Two group layouts inside one another

Question

Hi!
I use group layout to add two buttons to a panel. Then I use group layout again to add that panel on top of my applet's content pane. For some reason the second button shows only after I move mouse over it. I tried different things like invoking repaint method of the second button or drawing via paint component method (method paintComponent(Graphics g)). Any ideas why the repaint method of the other button is not invoked?
import java.awt.*;
import java.lang.reflect.InvocationTargetException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.*;
import javax.swing.GroupLayout.SequentialGroup;
public class TestButton extends JApplet {
* Initialization method that will be called after the applet is loaded
* into the browser.
public void init() {
try {
// TODO start asynchronous download of heavy resources
SwingUtilities.invokeAndWait(new Runnable() {
public void run() {
setSize(new Dimension(300, 300));
// setBackground(Color.black);
Container c = getContentPane();
c.setBackground(Color.GREEN);
final JButton button1 = new JButton() {
@Override
public void paint(Graphics g) {
super.paint(g);
g.setColor(Color.RED);
g.fillRect(0, 0, 100, 100);
final JButton button2 = new JButton() {
@Override
public void paint(Graphics g) {
super.paint(g);
g.setColor(Color.RED);
g.fillRect(0, 0, 100, 100);
JPanel panelBig = new JPanel() {
@Override
public void paint(Graphics g) {
super.paint(g);
g.setColor(Color.YELLOW);
g.fillRect(0, 0, 200, 200);
GroupLayout glBig = new GroupLayout(panelBig);
SequentialGroup horBig = glBig.createSequentialGroup();
SequentialGroup verBig = glBig.createSequentialGroup();
horBig.addComponent(button1, 100, 100, 100);
verBig.addComponent(button1, 100, 100, 100);
horBig.addComponent(button2, 100, 100, 100);
verBig.addComponent(button2, 100, 100, 100);
glBig.setHorizontalGroup(horBig);
glBig.setVerticalGroup(verBig);
panelBig.setLayout(glBig);
// c.add(button1);
GroupLayout gl = new GroupLayout(c);
SequentialGroup hor = gl.createSequentialGroup();
SequentialGroup ver = gl.createSequentialGroup();
hor.addComponent(panelBig, 200, 200, 200);
ver.addComponent(panelBig, 200, 200, 200);
gl.setHorizontalGroup(hor);
gl.setVerticalGroup(ver);
c.setLayout(gl);
} catch (InterruptedException ex) {
Logger.getLogger(TestButton.class.getName()).log(Level.SEVERE, null, ex);
} catch (InvocationTargetException ex) {
Logger.getLogger(TestButton.class.getName()).log(Level.SEVERE, null, ex);
// TODO overwrite start(), stop() and destroy() methods

Answer 1

This would be because you overrided the paint method.
JPanel panelBig = new JPanel() {
    @Override
    public void paint(Graphics g) {
        super.paint(g);
        g.setColor(Color.YELLOW);
        g.fillRect(0, 0, 200, 200);
};The call to super.paint(g) paints the component, the border, and the children. You then proceed to fill in a yellow rectangle over everything that was painted in the panel. The solution, of course, is to do it the correct way and override paintComponent(...) as you are suppose to do for Swing.