java - CardLayout，来自单独类的面板未显示

Question

我正在为一个相当简单的棋盘游戏制作我的第一个 GUI。除了游戏 View 之外，我还需要主菜单和其他一些 View 。不幸的是，我的 GUI 看起来比早上更难看，因为整个菜单结构都在一个类中。我使用卡片布局在不同 View 之间切换，所以我想我可以将这些 View 分成不同的类。可悲的是，这就是我遇到问题的地方。我得到的只是一个空白窗口。

经过四个小时的研究，我还没能解决我的问题，所以我问你们，你们知道我的代码有什么问题吗？即使很困难，我认为我已经排除了明显的问题(没有使用卡片布局将面板添加到我的面板中，没有设置布局等)，我仍然认为问题一定是非常简单的。但我发现没有任何帮助。

对于企业来说，这是我的“基本 GUI”

package teekkariloikka.gui;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;


public class TLGui extends JFrame {

    private static final long serialVersionUID = 1L;

    private static final int WIDTH = 1000;
    private static final int HEIGHT = 800;

    private static final String MAINMENU = "mainmenu";
    private static final String GAME = "game";

    private JPanel basePanel;

    private GameViewPanel gameViewPanel;
    private MainMenuPanel mainMenuPanel;

    JFrame frame = new JFrame();

    //Layout
    private CardLayout cardL = new CardLayout();

    public TLGui(){

        //Frame stuff
        frame.setTitle("Teekkariloikka");
        frame.setSize(WIDTH, HEIGHT);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        frame.setResizable(false);      

        //This is the panel where I add the ohter panels for menu and game
        basePanel = new JPanel();
        basePanel.setLayout(cardL);

        //Creating the panels I want to add. Excuse the confusing naming.
        gameViewPanel = new GameViewPanel(); 
        mainMenuPanel = new MainMenuPanel();

        //Adding the panels to the basePanel
        basePanel.add(mainMenuPanel, MAINMENU);
        basePanel.add(gameViewPanel, GAME);
        cardL.show(basePanel, MAINMENU);        

        //ADDING basePanel to the frame
        frame.add(basePanel);

        //Action listeners for buttons. Take a look at the classes.
        mainMenuPanel.setNewGameButtonListener(new ActionListener(){
            @Override
            public void actionPerformed(ActionEvent e){
                cardL.show(basePanel, GAME);
            }
        });

        gameViewPanel.setMainMenuButtonListener(new ActionListener(){
            @Override
            public void actionPerformed(ActionEvent e){{
                cardL.show(basePanel, MAINMENU);
            }
        }); 
    }

    public static void main(String[] args){
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run(){
                new TLGui();
            }
        }); 
    }
}

然后是我的 MainMenuPanel 类。这是一项正在进行的工作，但至少应该显示按钮。我尽了最大努力翻译我用芬兰语(我的母语)写的所有内容，我真的希望我不会对我的代码视而不见，以至于忘记了一些东西。

package teekkariloikka.gui;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class MainMenuPanel extends JPanel{

    private static final long serialVersionUID = 1L;

    //Buttons
    private JPanel panel;
    private JButton newGameButton;
    private JButton quitButton;

    //Font
    Font menuFont = new Font("Arial", Font.BOLD, 24);
    //Layout
    private GridBagLayout menuLayout = new GridBagLayout();
    private GridBagConstraints c1 = new GridBagConstraints();

    public MainMenuPanel(){

        panel = new JPanel();

        //For testing //TODO remove
        panel.setBackground(Color.BLACK);

        newGameButton = new JButton("New Game");
        quitButton = new JButton("Quit");

        //New Game -button
        newGameButton.setPreferredSize(new Dimension(200, 100));
        newGameButton.setFont(menuFont);

        //Quit-button
        quitButton.setPreferredSize(new Dimension(200, 100));
        quitButton.setFont(menuFont);

        panel.setLayout(menuLayout);
        c1.insets = new Insets(10, 10, 10, 10);
        c1.gridx = 0;
        c1.gridy = 1;
        panel.add(newGameButton, c1);
        c1.gridx = 0;
        c1.gridy = 2;
        panel.add(quitButton, c1);
    }

    //Idea: http://stackoverflow.com/questions/19104014/add-an-actionlistener-to-a-jbutton-from-another-class
    public void setNewGameButtonListener(ActionListener listener){
        newGameButton.addActionListener(listener);
    }

    public void setQuitButtonListener(ActionListener listener){
        quitButton.addActionListener(listener);
    }
}

还有 GameViewPanel 类。也在进行中，但像上一个类一样，这看起来应该很好。

package teekkariloikka.gui;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;

public class GameViewPanel extends JPanel{

    private static final long serialVersionUID = 1L;

    private JButton lopetaButton;
    private JButton tallennaButton;
    private JButton menuButton;

    BorderLayout bordL = new BorderLayout();    

    public GameViewPanel(){

        JPanel gameViewPanel = new JPanel();

        gameViewPanel.setLayout(bordL);
        gameViewPanel.setBorder(new EmptyBorder(10, 10, 10, 10)); 

        //Creating toolbar
        JToolBar toolbar = new JToolBar();
        toolbar.setFloatable(false);

        gameViewPanel.setLayout(bordL);
        gameViewPanel.setBorder(new EmptyBorder(10, 10, 10, 10)); 
        gameViewPanel.add(toolbar, BorderLayout.PAGE_START);        

        //Buttons
        lopetaButton = new JButton("Lopeta");
        menuButton = new JButton("Päävalikko");
        tallennaButton = new JButton("Tallenna");

        //Adding buttons to game view toolbar
        toolbar.add(lopetaButton); //TODO Add functionality!
        toolbar.add(tallennaButton); //TODO Add functionality!
        toolbar.add(menuButton); //TODO Add functionality!
    }

    public void setMainMenuButtonListener(ActionListener listener){
        menuButton.addActionListener(listener);
    }
}

我希望有人能指出我所犯的错误 - 无论我感觉多么愚蠢。

此外，任何其他反馈都将受到高度赞赏。正如我所说，这是我第一次编写 GUI，我必须说我时不时感到很失落。

Answer 1

 cardL.show(basePanel, "2");

面板的名称不是“2”。

您定义变量MAINMENU和GAME来表示每个面板的名称。