Listening events on another class

Question

Hi, I am doing a program that uses differents jpanels, So I need to set a button enabled when an event ocurrs in another panel, how can I do that. the problem is that the panel from wich I need to listen is another class.
please can someone help me posting some small code that shows how can I listen events on other classes. I think I am able to detect it changing a static variable on another class and having a thread that verify its state, But i dont want to do that, I want to use a listener or any other similar way.

Answer 1

there's a lot of ways so it depends on the architecture of your program.
here's a couple of ideas to play with.
import javax.swing.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
public class MyFrame extends javax.swing.JFrame {
    public MyFrame(AnotherClass a) {
        JButton b1 = new JButton("OK");
        b1.addActionListener(a);
        JButton b2 = new JButton(a.getButtonAction("Cancel"));
        getContentPane().setLayout(new java.awt.FlowLayout());
        getContentPane().add(b1);
        getContentPane().add(b2);
        setLocationRelativeTo(null);
        pack();
        addWindowListener(new WindowAdapter(){
           public void windowClosing(WindowEvent we){
               System.exit(0);
    public static void main(String[] args){
        new MyFrame(new AnotherClass()).setVisible(true);
import javax.swing.Action;
import javax.swing.AbstractAction;
import java.awt.event.*;
public class AnotherClass implements ActionListener {   
    private Action a;//cancel action
    public AnotherClass() {}
    private void setEnabled(boolean b){
        a.setEnabled(b);
    //cancel action
    public Action getButtonAction(String name){
        a =  new AbstractAction(name){
           public void actionPerformed(ActionEvent ae){
               System.out.println("Cancel");
        return a;
    public void actionPerformed(ActionEvent e) {
        //ok button action
        System.out.println("okay");
}