Question
Program:
//Displays a frame containing a three button. Pressing the
//button causes the background of the frame to change from
//white to define color.
import java.awt.*;
import java.awt.event.*;
import java.awt.Button;
public class threecolor {
public static void main(String[] args) {
Frame f = new ChangethreeColorFrame("Colors");
f.setSize(210, 200);
f.setVisible(true);
}
}
//Frame class
class ChangethreeColorFrame extends Frame {
public ChangethreeColorFrame(String title) {
super(title);
setLayout(null);
setBackground(Color.white);
//Add button to frame and attach listener
Button b1 = new Button("Red");
b1.setBounds(20, 150, 50, 30);
add(b1);
b1.addActionListener(new ButtonListener());
Button b2 = new Button("Blue");
b2.setBounds(80, 150, 50, 30);
add(b2);
b2.addActionListener(new ButtonListener());
Button b3 = new Button("Green");
b3.setBounds(140, 150, 50, 30);
add(b3);
b3.addActionListener(new ButtonListener());
//Attach window listener
addWindowListener(new WindowCloser());
}
//Listener for button
class ButtonListener implements ActionListener {
public void actionPerformed(ActionEvent evt) {
if (evt.getActionCommand().equals("Red"))
setBackground(Color.RED);
else if (evt.getActionCommand().equals("Blue"))
setBackground(Color.BLUE);
else if (evt.getActionCommand().equals("Green"))
setBackground(Color.GREEN);
else
setBackground(Color.white);
}
}
//Listener for window
class WindowCloser extends WindowAdapter {
public void windowClosing(WindowEvent evt) {
System.exit(0);
}
}
}
