How can I hide a JPanel?

Question

I have some JPanels and using the mouse motion listeners you can scribble on them. I want to be able to switch between these panels but the problem is the drawings get wiped off when I use repaint() and frame.add(panel).
Any ideas how else I could try doing this?

Answer 1

Ok thanks everyone. I've taken the MyPanel class from here http://java.sun.com/docs/books/tutorial/uiswing/painting/step3.html
class MyPanel extends JPanel {
    private int squareX = 50;
    private int squareY = 50;
    private int squareW = 20;
    private int squareH = 20;
    public MyPanel() {
        setBorder(BorderFactory.createLineBorder(Color.black));
        addMouseListener(new MouseAdapter() {
            public void mousePressed(MouseEvent e) {
                moveSquare(e.getX(),e.getY());
        addMouseMotionListener(new MouseAdapter() {
            public void mouseDragged(MouseEvent e) {
                moveSquare(e.getX(),e.getY());
    private void moveSquare(int x, int y) {
        int OFFSET = 1;
        if ((squareX!=x) || (squareY!=y)) {
            repaint(squareX,squareY,squareW+OFFSET,squareH+OFFSET);
            squareX=x;
            squareY=y;
            repaint(squareX,squareY,squareW+OFFSET,squareH+OFFSET);
    public Dimension getPreferredSize() {
        return new Dimension(250,200);
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);      
        g.drawString("This is my custom Panel!",10,20);
        g.setColor(Color.RED);
        g.fillRect(squareX,squareY,squareW,squareH);
        g.setColor(Color.BLACK);
        g.drawRect(squareX,squareY,squareW,squareH);
}Now if I use this class to make two panels, how can I hide one and bring the other one up and vice versa, using two buttons? setVisible() still doesn't work properly.
Here's the whole code.
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.SwingUtilities;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.BorderFactory;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseMotionListener;
import java.awt.event.MouseMotionAdapter;
public class PanelTest extends JFrame {
    private MyPanel panelOne;
    private MyPanel panelTwo;
    private BorderLayout layoutManager;
    private PanelTest() {
        layoutManager = new BorderLayout();
        this.setLayout(layoutManager);
        panelOne = new MyPanel();
        panelTwo = new MyPanel();
        panelOne.add(new JLabel("This is Panel One"));
        panelTwo.add(new JLabel("This is Panel Two"));
        setCurrentPanel(panelOne);
        JButton switchButton = new JButton("Switch");
        switchButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if(getCurrentPanel() == panelOne) {
                    setCurrentPanel(panelTwo);
                } else {
                    setCurrentPanel(panelOne);
        this.getContentPane().add(switchButton, BorderLayout.SOUTH);
        this.pack();
        this.setVisible(true);
    private void setCurrentPanel(MyPanel panel) {
        this.getContentPane().add(panel, BorderLayout.CENTER);
        panel.revalidate();
        panel.repaint();
    private JPanel getCurrentPanel() {
        return (JPanel)layoutManager.getLayoutComponent(BorderLayout.CENTER);
    public static void main(String[] args) {
        new PanelTest();
class MyPanel extends JPanel {
    private int squareX = 50;
    private int squareY = 50;
    private int squareW = 20;
    private int squareH = 20;
    public MyPanel() {
        setBorder(BorderFactory.createLineBorder(Color.black));
        addMouseListener(new MouseAdapter() {
            public void mousePressed(MouseEvent e) {
                moveSquare(e.getX(),e.getY());
        addMouseMotionListener(new MouseAdapter() {
            public void mouseDragged(MouseEvent e) {
                moveSquare(e.getX(),e.getY());
    private void moveSquare(int x, int y) {
        int OFFSET = 1;
        if ((squareX!=x) || (squareY!=y)) {
            repaint(squareX,squareY,squareW+OFFSET,squareH+OFFSET);
            squareX=x;
            squareY=y;
            repaint(squareX,squareY,squareW+OFFSET,squareH+OFFSET);
    public Dimension getPreferredSize() {
        return new Dimension(250,200);
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);      
        g.setColor(Color.RED);
        g.fillRect(squareX,squareY,squareW,squareH);
        g.setColor(Color.BLACK);
        g.drawRect(squareX,squareY,squareW,squareH);
}Edited by: atom.bomb on Mar 30, 2010 11:25 AM