Fifth Week Term Work Program 2

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);

}

}

}