使用带有委托协议的 Tableview 将数据从视图控制器 B 传递到视图控制器 A

Question

我正在研究如何将数据从一个子视图控制器传递到父视图控制器。它们都包含 tableViews。我想选择视图控制器 B 中的单元格并点击一个按钮并将该数据发送回视图控制器 A。我正在使用委托和协议。我的问题是我不确定在 IBAction 中使用什么来让按钮显示在父视图控制器中。

我的视图控制器 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")
        }
    }
}

查看控制器 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)
        }
        
    }
}

控制器的图像：

Answer 1

UITableView 有一个属性indexPathForSelectedRow，可以让您询问选择了哪一行。

在您的按钮操作中，检查该属性。如果为 nil，则不选择任何单元格。如果不为零，请使用 indexPath 从模型中获取数据并将其传递回第一个视图控制器。