java我如何复制一个JPanel，它的所有JC组件都具有与原始面板相同的功能？

Question

这是一个gui转换项目。我有一个jcombobox，在相应的jbutton上选择后，它会更新我的jpanel jpTransDetails，执行平移、旋转等操作。现在我要做的是另一个部分，我想有一个完整的jcomboBox和JPanel转换细节的副本，它们具有与此相同的功能。实现这一目标的最佳方式是什么

请注意，为了避免冗长，我只向您展示了部分代码。在其他变换中重复这些部分

更新：我尝试过创建一个基本示例，使用类将新的jpanel添加到jpanel中，但它不起作用

   transNameList = new String[] {"Translation","Rotation","Scaling","Shear","Reflection"};
    jcbTranslations = new JComboBox(transNameList);

    mPane.add(jcbTranslations); //mPane is my main jpanel

    //transDetails JPANEL
    jpTransDetails = new JPanel(null);
    jpTransDetails.setBounds(10,95,320,103);
    jpTransDetails.setOpaque(false);
    Border border = BorderFactory.createLineBorder(Color.white);
    jpTransDetails.setBorder(border);



    //TRANSLATION

    JLabel lblTx = new JLabel("Enter X-Coordinate: ");
    lblTx.setForeground(Color.BLACK);
    lblTx.setFont(new Font("Segoe UI", Font.PLAIN, 12));
    lblTx.setBounds(10,6,150,12);
    lblTx.setToolTipText("Number of units moved along x-axis");

    tTx = new JTextField();
    tTx.setText("0");
    tTx.setColumns(10);
    tTx.setBounds(175, 4, 50, 18);

    JLabel lblTy = new JLabel("Enter Y-Coordinate: ");
    lblTy.setForeground(Color.black);
    lblTy.setFont(new Font("Segoe UI", Font.PLAIN, 12));
    lblTy.setBounds(10, 60, 150, 12);
    lblTy.setToolTipText("Number of units moved along y-axis");



    tTy = new JTextField();
    tTy.setText("0");
    tTy.setColumns(10);
    tTy.setBounds(175, 60, 50, 18);


    bTranslate = new JButton("TRANSLATE");
    bTranslate.setBounds(210,1,110, 25);
    bTranslate.setBackground(Color.black);
    bTranslate.setForeground(Color.WHITE);

    //JPANEL FOR TRANSFORMATION BUTTON
    jpTransBtn =new JPanel(null);
    jpTransBtn.setBounds(10,200,320,28);
    jpTransBtn.setOpaque(false);

    jpTransDetails.setBounds(10,95,320,100);


    //ADDING FOR TRANSLATION 
    jpTransDetails.add(lblTx);
    jpTransDetails.add(tTx);
    jpTransDetails.add(lblTy);
    jpTransDetails.add(tTy);

    //ADDING TRANSLATION BUTTON
    jpTransBtn.add(bTranslate);

    mPane.add(jpTransDetails);
    mPane.add(jpTransBtn);


    //ITEM LISTENER FOR jcbTranslations
    jcbTranslations.addItemListener(new ItemListener()
            {
                public void itemStateChanged(ItemEvent event)
                {
                    if (event.getStateChange() == ItemEvent.SELECTED)
                    {
                        if (jcbTranslations.getSelectedIndex()==0) //TRANSLATION
                        {
                            jpTransDetails.removeAll();
                            jpTransDetails.repaint();

                            jpTransBtn.removeAll();
                            jpTransBtn.repaint();

                            //ADDING FOR TRANSLATION 
                            jpTransDetails.add(lblTx);
                            jpTransDetails.add(tTx);
                            jpTransDetails.add(lblTy);
                            jpTransDetails.add(tTy);

                            //ADDING TRANSLATION BUTTON
                            jpTransBtn.add(bTranslate);


                        }

                        if (jcbTranslations.getSelectedIndex()==1) //ROTATION
                        {
                            jpTransDetails.removeAll();
                            jpTransDetails.repaint();

                            jpTransBtn.removeAll();
                            jpTransBtn.repaint();

                            //ADDING FOR ROTATION
                            jpTransDetails.add(lblRx);
                            jpTransDetails.add(Rotx);
                            jpTransDetails.add(lblRy);
                            jpTransDetails.add(Roty);
                            jpTransDetails.add(lblAngx);
                            jpTransDetails.add(tAngle);


                            //ADDING ROTATION BUTTON
                            jpTransBtn.add(bRotate);


                        }

更新

   public class MainPanelClass extends JFrame   
   {
     public static JPanel selectionpanel;

     MainPanelClass()
     {
       selectionpanel = new JPanel();
       selectionpanel.setPreferredSize(new Dimension(100,200));
       selectionpanel.setBackground(Color.BLUE);
       selectionpanel.add(new CompositeTransformationsPanel());
       add(selectionpanel);

     }

   public static void main(String[] args)
   {
      MainPanelClass mpc = new MainPanelClass();
      mpc.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      mpc.setVisible(true);
      mpc.setSize(300,400);
  }

}

   This is my class extending a jpanel

   public class CompositeTransformationsPanel extends JPanel
   {
        CompositeTransformationsPanel()
        {
          setPreferredSize(new Dimension(20,10));
          setBackground(Color.red);
          setOpaque(false);
        }
   }

Answer 1

实现这一点的最佳方法是创建一个类，该类通过组合扩展JPanel或包含JPanel，其工作是每次都以完全相同的方式创建感兴趣的组件。如果需要两者共享模型，那么可以给这个类一个复制构造函数，它从所有组件中提取模型，并将这些相同的模型放入新创建的JPanel中

其他建议：

• 避免空布局和setBounds，因为这会导致僵化的GUI无法适应不同的操作系统或使用。更好地学习和使用布局管理器
• 尽量将模型代码与程序的非GUI逻辑部分分开，并将视图与GUI部分分开。这将使实现这类事情变得更容易，并使调试和测试代码变得更容易
• 与其手动移除和替换组件，不如使用CardLayout来交换组件，这样更容易、更安全地交换组件

---

在审阅您的代码后，我的建议发生了变化。看起来您想要创建用于对点执行转换的输入表单，并且想要根据JComboBox中的选择更改转换的类型。如果是的话，我的建议是：

• 可能不需要创建多个类似的JPanel和交换JPanel
• 而是使用一个JPanel来完成整个过程
• 给它一个按钮，比如“提交”
• 给那个JButton一个ActionListner
• 在该侦听器中，检查JComboBox的当前状态，即它所选的项
• 根据所选项目进行适当的计算

---

例如：

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import javax.swing.*;
import javax.swing.border.Border;

@SuppressWarnings("serial")
public class PointManipulationPanel extends JPanel {
    private static final int GAP = 5;
    private JComboBox<Transform> transformCombo = new JComboBox<Transform>(Transform.values());
    private JTextField xCoordField = new JTextField("0", 5);
    private JTextField yCoordField = new JTextField("0", 5);

    public PointManipulationPanel() {   
        JPanel coordinatePanel = new JPanel(new GridBagLayout());
        Border outsideBorder = BorderFactory.createLineBorder(Color.WHITE);
        Border insideBorder = BorderFactory.createEmptyBorder(GAP, GAP, GAP, GAP);
        Border border = BorderFactory.createCompoundBorder(outsideBorder, insideBorder);
        coordinatePanel.setBorder(border);
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.gridx = 0;
        gbc.gridy = 0;
        gbc.fill = GridBagConstraints.HORIZONTAL;
        gbc.insets = new Insets(GAP, GAP, GAP, GAP);
        coordinatePanel.add(new JLabel("Enter X-Coordinate: "), gbc);
        gbc.gridy = 1;
        coordinatePanel.add(new JLabel("Enter Y-Coordinate: "), gbc);

        gbc.gridx = 1;
        gbc.gridy = 0;
        coordinatePanel.add(xCoordField, gbc);
        gbc.gridy = 1;
        coordinatePanel.add(yCoordField, gbc);

        JPanel topPane = new JPanel();
        topPane.add(transformCombo);

        JButton submitButton = new JButton("Submit");
        submitButton.addActionListener(e -> submitActionPerformed(e));
        JPanel bottomPanel = new JPanel();
        bottomPanel.add(submitButton);

        setBorder(BorderFactory.createEmptyBorder(GAP, GAP, GAP, GAP));
        setLayout(new BorderLayout(GAP, GAP));
        add(topPane, BorderLayout.PAGE_START);
        add(coordinatePanel);
        add(bottomPanel, BorderLayout.PAGE_END);
    }

    private void submitActionPerformed(ActionEvent e) {
        int x = 0;
        int y = 0;
        try {
            x = Integer.parseInt(xCoordField.getText());
            y = Integer.parseInt(yCoordField.getText());
        } catch (NumberFormatException nfe) {
            // warn user with JOptionPane that data entered no goo
            String message = "Invalid number entry";
            String title = "Invalid Data";
            int messageType = JOptionPane.ERROR_MESSAGE;
            JOptionPane.showMessageDialog(PointManipulationPanel.this, message, title, messageType);

            // exit method
            return;
        }

        // use x and y here in the calculations
        Transform transform = (Transform) transformCombo.getSelectedItem();
        switch (transform) {
        case TRANSLATION:
            // TODO: real code to do calculations goes here
            System.out.printf("Do translation here on x and y: [%d, %d]%n", x, y);
            break;
        case ROTATION:
            // TODO: real code to do calculations goes here
            System.out.printf("Do rotation here on x and y: [%d, %d]%n", x, y);
            break;
        case SCALING:
            // TODO: real code to do calculations goes here
            System.out.printf("Do scaling here on x and y: [%d, %d]%n", x, y);
            break;
        case SHEAR:
            // TODO: real code to do calculations goes here
            System.out.printf("Do shear here on x and y: [%d, %d]%n", x, y);
            break;
        case REFLECTION:
            // TODO: real code to do calculations goes here
            System.out.printf("Do reflection here on x and y: [%d, %d]%n", x, y);
            break;
        default:
            throw new IllegalArgumentException("Unexpected value: " + transform);
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> {
            PointManipulationPanel mainPanel = new PointManipulationPanel();
            JFrame frame = new JFrame("Foo");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.add(mainPanel);
            frame.pack();
            frame.setLocationRelativeTo(null);
            frame.setVisible(true);
        });
    }
}

enum Transform {
    TRANSLATION("Translation"), ROTATION("Rotation"), SCALING("Scaling"), SHEAR("Shear"), REFLECTION("Reflection");

    private String name;

    private Transform(String name) {
        this.name = name;
    }

    String getName() {
        return name;
    }

    @Override
    public String toString() {
        return name;
    }

}