Thread: JRadioButton Event Handling Help?

Hello. I have been staring at this program and I cannot figure out what is wrong with it. Basically it is a stoplight whose lights are controlled by radio buttons. The program runs with no errors but the buttons do not work. I have a listener and have defined the actionperformed class but it is not working. I will post the code. Any help would be greatly appreciated.
Thanks,
Austin

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
class Lights extends JPanel
{
  public JRadioButton btnR;
  public JRadioButton btnY;
  public JRadioButton btnG;
  public JRadioButton btnO;
  public Color rColor;
  public Color yColor;
  public Color gColor;
  public Color general;
 
  public void paintComponent ( Graphics g)
  {
 
    super.paintComponent ( g );
 
 
    general= getBackground();
    // Set foreground color
    g.setColor (Color.black);
 
    // get the size of the drawing area		
    Dimension size = this.getSize();
 
    // Bounding rectangle for the traffic lights
    int rectWidth = (int) (0.4 * size.width);
    int rectHeight = (int) (0.8 * size.height);
 
    // Location where the rectangle is to be drawn
    int xint = (int) (0.3 * size.width);
    int yint = (int) (0.1 * size.height);
 
    // Draw bounding rectangle
    g.drawRect (xint, yint, rectWidth, rectHeight);
 
    // Draw three circles inside the rectangle
    int circleHeight = (int) (0.9 * rectHeight / 3);
    int circleWidth = (int) (0.8 * rectWidth);
    int circleDia = (circleHeight < circleWidth)? circleHeight : circleWidth;
    int xOffset = (rectWidth - circleDia) / 2;
    int yOffset = (rectHeight - 3 * circleDia) / 4;
 
    xint = xint + xOffset; 
    yint = yint + yOffset;
 
    // Draw the red light 
    g.setColor(getBackground());
    g.setColor(rColor);
    g.fillOval (xint, yint, circleDia, circleDia);
    g.setColor(Color.black);
    g.drawOval (xint, yint, circleDia, circleDia);
    g.setColor(getBackground());
    rColor= general;
 
    // Draw the yellow light
    yint = yint + circleDia + yOffset;
    g.setColor(yColor);
    g.fillOval (xint, yint, circleDia, circleDia);
    g.setColor(Color.black);
    g.drawOval (xint, yint, circleDia, circleDia);
    g.setColor(getBackground());
    yColor= general;
 
    // Draw the green light
    yint = yint + circleDia + yOffset;
    g.setColor(gColor);
    g.fillOval (xint, yint, circleDia, circleDia);
    g.setColor(Color.black);
    g.drawOval (xint, yint, circleDia, circleDia);
    g.setColor(getBackground());
    gColor= general;
 
  }
 
 
}
 
public class TrafficLights
{
  public static void main (String[] args)
  {
 
	Lights lightPanel = new Lights();
	lightPanel.setBorder ( BorderFactory.createEmptyBorder (10, 20, 10, 20 ));
 
    // Create buttons to simulate switches
    lightPanel.btnR = new JRadioButton ("Red");
    lightPanel.btnY = new JRadioButton ("Yellow");
    lightPanel.btnG = new JRadioButton ("Green");
    lightPanel.btnO = new JRadioButton ("Off");
    ButtonGroup switches = new ButtonGroup ();
    switches.add (lightPanel.btnR);
    switches.add (lightPanel.btnY);
    switches.add (lightPanel.btnG);
    switches.add (lightPanel.btnO);
 
    JPanel switchPanel = new JPanel();
    switchPanel.setBorder ( BorderFactory.createEmptyBorder (10, 20, 10, 20 ));
    switchPanel.setLayout (new GridLayout (1, 4));
    switchPanel.add (lightPanel.btnR);
    switchPanel.add (lightPanel.btnY);
    switchPanel.add (lightPanel.btnG);
    switchPanel.add (lightPanel.btnO);
 
 
 
    JFrame frame = new JFrame ("Traffic Lights");
    frame.getContentPane().add( lightPanel, BorderLayout.CENTER);
    frame.getContentPane().add( switchPanel, BorderLayout.SOUTH);
    frame.setSize (400, 600);
    frame.setVisible (true);
    frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
 
  }
}
 
class LightButtonListener implements ActionListener
{
  private Lights theLight;
  //public Color c;
  public LightButtonListener ( Lights aLight )
  {
    theLight = aLight;
    //create listener and add buttons to it
    theLight.btnR.addActionListener ( this );
    theLight.btnY.addActionListener ( this );
    theLight.btnG.addActionListener ( this );
    theLight.btnO.addActionListener ( this );
  }
 
  public void actionPerformed ( ActionEvent evt )
  {
    if ( evt.getSource() == theLight.btnR)
    {
      theLight.rColor= Color.red;
      theLight.repaint();
    }
    else if (evt.getSource() == theLight.btnY)
    {
    	theLight.yColor= Color.yellow;
        theLight.repaint();
    }
    else if (evt.getSource() == theLight.btnG)
    {
    	theLight.rColor= Color.green;
        theLight.repaint();
    }
    else if (evt.getSource() == theLight.btnO)
    {
        theLight.repaint();
    }
 
  }
 
}

I do not see any code which actually creates the LightButtonListener, eg in your main you must create this Object passing the Lights instance to it, otherwise the code which adds the listeners never gets called.

Oh yes. Thanks so much. I knew it was something dumb like that.