How do I make this program generate a new problem once the button is hit

Question

Here is the code... appreciate any help given
How do I make this program generate a new set of problem when the "NEXT" button is clicked and continue until the END button is hit
package javaapplication3;
import java.awt.GridLayout;
import java.awt.Window;
import javax.swing.*;
import java.awt.event.*;
* @author Sylvester Saulabiu
class Grid extends JFrame{
    final int score = 0;
    final int total = 0;
    Grid(){
        //Set Layout of Flashcard
        setLayout(new GridLayout(4, 4, 2 , 2));
        //Create Panels
        JPanel p2 = new JPanel();
        JPanel p3 = new JPanel();
        final JPanel p1 = new JPanel();
        //Create Radio buttons & group them
        ButtonGroup group = new ButtonGroup();
        final JRadioButton ADD = new JRadioButton("Addition");
        final JRadioButton SUB = new JRadioButton("Subtraction");
        final JRadioButton MUL = new JRadioButton("Multiplication");
        final JRadioButton DIV = new JRadioButton("Division");
        p2.add(ADD);
        p2.add(SUB);
        group.add(ADD);
        group.add(SUB);
        group.add(MUL);
        group.add(DIV);
        p2.add(ADD);
        p2.add(SUB);
        p2.add(DIV);
        p2.add(MUL);
        //Create buttons
        JButton NEXT = new JButton("NEXT");
        JButton END = new JButton("End");
        //Create Labels
        JLabel l1 = new JLabel("First num");
        JLabel l2 = new JLabel("Second num");
        JLabel l3 = new JLabel("Answer:");
        JLabel l4 = new JLabel("Score:");
        final JLabel l5 = new JLabel("");
        JLabel l6 = new JLabel("/");
        final JLabel l7 = new JLabel("");
        //Create Textfields
        final JTextField number = new JTextField(Generator1());
        final JTextField number2 = new JTextField(Generator1());
        final JTextField answer = new JTextField(5);
        //Add to panels
        p1.add(l1);
        p1.add(number);
        p1.add(l2);
        p1.add(number2);
        p1.add(l3);
        p1.add(answer);
        p1.add(l4);
        p1.add(l5);
        p1.add(l6);
        p1.add(l7);
        p3.add(NEXT);
        p3.add(END);
        //Add panels
        add(p2);
        add(p1);
        add(p3);
        //Create Listners
  NEXT.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
         int answer1 = 0;
         //Grab the numbers entered
         int numm1 = Integer.parseInt(number.getText());
         int numm2 = Integer.parseInt(number2.getText());
         int nummsanswer = Integer.parseInt(answer.getText());
         //Set the score and total into new variabls
         int nummscore = score;
         int nummtotal = total;
         //Check if the add radio button is selected if so add
         if (ADD.isSelected() == true){
             answer1 = numm1 + numm2;
         //otherwise check if the subtract button is selected if so subtract
         else if (SUB.isSelected() == true){
             answer1 = numm1 - numm2;
         //check if the multiplication button is selected if so multiply
         else if (MUL.isSelected() == true){
             answer1 = numm1 * numm2;
         //check if the division button is selected if so divide
         else if (DIV.isSelected() == true){
             answer1 = numm1 / numm2;
         //If the answer user entered is the same with th true answer
         if (nummsanswer == answer1){
             //add to the total and score
             nummtotal += 1;
             nummscore += 1;
             //Convert the input back to String
             String newscore = String.valueOf(nummscore);
             String newtotal = String.valueOf(nummtotal);
             //Set the text
             l5.setText(newscore);
             l7.setText(newtotal);
         //Otherwise just increase the total counter
         else {
             nummtotal += 1;
             String newtotal = String.valueOf(nummtotal);
             l7.setText(newtotal);
  //Create End listener
END.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        // get the root window and call dispose on it
        Window win = SwingUtilities.getWindowAncestor(p1);
        win.dispose();
String Generator1(){
     int randomnum;
     randomnum = (1 + (int)(Math.random() * 20));
     String randomnumm = String.valueOf(randomnum);
     return randomnumm;
public class Main {
     * @param args the command line arguments
    public static void main(String[] args) {
        // TODO code application logic here
        JFrame frame = new Grid();
        frame.setTitle("Flashcard Testing");
        frame.setSize(500, 200);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
}Edited by: SirSaula on Dec 5, 2009 4:39 PM

Answer 1

Extract code into methods, so that when an action is performed a method is called. That way you can reuse the method for purposes such as resetting textfields to their default values, scores to default values, etc.
You can go one step further and seperate the GUI layer from the processing layer, by deriving classes that for example maintain and calculate a score.
Mel