Add JButton at runtime

Question

I have two JPanel's in a JFrame. First JPanel has a JButton.
Now what i want is that when i click that JButton, a JButton should be added in the other JPanel.
this is what iv tried
public void actionPerformed(ActionEvent ae)
panel.add(new JButton("ok"));
panel.repaint();
but the above code is not working, please suggest...

Answer 1

revalidate
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Example {
    public static void main(String[] args) {
        JPanel north = new JPanel();
        final JPanel south = new JPanel(new GridLayout(0,4,2,2));
        JButton btn = new JButton("create another button");
        north.add(btn);
        btn.addActionListener(new ActionListener(){
            int count;
            public void actionPerformed(ActionEvent evt) {
                ++count;
                south.add(new JButton("button # " + count));
                south.revalidate(); // <<<---<<<
                //south.repaint(); //sometimes this is needed, too
        JFrame f = new JFrame("Example");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Container cp = f.getContentPane();
        cp.add(north, BorderLayout.NORTH);
        cp.add(south, BorderLayout.SOUTH);
        f.setSize(400,300);
        f.setLocationRelativeTo(null);
        f.setVisible(true);
}