func viewDidLoad() {
        super.viewDidLoad()
    }

    //MARK:- ----- Button Actions ------
    @objc func saveButtonClicked() {
        let popUpVC = self.storyboard!.instantiateViewController(withIdentifier: "EmployeeProfilecreatedPopUpViewController") as! EmployeeProfilecreatedPopUpViewController
        popUpVC.delegate = self
        self.navigationController?.pushViewController(popUpVC, animated: true)
        // OR
        self.present(popUpVC, animated: true) { }

        /*print("button clicked")
        self.delegate?.sendDataToEmployeeViewController(myData: firstNameTextField.text!)*/
        //self.navigationController?.popViewController(animated: true)
    }


    //MARK:- ----- Employee profile delegate ------
    func popController(_ controller: UIViewController) {

        self.delegate?.popController(self, withData: firstNameTextField.text!)
        controller.navigationController?.popViewController(animated: false)

        // OR

        controller.dismiss(animated: true) {
            self.delegate?.popController(self, withData: self.firstNameTextField.text!)
        }
    }
}

第三 View Controller

import UIKit

protocol EmployeeProfileDelegate {
    func popController(_ controller: UIViewController)
}

class EmployeeProfilecreatedPopUpViewController: UIViewController {

    //MARK:- ----- Outlets and variables ------
    var delegate: EmployeeProfileDelegate?


    //MARK:- ----- View lifecycle -----
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }

    //MARK:- ----- Button Actions ------
    @IBAction func doneButtonTapped(_ sender: Any) {

        self.delegate?.popController(self)
        /*print("done tapped")
        let empVC = self.storyboard!.instantiateViewController(withIdentifier: "EmployeeViewController") as! EmployeeViewController
        self.navigationController?.pushViewController(empVC, animated: true)*/
    }
}

如果您对 SecondViewController 到 ThirdCiewControler 使用 segue，请参阅 unwind segue:Transition to UITabBarController

在从 ThirdViewController 到 SecondViewController unwind segue 后，调用委托(delegate)方法将数据从 SecondViewController 传递到 FirstViewController.