Create a Button Group such that it contains three radio buttons Red, Yellow, Green when red is clicked you want to display “Stop”, when orange is clicked you want to display “ready”, when the green button is clicked Display “Go” and also create a sample Traffic signal demo using rectangle and ovals using 2D graphics.
Implementation:
Example
Java
// Java Program to Implement Traffic signal // Using Java Swing Components // Importing required classes import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
// Main class // Extending JFrame class and // Implementing ItemListener interface public class Traffic_Signal
extends JFrame implements ItemListener {
// Setting the buttons for the layout
JRadioButton jr1;
JRadioButton jr2;
JRadioButton jr3;
// Setting the field area
JTextField j1 = new JTextField( 10 );
ButtonGroup b = new ButtonGroup();
String msg = " " ;
// Initially setting the co-ordinates to 0,0,0
int x = 0 , y = 0 , z = 0 ;
public Traffic_Signal(String msg)
{
super (msg);
setLayout( new FlowLayout());
// Assigning name to the button declared above
// with help of JRadioButton class
jr1 = new JRadioButton( "Red" );
jr2 = new JRadioButton( "Yellow" );
jr3 = new JRadioButton( "Green" );
jr1.addItemListener( this );
jr2.addItemListener( this );
jr3.addItemListener( this );
add(jr1);
add(jr2);
add(jr3);
b.add(jr1);
b.add(jr2);
b.add(jr3);
add(j1);
// Method 1
// To add a window
addWindowListener( new WindowAdapter() {
public void windowClosing(WindowEvent e)
{
// It haults here itself
System.exit( 0 );
}
});
}
// Method 2
// To change colors of traffic signal
public void itemStateChanged(ItemEvent ie)
{
// If it is red
if (ie.getSource() == jr1) {
if (ie.getStateChange() == 1 ) {
// Then display message- Stop
msg = "Stop!" ;
x = 1 ;
// Repainting the box with original one
// Practically black
repaint();
}
else {
msg = "" ;
}
}
// If state is Orange or technically jr2
if (ie.getSource() == jr2) {
if (ie.getStateChange() == 1 ) {
// Then display message-
// Get ready in waiting state
msg = "Get Ready to go!" ;
y = 1 ;
// Again repainting the button
repaint();
}
else {
msg = "" ;
}
}
// If state is Green
if (ie.getSource() == jr3) {
if (ie.getStateChange() == 1 ) {
// Then display message- Go
msg = "Go!!" ;
z = 1 ;
repaint();
}
else {
msg = "" ;
}
}
j1.setText(msg);
}
// Method 3
// handling the paint graphics and
// dimensions of the buttons via
// setting co-ordinates
public void paint(Graphics g)
{
g.drawRect( 100 , 105 , 110 , 270 );
g.drawOval( 120 , 150 , 60 , 60 );
g.drawOval( 120 , 230 , 60 , 60 );
g.drawOval( 120 , 300 , 60 , 60 );
// Case: Red
if (x == 1 ) {
g.setColor(Color.RED);
g.fillOval( 120 , 150 , 60 , 60 );
g.setColor(Color.WHITE);
g.fillOval( 120 , 230 , 60 , 60 );
g.setColor(Color.WHITE);
g.fillOval( 120 , 300 , 60 , 60 );
x = 0 ;
}
// Case: Orange
if (y == 1 ) {
g.setColor(Color.WHITE);
g.fillOval( 120 , 150 , 60 , 60 );
g.setColor(Color.YELLOW);
g.fillOval( 120 , 230 , 60 , 60 );
g.setColor(Color.WHITE);
g.fillOval( 120 , 300 , 60 , 60 );
y = 0 ;
}
// Case: Green
if (z == 1 ) {
g.setColor(Color.WHITE);
g.fillOval( 120 , 150 , 60 , 60 );
g.setColor(Color.WHITE);
g.fillOval( 120 , 230 , 60 , 60 );
g.setColor(Color.GREEN);
g.fillOval( 120 , 300 , 60 , 60 );
z = 0 ;
}
}
// Method 4
// Main driver method
public static void main(String args[])
{
// Creating object of Jframe class inside main()
// method
JFrame jf = new Traffic_Signal( "Traffic Light" );
// Setting size and making traffic signal
// operational using setVisible() method
jf.setSize( 500 , 500 );
jf.setVisible( true );
}
} |
Output: