How to show/hide JPanels in a JFrame?

Question

The application I am developing is a game. What I want to do is have JPanels that appear in the JFrame, like a text or message window, and then disappear when they are no longer used. I have designed these JPanels in Netbeans as external classes and want to be able to call them in an actionPerformed() method. JOptionPanes or other popup dialogs are not an option because they take the focus away from the game. I also saw someone suggest a CardLayout in a similar question. This is not what I want because I am not just trying to swap the panes. They should go away when the program tells them to. How would I do this, say by binding it to a JButton Action?

Answer 1

You can hide a JPanel by calling setVisible(false). For example:

public static void main(String args[]){
    JFrame f = new JFrame();
    f.setLayout(new BorderLayout());
    final JPanel p = new JPanel();
    p.add(new JLabel("A Panel"));
    f.add(p, BorderLayout.CENTER);

    //create a button which will hide the panel when clicked.
    JButton b = new JButton("HIDE");
    b.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
                p.setVisible(false);
        }
    });

    f.add(b,BorderLayout.SOUTH);
    f.pack();
    f.setVisible(true);
}

Answer 2

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

/*
 * Style1.java
 *
 * Created on May 5, 2011, 6:31:16 AM
 */
package Test;

import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JOptionPane;

/**
 *
 * @author Sameera
 */
public class Style2 extends javax.swing.JFrame {

    /** Creates new form Style1 */
    public Style2() {
        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() {

        jPanel1 = new javax.swing.JPanel();
        cmd_SH = new javax.swing.JButton();
        pnl_2 = new javax.swing.JPanel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jPanel1.setBorder(javax.swing.BorderFactory.createLineBorder(new java.awt.Color(0, 0, 0)));

        cmd_SH.setText("Hide");
        cmd_SH.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                cmd_SHActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
                .addContainerGap(558, Short.MAX_VALUE)
                .addComponent(cmd_SH)
                .addContainerGap())
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
                .addContainerGap(236, Short.MAX_VALUE)
                .addComponent(cmd_SH)
                .addContainerGap())
        );

        pnl_2.setBorder(javax.swing.BorderFactory.createLineBorder(new java.awt.Color(0, 0, 0)));

        javax.swing.GroupLayout pnl_2Layout = new javax.swing.GroupLayout(pnl_2);
        pnl_2.setLayout(pnl_2Layout);
        pnl_2Layout.setHorizontalGroup(
            pnl_2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 621, Short.MAX_VALUE)
        );
        pnl_2Layout.setVerticalGroup(
            pnl_2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 270, Short.MAX_VALUE)
        );

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(pnl_2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                .addContainerGap())
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                .addComponent(pnl_2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(17, Short.MAX_VALUE))
        );

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

    private void cmd_SHActionPerformed(java.awt.event.ActionEvent evt) {                                       


        System.out.println(evt.getActionCommand());
        if (evt.getActionCommand().equals("Hide")) {
            pnl_2.setVisible(false);
            cmd_SH.setText("Show");
            this.setSize(643, 294);
            this.pack();


        }
        if (evt.getActionCommand().equals("Show")) {
            pnl_2.setVisible(true);
            cmd_SH.setText("Hide");
            this.setSize(643, 583);
            this.pack();    
        }
    }                                      

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {
                new Style1().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify
    private javax.swing.JButton cmd_SH;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JPanel pnl_2;
    // End of variables declaration
}