java - JPanels 未添加到 JTabbedPane

Question

为了我的家庭作业加分，我创建了一个 JTabbedPane 并添加了两个 Jpanel。我觉得我已经很接近了，但它仍然无法编译。当我运行它时，两个 JPanel 都会打开，但 JTabbedPane 不会。我收到很多未知来源错误。我怀疑此时我的问题出在 JPanel 本身，因为它们开始是 JFrames，而我已经尝试(我认为未成功)将 JFrames 转换为 JPanel。

JTabbedPaneAssignment 应该创建 JTabbedPane 并在两个 Pane 中填充一个选项卡上的应用程序 DayGui 和另一个选项卡上的 OfficeAreaCalculator。我在这里只包含 JTabbedPaneAssignment 和 DayGui 类。如果它的代码太多，我深表歉意，我已经删掉了很多我认为无关的东西，但可能还是太多了。

这里是调用类 JTabbedPaneAssignment

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

public class JTabbedPaneAssignment extends JPanel
{
    public JTabbedPaneAssignment()
    {
        //super(new GridLayout(1, 1));

        JTabbedPane tabbedPane = new JTabbedPane();
        DayGui pnlDay = new DayGui();
        OfficeAreaCalculator  pnlOffice = new OfficeAreaCalculator ();
        this.add(tabbedPane);

        JPanel panel1 = new JPanel();
        JPanel panel2 = new JPanel();
        tabbedPane.add(panel1,"First panel");
        tabbedPane.add(panel2,"Second panel");


        //JComponent panel1 = makeTextPanel("Pane #1");
        panel1.setPreferredSize(new Dimension(300, 150));
        tabbedPane.addTab("DayGui", panel1);
        tabbedPane.setMnemonicAt(0, KeyEvent.VK_1);

        //JComponent panel2 = makeTextPanel("Pane #2");
        panel2.setPreferredSize(new Dimension(410, 50));
        tabbedPane.addTab("OfficeAreaCalculator", panel2);
        tabbedPane.setMnemonicAt(1, KeyEvent.VK_2);
        add(tabbedPane);
    }

    protected JComponent makeTextPanel(String text)
    {
        JPanel panel = new JPanel(false);
        JLabel filler = new JLabel(text);
        filler.setHorizontalAlignment(JLabel.CENTER);
        panel.setLayout(new GridLayout(1, 1));
        panel.add(filler);
        return panel;
    }

    // Create JTabbedPane
    private static void createAndShowGUI()
    {
        // Create and set up the window.
        JFrame frame = new JFrame("JTabbedPane");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(new JTabbedPaneAssignment(), BorderLayout.CENTER);
        JTabbedPane DayGui = new JTabbedPane();
        JTabbedPane OfficeAreaCalculator = new JTabbedPane();
        frame.pack();
        frame.setVisible(true);
    }


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

这是 DayGui 类。它最初是一个 JFrame，但我试图将它转换为 JPanel。我认为我的问题出在这部分代码中，但我不知道

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;

//public class DayGui extends JPanel
public class DayGui extends JPanel
{
    private JPanel dayPanel;
    private JButton cmdGood;
    private JButton cmdBad;

    public DayGui()
    {
        //dayPanel = new JPanel("Messages");

        cmdGood = new JButton("Good");
        cmdBad = new JButton("Bad");

        Container c = dayPanel.getRootPane();
        c.setLayout(new FlowLayout());

        c.add(cmdGood);
        c.add(cmdBad);

        dayPanel.setSize(300, 150);

        ButtonsHandler bhandler = new ButtonsHandler();
        cmdGood.addActionListener(bhandler);
        cmdBad.addActionListener(bhandler);

        dayPanel.setVisible(true);
        dayPanel.getRootPane().setBackground(Color.CYAN);

    }

    class ButtonsHandler implements ActionListener
    {
        public void actionPerformed(ActionEvent e)
        {
            if (e.getSource() == cmdGood)
                JOptionPane.showMessageDialog(null, "Today is a good day!",
                        "Event Handler Message",
                        JOptionPane.INFORMATION_MESSAGE);
            if (e.getSource() == cmdBad)
                JOptionPane.showMessageDialog(null, "Today is a bad day!",
                        "Event Handler Message",
                        JOptionPane.INFORMATION_MESSAGE);
        }
    }

}

Answer 1

你的问题一直很模棱两可，而且你发布的代码比这里的任何人有时间浏览的都多。

我制作了一个非常小但有效的 JTabbedPane 示例，让您了解最小的工作量以使其正常工作。

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTabbedPane;

public class JTabbedPaneExample extends JFrame{

    public JTabbedPaneExample(String title){
        super(title);
        setSize(800,600);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
        
        JTabbedPane tabbedPane = new JTabbedPane();
        
        JPanel panelOne = new JPanel();
        JPanel panelTwo = new JPanel();
        tabbedPane.add(panelOne,"First panel");
        tabbedPane.add(panelTwo,"Second panel");
        
        add(tabbedPane);
    }
    
    
    public static void main(String[] args){
        
        new JTabbedPaneExample("JTP Example").setVisible(true);
        
    }
} 

然后运行，这段代码看起来像:

如果您在代码中重复相同的过程，但仍然有错误，则问题不在于您的 JTabbedPane，而在于其他方面。