Advanced Java Programming - Old Questions

2. Write a Java program to find the sum of two numbers using swing components. Use text fields for input and output. Your program displays output if you press any key in keyboard. Use key adapter to handle  events.

import javax.swing.*;

import java.awt.GridLayout;

import java.awt.event.KeyAdapter;

import java.awt.event.KeyEvent;

public class Addition

{

 JLabel l1, l2, l3;

 JTextField t1, t2, t3;

 JFrame f = new JFrame(); 

 Addition() 

 {

  l1 = new JLabel("First Number:");

  t1 = new JTextField();

  l2 = new JLabel("Second Number:");

  t2 = new JTextField();

  l3 = new JLabel("Press any key");

  t3 = new JTextField();

  t3.addkeyListener(new keychecker());

  f.add(l1);

  f.add(t1);

  f.add(l2);

  f.add(t2);

  f.add(l3);

  f.add(t3);

  f.setSize(250,150);

  f.setLayout(new GridLayout(3,2));

  f.setLocationRelativeTo(null);

  f.setVisible(true);

  f.setDefaultCloseOperation(f.EXIT_ON_CLOSE);  

}

class keychecker extends KeyAdapter{

   public void keyPressed(KeyEvent e)     

   {

        int num1 = Integer.parseInt(t1.getText()); 

        int num2 = Integer.parseInt(t2.getText()); 

        int sum = num1 + num2;

        JOptionPane.showMessageDialog(f, "The sum is" +sum);

        t3.setText(null);

   }

 public static void main(String args[])

 {

    new Addition();

 }

}