更改 TableViewCell 上 Label 的文本

Question

我有第一个视图控制器（FirstView Controller），它显示了两个 TextFields 和一个 TableView，其中包括 TableViewCell 和 Label。而且我有第二个视图控制器（TypeViewController），它还包括 TableView 和包含一个标签的 TableViewCell。

在 FirstViewController 上选择带有文本的 TableViewCell Choose -> 继续查看 TypeViewController

在 TypeViewController 上选择 TableViewCell（在 TypeViewController 上，我有单元格列表，可以动态加载）-> 返回 FirstViewController，而不是文本 Choose 显示在 TypeViewController 上选择的文本。

如何将 FirstViewController 上 TableViewCell 上的 Label 文本更改为 TypeViewController 中的文本？

第一个视图控制器

import UIKit

class FirstViewController: UIViewController, UITextFieldDelegate, UITableViewDataSource, UITableViewDelegate {

    var animalTypeName: String?;

    var selectedTypeId: UInt?;
    var selectedTypeName: String?;

    override func viewDidLoad() {
        super.viewDidLoad();
    }

    // MARK: TableView && TableViewCell Methods
    // Row display.
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 1;
    }

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

        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as! FirstTableViewCell;
        animalTypeName = "Choose";
        cell.typeName.text = animalTypeName;

        return cell;
    }

    //MARK: - Navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

        super.prepare(for: segue, sender: sender)

        switch(segue.identifier ?? "") {
            case "ShowType":
                guard segue.destination is TypeViewController else {
                fatalError("Unexpected destination: \(segue.destination)");
                }
            default:
                fatalError("Unexpected Segue Identifier; \(String(describing: segue.identifier))");
        }
    }

    //MARK: Actions
    @IBAction func unwindToCreateMedicamentController(sender: UIStoryboardSegue) {
        if let typeViewController = sender.source as? TypeViewController, let type = typeViewController.type {

            selectedTypeName = type.name;
            selectedTypeId = type.animalTypeId;
            animalTypeName = selectedTypeName;
        }
    }
}

TypeViewController

import UIKit

 class TypeViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {

    @IBOutlet weak var tableView: UITableView!

    var typeList: [AnimalType]?;
    var type: AnimalType?;
    let typeController = AnimalTypeController();

    override func viewDidLoad() {
        super.viewDidLoad();
        // Call method to get array of AnimalType items.
        getArrayOfTypeItems();
    }

    //MARK: - Table view data source
    func numberOfSections(in tableView: UITableView) -> Int {
        return 1;
    }

    // Row display.
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return typeList?.count ?? 0;
    }

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

    // Table view cells are reused and should be dequeued using a cell identifier.
    let cellIdentifier = "TypeTVCell";

    guard let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier, for: indexPath) as? TypeTableViewCell  else {
        fatalError("The dequeued cell is not an instance of TypeTVCell.");
    }

        let typeItem = typeList?[indexPath.row];
        cell.nameOfType.text = typeItem!.name;

        return cell;
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

        super.prepare(for: segue, sender: sender)

        switch(segue.identifier ?? "") {
        case "ChooseType":
            guard segue.destination is CreateMedicamentController else {
                fatalError("Unexpected destination: \(segue.destination)");
            }

            guard let selectedTypeCell = sender as? TypeTableViewCell else {
                fatalError("Unexpected sender: \(String(describing: sender))");
            }

            guard let indexPath = tableView.indexPath(for: selectedTypeCell) else {
                fatalError("The selected cell is not being displayed by the table");
        }
            let selectedType = typeList?[indexPath.row];
            type = selectedType;

        default:
            fatalError("Unexpected Segue Identifier; \(String(describing: segue.identifier))")
        }
    }
}

Answer 1

在viewDidLoad方法s中需要添加以下代码：

tableView.dataSource = self
tableView.delegate = self

Answer 2

class FirstViewController: UIViewController, UITextFieldDelegate, UITableViewDataSource, UITableViewDelegate {

    var animalTypeName: String?;

    var selectedTypeId: UInt?;
    var selectedTypeName: String?;

    @IBOutlet weak var tableView: UITableView!

    override func viewDidLoad() {
        super.viewDidLoad();
        animalTypeName = "Choose";
    }

    // MARK: TableView && TableViewCell Methods
    // Row display.
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 1;
    }

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

        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as! FirstTableViewCell;
        cell.typeName.text = animalTypeName;

        return cell;
    }

    //MARK: - Navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

        super.prepare(for: segue, sender: sender)

        switch(segue.identifier ?? "") {
            case "ShowType":
                guard segue.destination is TypeViewController else {
                    fatalError("Unexpected destination: \(segue.destination)");
                }
            default:
                fatalError("Unexpected Segue Identifier; \(String(describing: segue.identifier))");
        }
    }

    //MARK: Actions
    @IBAction func unwindToCreateMedicamentController(sender: UIStoryboardSegue) {
        if let typeViewController = sender.source as? TypeViewController, let type = typeViewController.type {

            selectedTypeName = type.name;
            selectedTypeId = type.animalTypeId;
            animalTypeName = selectedTypeName;

            tableView.reloadData();
        }
    }
}

1. 将animalTypeName = "Choose"; 移至viewDidLoad。
2. 在FirstViewController 中添加@IBOutlet weak var tableView: UITableView!
3. 在unwindToCreateMedicamentController(sender: UIStoryboardSegue) 中添加tableView.reloadData()