使用委托将数据传回之前的 VC 并更新自定义单元格

Question

我正在尝试使用委托将数据 BACK 传递给之前的 viewController。

有谁知道如何将数据从ViewController B 传回ViewController A？

所以我想将数据从SecondVC 传递到FirstVC，并使用SecondVC 4 地址文本字段中的数据更新自定义表格视图单元格，但由于某种原因，它根本没有更新。

任何帮助都将不胜感激，因为我才刚刚起步，所以尝试了各种各样的事情，但无法让它发挥作用。

FirstVC

import UIKit

class MainVC: UIViewController, UITableViewDelegate, UITableViewDataSource, DataSentDelegate {

    @IBOutlet weak var deliveryAddress: UITableView!

    var customCell: AddressCell = AddressCell()

    override func viewDidLoad() {
        super.viewDidLoad()
        deliveryAddress.delegate = self
        deliveryAddress.dataSource = self
        deliveryAddress.reloadData()
    }

    func userDidEnterData(firstAddress: String, secondAddress: String, cityAddress: String, postcodeAddress: String) {
        customCell.firstLineAddressLbl?.text = firstAddress
        customCell.secondLineAddressLbl?.text = secondAddress
        customCell.cityLineAddressLbl?.text = cityAddress
        customCell.postcodeLineAddressLbl?.text = postcodeAddress
    }

    func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 2
    }



    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
         let cell = tableView.dequeueReusableCell(withIdentifier: "deliveryAddressCell", for: indexPath) as! AddressCell
        cell.updateUI()
        return cell
    }
    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return 165
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "addDeliveryAddressVC" {
            let addDestination:AddingDestinationVC = segue.destination as! AddingDestinationVC
            addDestination.delegate = self
    }


}

}

第二个VC

import UIKit

protocol DataSentDelegate {
    func userDidEnterData(firstAddress: String, secondAddress: String, cityAddress: String, postcodeAddress: String)
}

class AddingDestinationVC: UIViewController {

    @IBOutlet weak var firstLineAddressTextField: UITextField!
    @IBOutlet weak var secondLineAddressTextField: UITextField!
    @IBOutlet weak var cityLineAddressTextField: UITextField!
    @IBOutlet weak var postcodeLineAddressTextField: UITextField!

    var delegate: DataSentDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }
    @IBAction func addBtnWasPressed(_ sender: Any) {
        if delegate != nil {
            if firstLineAddressTextField.text != nil {
                 let firstLineAddress = firstLineAddressTextField.text
                print(firstLineAddress as Any)
                let secondLineAddress = secondLineAddressTextField.text
                let cityLineAddress = secondLineAddressTextField.text
                let postcodeLineAddress = postcodeLineAddressTextField.text
                delegate?.userDidEnterData(firstAddress: firstLineAddress!, secondAddress: secondLineAddress!, cityAddress: cityLineAddress!, postcodeAddress: postcodeLineAddress!)
                navigationController?.popViewController(animated: true)
        }
    }

}
}

自定义单元

import UIKit

class AddressCell: UITableViewCell {

    @IBOutlet weak var firstLineAddressLbl: UILabel!
    @IBOutlet weak var secondLineAddressLbl: UILabel!
    @IBOutlet weak var cityLineAddressLbl: UILabel!
    @IBOutlet weak var postcodeLineAddressLbl: UILabel!
    @IBOutlet weak var numberLbl: UILabel!
    @IBOutlet weak var startBtn: UIButton!
    @IBOutlet weak var distanceLbl: UILabel!
    @IBOutlet weak var metricLbl: UILabel!

    func updateUI() {
        DeliveryDestinations(FirstLineAddress: firstLineAddressLbl.text, SecondLineAddress: secondLineAddressLbl.text, CityLineAddress: cityLineAddressLbl.text, PostCodeLineAddress: postcodeLineAddressLbl.text)
    }

}

模型文件

import Foundation

struct DeliveryDestinations {
    var FirstLineAddress: String?
    var SecondLineAddress: String?
    var CityLineAddress: String?
    var PostcodeLineAddress: String?

    init(FirstLineAddress: String? , SecondLineAddress: String?, CityLineAddress: String?, PostCodeLineAddress: String?) {
        self.FirstLineAddress = FirstLineAddress
        self.SecondLineAddress = SecondLineAddress
        self.CityLineAddress = CityLineAddress
        self.PostcodeLineAddress = PostCodeLineAddress
    }

}

Answer 1

检查以下更正的代码：

MainVC：

import UIKit

class MainVC: UIViewController, UITableViewDelegate, UITableViewDataSource, DataSentDelegate {

    @IBOutlet weak var deliveryAddress: UITableView!

    //Create array which will return your address data
    var addressArr = [DeliveryDestinations]()

    override func viewDidLoad() {
        super.viewDidLoad()
        deliveryAddress.delegate = self
        deliveryAddress.dataSource = self
        deliveryAddress.reloadData()
    }

    //add parameter for created address object
    func userDidEnterData(addressObj: DeliveryDestinations) {

        //append added object into your table array
        self.addressArr.append(addressObj)
        //Reload your tableview once your new object added.
        self.deliveryAddress.reloadData()
    }

    func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

        //change this with array count
        return addressArr.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "deliveryAddressCell", for: indexPath) as! AddressCell

        //get address object from array which you can assign to cell
        let addressObj = addressArr[indexPath.row]
        //assign data from array
        cell.updateUI(addressObj: addressObj)
        return cell
    }

    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return 165
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "addDeliveryAddressVC" {
            let addDestination:AddingDestinationVC = segue.destination as! AddingDestinationVC
            addDestination.delegate = self
        }
    }
}

添加目的地VC：

import UIKit

protocol DataSentDelegate {
    //Replace parameter with DeliveryDestinations
    func userDidEnterData(addressObj: DeliveryDestinations)
}

class AddingDestinationVC: UIViewController {

    @IBOutlet weak var firstLineAddressTextField: UITextField!
    @IBOutlet weak var secondLineAddressTextField: UITextField!
    @IBOutlet weak var cityLineAddressTextField: UITextField!
    @IBOutlet weak var postcodeLineAddressTextField: UITextField!

    var delegate: DataSentDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    @IBAction func addBtnWasPressed(_ sender: Any) {
        if delegate != nil {
            if firstLineAddressTextField.text != nil {

                //Create Model object DeliveryDestinations
                let addressObj = DeliveryDestinations(FirstLineAddress: firstLineAddressTextField.text, SecondLineAddress: secondLineAddressTextField.text, CityLineAddress: cityLineAddressTextField.text, PostCodeLineAddress: postcodeLineAddressTextField.text)
                //add that object to previous view with delegate
                delegate?.userDidEnterData(addressObj: addressObj)
                navigationController?.popViewController(animated: true)
            }
        }
    }
}

地址单元：

class AddressCell: UITableViewCell {

    @IBOutlet weak var firstLineAddressLbl: UILabel!
    @IBOutlet weak var secondLineAddressLbl: UILabel!
    @IBOutlet weak var cityLineAddressLbl: UILabel!
    @IBOutlet weak var postcodeLineAddressLbl: UILabel!
    @IBOutlet weak var numberLbl: UILabel!
    @IBOutlet weak var startBtn: UIButton!
    @IBOutlet weak var distanceLbl: UILabel!
    @IBOutlet weak var metricLbl: UILabel!

    func updateUI(addressObj: DeliveryDestinations) {

        //Drow your cell with values from addressObj
        firstLineAddressLbl.text = addressObj.FirstLineAddress
        secondLineAddressLbl.text = addressObj.SecondLineAddress
        cityLineAddressLbl.text = addressObj.CityLineAddress
        postcodeLineAddressLbl.text = addressObj.PostcodeLineAddress
    }
}

你的结果将是：

here 是您更新后的代码。

Answer 2

维护一个包含数据的数组。

//In your MainVC
var deliveryDestinationDataArray =  [DeliveryDestinations]()

IN委托方法，需要将数据保存到数据源。

func userDidEnterData(firstAddress: String, secondAddress: String, cityAddress: String, postcodeAddress: String) {
    let deliveryDestinationData = DeliveryDestinations(FirstLineAddress: firstAddress, SecondLineAddress: secondAddress, CityLineAddress: cityAddress, PostCodeLineAddress: postcodeAddress)
    deliveryDestinationDataArray.append(deliveryDestinationData)
}

在cellForRowAtIndexPath

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
     let cell = tableView.dequeueReusableCell(withIdentifier: "deliveryAddressCell", for: indexPath) as! AddressCell
   cell.updateUI(deliveryDestinationData:deliveryDestinationDataArray[indexPath.row])
    return cell
}

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    //change count with deliveryDestinationDataArray count
    return deliveryDestinationDataArray.count
}

用数据更新你的单元格

 func updateUI(with dataModel: DeliveryDestinations) {
    firstLineAddressLbl.text = dataModel.FirstLineAddress
    secondLineAddressLbl.text = dataModel.SecondLineAddress
    cityLineAddressLbl.text = dataModel.CityLineAddress
    postcodeLineAddressLbl.text = dataModel.PostcodeLineAddress
}

现在在viewWillAppear中，您需要重新加载tableview。

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    deliveryAddress.reloadData()
}

Answer 3

将您的 FirstVC 替换为以下代码行：

    import UIKit

class MainVC: UIViewController, UITableViewDelegate, UITableViewDataSource, DataSentDelegate {
@IBOutlet weak var deliveryAddress: UITableView!

var dataModels: [DeliveryDestinations] = [DeliveryDestinations]()

override func viewDidLoad() {
    super.viewDidLoad()
    deliveryAddress.delegate = self
    deliveryAddress.dataSource = self
    deliveryAddress.reloadData()
}

func userDidEnterData(firstAddress: String, secondAddress: String, cityAddress: String, postcodeAddress: String) {
    let newEntry: DeliveryDestinations = DeliveryDestinations(FirstLineAddress: firstAddress, SecondLineAddress: secondAddress, CityLineAddress: cityAddress, PostCodeLineAddress: postcodeAddress)
     dataModels.append(newEntry)
     deliveryAddress.reloadData()
}

func numberOfSections(in tableView: UITableView) -> Int {
    return 1
}

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return dataModels.count()
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
     let cell = tableView.dequeueReusableCell(withIdentifier: "deliveryAddressCell", for: indexPath) as! AddressCell
      let dataModel = dataModels[indexPath.row]
    cell.updateUI(with: dataModel)
    return cell
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return 165
}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "addDeliveryAddressVC" {
        let addDestination:AddingDestinationVC = segue.destination as! AddingDestinationVC
        addDestination.delegate = self
}

}

和自定义单元格类：

import UIKit

class AddressCell: UITableViewCell {

    @IBOutlet weak var firstLineAddressLbl: UILabel!
    @IBOutlet weak var secondLineAddressLbl: UILabel!
    @IBOutlet weak var cityLineAddressLbl: UILabel!
    @IBOutlet weak var postcodeLineAddressLbl: UILabel!
    @IBOutlet weak var numberLbl: UILabel!
    @IBOutlet weak var startBtn: UIButton!
    @IBOutlet weak var distanceLbl: UILabel!
    @IBOutlet weak var metricLbl: UILabel!

    func updateUI(with dataModel: DeliveryDestinations) {
        firstLineAddressLbl.text = dataModel.FirstLineAddress
        secondLineAddressLbl.text = dataModel.SecondLineAddress
        cityLineAddressLbl.text = dataModel.CityLineAddress
        postcodeLineAddressLbl.text = dataModel.PostcodeLineAddress
    }

}

此外，您应该以驼峰格式声明您的属性名称。