SudokuWindow

import java.awt.Button;
import java.awt.Checkbox;
import java.awt.CheckboxGroup;
import java.awt.Panel;
import java.awt.TextArea;
import java.awt.Frame;
import java.awt.Color;
import java.awt.Insets;
import java.awt.FlowLayout;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.GridBagLayout;
import java.awt.GridBagConstraints;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.WindowListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowAdapter;

import javax.swing.JTextField;

public class GUI extends Frame
{
  private Button newGame;
  private Button solveGame;
  private Button exitButton;

  private Panel centerPanel;
  private Panel eastPanel;
  private Panel gridBlocks;
  private Panel sudokuField;



  /**Constructor:
   * This GUI is made of two parts (East/Center) in a border layout.
   * The East portion contains two buttons, centered vertically, of
   * the same width. The Center portion contains the Sudoku game and
   * will scale to the window's size after the preferred width of the
   * East portion is satisfied.
   */
  public GUI()
  {
    setLayout(new BorderLayout());
    setBackground(Color.lightGray);
    setTitle("Sudoku!");
    add("East",  getEastPanel());
    add("Center", getCenterPanel());
    pack();


    //Handles the exit call.
    addWindowListener(new WindowAdapter()
    {
      public void windowClosing(WindowEvent e)
      {
        setVisible(false);
        dispose();
        System.exit(0);
      }
    });


  }
  private Panel getCenterPanel()
  {
    if(centerPanel==null)
    {
      Panel centerPanel = new Panel(new BorderLayout());
      centerPanel.add("Center",getGridBlocks());
    }
    return centerPanel;
  }
  private Panel getEastPanel()
  {
    if(eastPanel==null)
    {
      /**
       * 0,1 allows for only 1 column, but any amount
       * of rows. Grid items are always the same size.
      **/
      eastPanel = new Panel(new GridLayout(0,1));
      eastPanel.add(getNGButton());
      eastPanel.add(getSGButton());
    }
    return eastPanel;
  }
  private Button getNGButton()
  {
    if (newGame == null)
      newGame = new Button("New Game");
    return newGame;
  }
  private Button getSGButton()
  {
    if (solveGame == null)
      solveGame = new Button("Solve Game");
    return solveGame;
  }
  private Panel getGridBlocks()
  {
    if(gridBlocks==null)
    {
      Panel gridBlocks = new Panel(new GridLayout(0,3));
      for(int bBlocks=1;bBlocks<=9;bBlocks++)
      {
        /**
         * Generate the inner blocks that will
         * be filled inside the larger grid.
        **/
        Panel smallBlocks = new Panel(new GridLayout(0,3));
        for(int sBlocks=1;sBlocks<=9;sBlocks++)
        {
         JTextField cell = new JTextField(Integer.toString(sBlocks));
         smallBlocks.add(cell);
        }
        gridBlocks.add(smallBlocks);
      }
    }
    return gridBlocks;
  }



  /** A simple main to let us test the GUI */
  public static void main(java.lang.String[] args)
  {
    (new GUI()).setVisible(true);
  }
}