ios - Passing Data From View Controller B using a button to View Contoller A with Tableview with delegate- protocol

Question

I am looking how to pass data from one child View controller to the parent view controller. They both contain tableViews. I want to select the cell in View Controller B and hit a button and send that data back to View controller A. I am using Delegates and Protocol. My issue is that i am not sure what to use in the IBAction for the button to make it appear in the parent view controller.

My View Controller A:

class ViewController: UIViewController, DataEnteredDelegate, UITableViewDelegate, UITableViewDataSource, DataSelectedDelegate {

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

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }
    
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "showSecondViewController", let secondViewController = segue.destination as? SecondViewController  {
            secondViewController.delegate = self
        } else {
            if segue.identifier == "showThirdViewController", let thirdViewController = segue.destination as? ThirdViewController {
                thirdViewController.selectedDelegate = self
            }
            
        }
    }
    

    // required method of our custom DataEnteredDelegate protocol
    func userDidEnterInformation(info: String) {
        navigationController?.popViewController(animated: true)
        self.tableArrayHeader.append(info)
        self.tableView.reloadData()
        
    }
    
    func userDidSelectInformation(selection: String) {
        navigationController?.popViewController(animated: true)
        self.tableArrayHeader.append(selection)
        self.tableView.reloadData()
    }
    
    @IBAction func addingButton(_ sender: Any) {
        tableViewArray.insert("new Cell", at: 0)
        tableView.insertRows(at: [IndexPath(row: 0, section: 0)], with: .right)
       
    }
    
    func numberOfSections(in tableView: UITableView) -> Int {
        return tableArrayHeader.count
    }
    
    func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        return tableArrayHeader[section]
    }

    
    func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        let cell = tableView.dequeueReusableCell(withIdentifier: "headerCell") as? CustomHeaderTableViewCell
        cell?.headerLabel?.text = tableArrayHeader[section]
        cell?.backgroundColor = UIColor.lightGray
        return cell
    }
    
    func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
        return 55
    }
    
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return tableViewArray.count
    }

    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! FirstTableViewCell
        cell.label.text = tableViewArray[indexPath.row]
        return cell
    }
    
    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return 55
    }
    
//    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
//        tableView.deselectRow(at: indexPath, animated: true)
//    }
    
    func tableView(_ tableView: UITableView, editingStyleForRowAt indexPath: IndexPath) -> UITableViewCell.EditingStyle {
        return .delete
    }
    
    func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
        if editingStyle == .delete {
            tableView.beginUpdates()
            tableViewArray.remove(at: indexPath.row)
            tableView.deleteRows(at: [indexPath], with: .bottom)
            tableView.endUpdates()
        } else{
            print("there are no cells to delete")
        }
    }
}

View Controller B:

protocol DataSelectedDelegate {
    func userDidSelectInformation(selection: String)
}

class ThirdViewController: ViewController {

    var selectedDelegate: DataSelectedDelegate?
    
    struct Objects {

        var sectionName : String!
        var sectionObjects : [String]!
    }
    
    var objectArray = [Objects]()


    var tableArray = ["this","is","test","date"]
    var names = ["Vegetables": ["Tomato", "Potato", "Lettuce"], "Fruits": ["Apple", "Banana"]]
    
    //var objectArray = [String]()
    var selectionArray : [String] = []
    var selectedIndexPath = [IndexPath]()
    var selectedIndex = -1
    
    @IBOutlet weak var thirdTable: UITableView!
    

    override func viewDidLoad() {
        super.viewDidLoad()
        for (key, value) in names {
        print("(key) -> (value)")
        objectArray.append(Objects(sectionName: key, sectionObjects: value))
        }
    }
    
    
    @IBAction func sendDataFromTableToTable(_ sender: Any) {
        selectedDelegate?.userDidSelectInformation(selection: // This is where i am unsure of what to put so that the selected cell data will go back when the button is pressed "" )
    }
    
//    @IBAction func sendDataFromRowToTable(_ sender: Any) {
//        selectedDelegate?.userDidSelectInformation(selection: selectedIndexPath.description ?? "" )
//    }

    override func numberOfSections(in tableView: UITableView) -> Int {
        return objectArray.count
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return objectArray[section].sectionObjects.count
        //return tableArray.count
    }

    override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {

        return objectArray[section].sectionName

    }
    
    override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return 55
    }
    
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        
        let cell = tableView.dequeueReusableCell(withIdentifier: "thirdCell", for: indexPath)
        
        cell.textLabel?.text = objectArray[indexPath.section].sectionObjects[indexPath.row]
        
        cell.textLabel?.text = tableArray[indexPath.row]
        
        if selectedIndexPath.contains(indexPath) {
            cell.accessoryType = .checkmark
        } else {
            cell.accessoryType = .none
        }
        
        return cell
    }
    
     func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
      
        if selectedIndexPath.contains(indexPath) {
            selectedIndexPath.removeAll() {
                (selectedIndexPath) -> Bool in
                selectedIndexPath == indexPath
            }
            thirdTable.reloadRows(at: [indexPath], with: .fade)
            print(selectedIndexPath.description)
        } else {
            selectedIndexPath.append(indexPath)
            thirdTable.reloadRows(at: [indexPath], with: .fade)
        }
        
        selectionArray.append(tableArray[indexPath.row])
        print(selectionArray)
    }

    func tableView(_ tableView: UITableView, didDeselectRowAt indexPath: IndexPath) {
        if let index = selectionArray.firstIndex(of: tableArray[indexPath.row]) {
            selectionArray.remove(at: index)
            print(tableArray)
        }
        
    }
}

Images of the controllers:

question from:https://stackoverflow.com/questions/66052032/passing-data-from-view-controller-b-using-a-button-to-view-contoller-a-with-tabl

Answer 1

UITableView has a property indexPathForSelectedRow that lets you ask which row is selected.

In your button action, check that property. If it's nil, no cell is selected. If it is not nil, use the indexPath to fetch the data from your model and pass it back to the first view controller.