Thread: Traffic Light problems

I am working on a program that simulates a traffic light. The program lets the user select one of three lights: red, yellow, or green. When a radio button is selected, the light is turned on, and only one light can be on at a time.
I have the code written, the only problem that i am having is displaying the traffic light itself. If someone could help me out it would be greatly appreciated.

Here is what i have coded:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
public class trafficLights extends JFrame {
 
 
	private JRadioButton jrbRed, jrbYellow, jrbGreen;
	private boolean jrbRedClicked = false;
	private boolean jrbYellowClicked = false;
	private boolean jrbGreenClicked = false;
 
 
	public static void main(String[] args) {
		trafficLights frame = new trafficLights();
		frame.setTitle("Exercise 17_3");
		frame.setLocationRelativeTo(null);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.pack();
		frame.setVisible(true);
	} // end of main
 
 
public trafficLights() {
 
	JPanel jpRadioButtons = new JPanel();
	jpRadioButtons.setLayout(new FlowLayout());
	jpRadioButtons.add(jrbRed = new JRadioButton("Red"));
	jpRadioButtons.add(jrbYellow = new JRadioButton("Yellow"));
	jpRadioButtons.add(jrbGreen = new JRadioButton("Green"));
	add(jpRadioButtons, BorderLayout.SOUTH);
 
	JPanel drawLight = new JPanel();
    drawLight.setLayout(new BorderLayout());
	add(drawLight, BorderLayout.CENTER);
	drawLight.add(jpRadioButtons, BorderLayout.SOUTH);
 
 
	//keyboard mnemonics
	jrbRed.setMnemonic('R');
	jrbYellow.setMnemonic('Y');
	jrbGreen.setMnemonic('G');
 
	jrbRed.addActionListener(new ActionListener() {
		public void actionPerformed(ActionEvent e) {
			if(jrbRed.isSelected())
			{
				jrbRedClicked = true;
				repaint();
			}
		}
	});
	jrbYellow.addActionListener(new ActionListener() {
				public void actionPerformed(ActionEvent e) {		
			if(jrbYellow.isSelected())
			{
				jrbYellowClicked = true;
				repaint();
			}
		}
	});	
	jrbGreen.addActionListener(new ActionListener() {
				public void actionPerformed(ActionEvent e) {	
			if(jrbGreen.isSelected())
			{
				jrbGreenClicked = true;
				repaint();
			}
		}
	}); // end of actionlistener()
 
} // end of trafficLights()
 
 
protected void paintComponent(Graphics g) {
	super.paintComponents(g);
 
	setBackground(Color.CYAN);
	g.setColor(Color.BLACK);
	g.drawRect(260, 50, 80, 160);
	g.setColor(Color.BLACK);
	g.drawRect(140, 50, 80, 160);
 
	if(jrbRedClicked == true)
	{
		g.setColor(Color.RED);
		g.fillOval(280, 60, 40, 40);
		g.setColor(Color.BLACK);
		g.drawOval(280, 110, 40, 40);
		g.drawOval(280, 160, 40, 40);
		g.drawRect(260, 50, 80, 160);
		jrbRedClicked = false;
	}
 
	if(jrbYellowClicked == true)
	{
		g.setColor(Color.YELLOW);
		g.fillOval(280, 110, 40, 40);
		g.setColor(Color.BLACK);
		g.drawOval(280, 50, 80, 160);
		g.drawOval(280, 160, 40, 40);
		g.drawRect(260, 50, 80, 160);
		jrbYellowClicked = false;
	}
 
	if(jrbGreenClicked == true)
	{
		g.setColor(Color.GREEN);
		g.fillOval(280, 160, 40, 40);
		g.setColor(Color.BLACK);
		g.drawOval(280, 60, 40, 40);
		g.drawOval(280, 110, 40, 40);
		g.drawRect(260, 50, 80, 160);
		jrbGreenClicked = false;
	}
}// end of paint component
 
} // end of public class

Originally Posted by sircamolate

why should i never do:

if(boolean == true)
{
 
}

and do:

if(boolean)
{
 
}

what's the difference in the output/outcome?

Nothing, it's just ugly. Plus it's an additional calculation that you don't have to do. Plus, what if you want to change the meaning of a boolean? You'd have to go back and change all of your if statements to match.