如何使用ActionListener将JPanel表单添加到JFrame表单？

Question

This is my first time on stack overflow, and I really have found it helpful for pretty much every issue I have had. I finally just needed to get an account since I finally have a question that I cannot find an answer to. I am using Netbeans 7.3 now, and I am using the GUI editor for the first time. I needed the precise positioning so I couldn't do the GUI's manually. My issue is that I have a JFrame form with a JPanel form added to it (I just drug it onto the window and it seemed to work fine) and i want to add a second JPanel as well, but whether i do it or not is based upon a jcombobox selection in the first JPanel. I started by adding an action listener to the jcombobox in the first JFrame. My plan was to add the second JPanel from within that action performed method tied to that jcombobox, but i don't know how to add it. I apologize if i am not making much since. I am a beginner. Also from reading my code you might find out what I'm trying to do, but to be honest i can't even get there until i figure out the gui. Perhaps some code might help:

This is the JFrame Code:

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package geometry.program;

import javax.swing.JPanel;

/**
 *
 * @author maxwellparker
 */
public class Main extends javax.swing.JFrame {

    /**
     * Creates new form Main
     */
    public Main() {
        super("Geometry Sucks");
        initComponents();
        this.setLocationRelativeTo(null);
    }

    public void addPanel(JPanel j){
        //i was going to call this method from the first jpanel on this JFrame already to add the second one.
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        rP1 = new geometry.program.RP();
        control1 = new geometry.program.Control();
        rP2 = new geometry.program.RP();
        rP3 = new geometry.program.RP();
        control2 = new geometry.program.Control();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        org.jdesktop.layout.GroupLayout layout = new org.jdesktop.layout.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(layout.createSequentialGroup()
                .addContainerGap()
                .add(control2, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(92, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(layout.createSequentialGroup()
                .addContainerGap()
                .add(control2, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(189, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>                        

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new Main().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify                     
    private geometry.program.Control control1;
    private geometry.program.Control control2;
    private geometry.program.RP rP1;
    private geometry.program.RP rP2;
    private geometry.program.RP rP3;
    // End of variables declaration                   
}

This is the JPanel 1 code:

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package geometry.program;

/**
 *
 * @author maxwellparker
 */
public class Control extends javax.swing.JPanel {

    /**
     * Creates new form Control
     */
    public Control() {
        initComponents();
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        Mode = new javax.swing.JLabel();
        ModeComboBox = new javax.swing.JComboBox();
        Var = new javax.swing.JLabel();
        VarField = new javax.swing.JTextField();
        Val = new javax.swing.JLabel();
        ValField = new javax.swing.JTextField();
        CustomVar = new javax.swing.JLabel();

        Mode.setText("Mode:");

        ModeComboBox.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Regular Polygons", "Second", "Third", "Fourth" }));
        ModeComboBox.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                ModeComboBoxActionPerformed(evt);
            }
        });

        Var.setText("Variable:");

        Val.setText("Value:");

        CustomVar.setText("Custom Variable (Optional):");

        org.jdesktop.layout.GroupLayout layout = new org.jdesktop.layout.GroupLayout(this);
        this.setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(layout.createSequentialGroup()
                .add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
                    .add(CustomVar)
                    .add(layout.createSequentialGroup()
                        .add(Var)
                        .addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED)
                        .add(VarField, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, 30, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
                        .addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED)
                        .add(Val)
                        .addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED)
                        .add(ValField, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, 59, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE))
                    .add(layout.createSequentialGroup()
                        .addContainerGap()
                        .add(Mode)
                        .addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED)
                        .add(ModeComboBox, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)))
                .addContainerGap(org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(layout.createSequentialGroup()
                .addContainerGap()
                .add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.BASELINE)
                    .add(Mode)
                    .add(ModeComboBox, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE))
                .add(18, 18, 18)
                .add(CustomVar)
                .add(18, 18, 18)
                .add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.BASELINE)
                    .add(Var)
                    .add(Val)
                    .add(VarField, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
                    .add(ValField, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE))
                .addContainerGap(org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
    }// </editor-fold>                        

    private void ModeComboBoxActionPerformed(java.awt.event.ActionEvent evt) {                                             
        if(ModeComboBox.getSelectedIndex()==0){
            //run option 1
            System.out.println("Add corresponding option Panel To JFrame.");
        }else if(ModeComboBox.getSelectedIndex()==1){
            System.out.println("Add corresponding option Panel To JFrame.");
        }else if(ModeComboBox.getSelectedIndex()==2){
            System.out.println("Add corresponding option Panel To JFrame.");
        }else if(ModeComboBox.getSelectedIndex()==3){
            System.out.println("Add corresponding option Panel To JFrame.");
        }
    }                                            

    // Variables declaration - do not modify                     
    private javax.swing.JLabel CustomVar;
    private javax.swing.JLabel Mode;
    private javax.swing.JComboBox ModeComboBox;
    private javax.swing.JLabel Val;
    private javax.swing.JTextField ValField;
    private javax.swing.JLabel Var;
    private javax.swing.JTextField VarField;
    // End of variables declaration                   
}

And this is the Second JPanel code (the one i want to add to the JFrame based upon the combo box in JPanel 1).

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package geometry.program;

/**
 *
 * @author maxwellparker
 */
public class Control extends javax.swing.JPanel {

    /**
     * Creates new form Control
     */
    public Control() {
        initComponents();
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        Mode = new javax.swing.JLabel();
        ModeComboBox = new javax.swing.JComboBox();
        Var = new javax.swing.JLabel();
        VarField = new javax.swing.JTextField();
        Val = new javax.swing.JLabel();
        ValField = new javax.swing.JTextField();
        CustomVar = new javax.swing.JLabel();

        Mode.setText("Mode:");

        ModeComboBox.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Regular Polygons", "Second", "Third", "Fourth" }));
        ModeComboBox.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                ModeComboBoxActionPerformed(evt);
            }
        });

        Var.setText("Variable:");

        Val.setText("Value:");

        CustomVar.setText("Custom Variable (Optional):");

        org.jdesktop.layout.GroupLayout layout = new org.jdesktop.layout.GroupLayout(this);
        this.setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(layout.createSequentialGroup()
                .add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
                    .add(CustomVar)
                    .add(layout.createSequentialGroup()
                        .add(Var)
                        .addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED)
                        .add(VarField, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, 30, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
                        .addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED)
                        .add(Val)
                        .addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED)
                        .add(ValField, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, 59, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE))
                    .add(layout.createSequentialGroup()
                        .addContainerGap()
                        .add(Mode)
                        .addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED)
                        .add(ModeComboBox, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)))
                .addContainerGap(org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(layout.createSequentialGroup()
                .addContainerGap()
                .add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.BASELINE)
                    .add(Mode)
                    .add(ModeComboBox, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE))
                .add(18, 18, 18)
                .add(CustomVar)
                .add(18, 18, 18)
                .add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.BASELINE)
                    .add(Var)
                    .add(Val)
                    .add(VarField, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
                    .add(ValField, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE))
                .addContainerGap(org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
    }// </editor-fold>                        

    private void ModeComboBoxActionPerformed(java.awt.event.ActionEvent evt) {                                             
        if(ModeComboBox.getSelectedIndex()==0){
            //run option 1
            System.out.println("Add corresponding option Panel To JFrame.");
        }else if(ModeComboBox.getSelectedIndex()==1){
            System.out.println("Add corresponding option Panel To JFrame.");
        }else if(ModeComboBox.getSelectedIndex()==2){
            System.out.println("Add corresponding option Panel To JFrame.");
        }else if(ModeComboBox.getSelectedIndex()==3){
            System.out.println("Add corresponding option Panel To JFrame.");
        }
    }                                            

    // Variables declaration - do not modify                     
    private javax.swing.JLabel CustomVar;
    private javax.swing.JLabel Mode;
    private javax.swing.JComboBox ModeComboBox;
    private javax.swing.JLabel Val;
    private javax.swing.JTextField ValField;
    private javax.swing.JLabel Var;
    private javax.swing.JTextField VarField;
    // End of variables declaration                   
}

Thank you very much for the help.

Answer 1

Hej, i made a very simple example for you. I created the "GUI" programmtically.

On the JFrame i placed one JPanel , called firstPanel , on this Panel you'll find a JComboBox and if you choose the option add new JPanel , another JPanel will be added to the JFrame , if you choose hide JPanel , the secondPanel will be removed, only for demonstration of the actionPerformed() method.

MainFrame class

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class MainFrame extends JFrame {

    JPanel firstPanel;
    JComboBox<String> comboBox;
    String[] items = {"choose an option", "hide JPanel", "add new JPanel"};


    public MainFrame() {

    }

    public void createAndShowGui() {

        initComponents();
        this.setTitle("Add new JPanel with ComboBox");
        this.setSize(new Dimension(1024, 768));
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.getContentPane().add(firstPanel, BorderLayout.NORTH);
        this.setVisible(true);
    }

    private void initComponents() {
        firstPanel = new JPanel(new GridLayout(3, 1));
        firstPanel.add(new JLabel("First Panel"));
        comboBox = new JComboBox<>(items);
        JPanel panel = new JPanel();
        comboBox.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                if(comboBox.getSelectedItem().toString().equalsIgnoreCase("add new JPanel")) {

                    panel.setBackground(Color.ORANGE);
                    panel.setSize(new Dimension(500, 300));

                    getContentPane().add(panel, BorderLayout.SOUTH);
                }

                if(comboBox.getSelectedItem().toString().equalsIgnoreCase("hide JPanel")) {
                    getContentPane().remove(panel);
                }
            }
        });

        firstPanel.add(comboBox);
    }
}

Start the App

import de.professional_webworkx.blog.swingjpanel.frame.MainFrame;
import java.awt.EventQueue;

public class SwingJPanel {

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                MainFrame mainFrame = new MainFrame();
                mainFrame.createAndShowGui();
            }
        });
    }

}

I think this will be the part of your interest:

comboBox.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                if(comboBox.getSelectedItem().toString().equalsIgnoreCase("add new JPanel")) {

                    panel.setBackground(Color.ORANGE);
                    panel.setSize(new Dimension(500, 300));

                    getContentPane().add(panel, BorderLayout.SOUTH);
                }

                if(comboBox.getSelectedItem().toString().equalsIgnoreCase("hide JPanel")) {
                    getContentPane().remove(panel);
                }
            }
        });

Patrick.