为什么故事板Uaithitview不显示

Question

我是斯威夫特的新手。这是我对UI开发的第一个任务。我已经完美地完成了练习，表观视图如预期的那样出现。该代码如下：

import UIKit

class ViewController: UIViewController {

    @IBOutlet var tableView: UITableView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        tableView.delegate = self
        tableView.dataSource = self
    }


}

extension ViewController: UITableViewDelegate{
    
}

extension ViewController: UITableViewDataSource{
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 3
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "gameScoreCell", for: indexPath)
        cell.textLabel?.text = "hello world"
        cell.detailTextLabel?.text = "score"
        return cell
    }
}

但是，当我遵循同一步骤并尝试将其与我的项目（带有导航控制器）集成在一起时，表视图不会显示。我想念什么吗？

import UIKit

class HightScoreVC: UIViewController {

    @IBOutlet var rankingTable: UITableView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        rankingTable.delegate = self
        rankingTable.dataSource = self
    }


}

extension HightScoreVC: UITableViewDelegate{
    
}

extension HightScoreVC: UITableViewDataSource{
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 3
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "gameScoreCell", for: indexPath)
        cell.textLabel?.text = "hello world"
        cell.detailTextLabel?.text = "123"
        return cell
    }
    
}

Answer 1

我认为您必须在ViewDidload（）中注册您的单元格：

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.
    rankingTable.delegate = self
    rankingTable.dataSource = self
    rankingTable.register(UITableViewCell.self, forCellReuseIdentifier: "gameScoreCell")
}

Answer 2

在与Swift中的TableView合作时要记住的要点。

• 确保桌面的约束得到正确给出。
• 您已经将类连接到身份检查员中的视图控制器。
• 在ViewDidload（）本身中提供代表和数据源，而不是情节板以进行更好的练习。
• 如果要为单元格创建XIB，请确保已注册了TableView的单元格，或者提供原型单元格，请确保提供Dequeuereusablecell（）方法并初始化某些特定类别的单元格。

带有某些原型单元格的表图的简单示例

import UIKit

class UsersListViewController: UIViewController, Storyboarded {

    //MARK: - Variables
    var coordinator: AuthenticationCoordinator?
    var usersList: UsersList?
    
    //MARK: - Outlets
    @IBOutlet weak var tableView: UITableView!
    @IBOutlet weak var progressBar: UIActivityIndicatorView!
    @IBOutlet weak var btnAddUser: UIButton!
    
    //MARK: - UIViewController
    override func viewDidLoad() {
        super.viewDidLoad()
        initializeView()
        getUsersList()
    }
    
    //MARK: - Actions
    @IBAction func addUserAction(_ sender: UIButton) {
        coordinator?.presentAddUser()
    }
    
    //MARK: - File private functions
    fileprivate func initializeView() {
        self.title = "Users list"
        progressBar.startAnimating()
        btnAddUser.layer.masksToBounds = true
        btnAddUser.layer.cornerRadius = btnAddUser.frame.height / 2
        tableView.delegate = self
        tableView.dataSource = self
    }
    
    fileprivate func getUsersList() {
        guard let url = URL(string: ApiUrl.delayResponseURL.rawValue) else { return }
        var request = URLRequest(url: url)
        request.httpMethod = "GET"
        URLSession.shared.dataTask(with: request) { data, response, error in
            guard error == nil else { return }
            guard let data = data else { return }
            guard let response = response as? HTTPURLResponse, (200 ..< 299) ~= response.statusCode else { return }
            do {
                guard let jsonObject = try JSONSerialization.jsonObject(with: data) as? [String: Any] else { return }
                guard let prettyJsonData = try? JSONSerialization.data(withJSONObject: jsonObject, options: .prettyPrinted) else { return }
                guard let responseData = try? JSONDecoder().decode(UsersList.self, from: prettyJsonData) else { return }
                self.usersList = responseData
                DispatchQueue.main.async {
                    self.progressBar.stopAnimating()
                    self.progressBar.alpha = 0
                    self.tableView.reloadData()
                }
            } catch {
                return
            }
        }.resume()
    }
    
}//End of class

//MARK: - UITableViewDelegate
extension UsersListViewController: UITableViewDelegate {
   
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        if let index = usersList?.data[indexPath.row].userID {
            coordinator?.startSingleUserVC(index)
            tableView.deselectRow(at: indexPath, animated: true)
        }
    }
    
}//End of extension

//MARK: - UITableViewDataSource
extension UsersListViewController: UITableViewDataSource {
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        if let cell = tableView.dequeueReusableCell(withIdentifier: "singleUserCell") as? SingleUserTableViewCell {
            if let url = URL(string: usersList?.data[indexPath.row].avatar ?? "") {
                DispatchQueue.global().async {
                    guard let data = try? Data(contentsOf: url) else { return }
                    val currentUser = self.usersList?.data[indexPath.row]
                    DispatchQueue.main.async {
                        cell.initCell(data, currentUser.firstName, currentUser.email)
                    }
                }
            }
            return cell
        }
        return UITableViewCell()
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return usersList?.data.count ?? 1
    }
    
}//End of extension