SudokuGUI

import java.awt.Dimension;
import java.awt.Font;
import java.awt.Frame;
import java.awt.Color;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowAdapter;
import java.beans.PropertyChangeListener;

import javax.swing.BorderFactory;
import javax.swing.JPanel;
import javax.swing.JButton;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;

public class GUI extends Frame
{
  private static final long serialVersionUID = 1L;
  private JButton newGame;
  private JButton solveGame;
  private JButton checkAnswers;

  private JPanel centerPanel;
  private JPanel eastPanel;
  private JPanel gridBlocks;

  private int answer;




  /**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(int[][] map, int[][] key)
  {
    setLayout(new BorderLayout());
    setBackground(Color.lightGray);
    UIManager.getLookAndFeel();
    setTitle("Sudoku!");
    setPreferredSize(new Dimension(400, 400));
    add("East",  getEastPanel());
    add("Center", getCenterPanel(map, key));
    pack();


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

    /**Listeners*/

    getNGButton().addActionListener(new ActionListener()
    {
      public void actionPerformed(ActionEvent e)
      {
        //TODO Create method to start new game.
      }
    });
    getCAButton().addActionListener(new ActionListener()
    {
      public void actionPerformed(ActionEvent e)
      {
      }
    });
    getSGButton().addActionListener(new ActionListener()
    {
      public void actionPerformed(ActionEvent e)
      {
        //TODO Add Solve Game button.
      }
    });

    /**EndListeners*/
  }
  private JPanel getCenterPanel(int[][] map, int[][] key)
  {
    if(centerPanel==null)
    {
      centerPanel = new JPanel(new BorderLayout());
      centerPanel.setBorder(BorderFactory.createLineBorder(Color.black));
      centerPanel.add("Center",getGridBlocks(map, key));
    }
    return centerPanel;
  }
  private JPanel 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 JPanel(new GridLayout(0,1));
      eastPanel.add(getNGButton());
      eastPanel.add(getCAButton());
      eastPanel.add(getSGButton());
    }
    return eastPanel;
  }

  /**----Buttons----*/
  private JButton getNGButton()
  {
    if (newGame == null)
      newGame = new JButton("New Game");
    return newGame;
  }
  private JButton getCAButton()
  {
    if (checkAnswers == null)
      checkAnswers = new JButton("Check Answers");
    return checkAnswers;
  }
  private JButton getSGButton()
  {
    if (solveGame == null)
      solveGame = new JButton("Solve Game");
    return solveGame;
  }
  /**----EndButtons----*/

//  private void checkAnswers(int[][] map)
//  {
//    for(int i=0;i<map.length;i++)
//
//  }

  private JPanel getGridBlocks(int[][] map, int[][] key)
  {
    if(gridBlocks==null)
    {
      gridBlocks = new JPanel(new GridLayout(0,3));
      for(int bBlocks=0;bBlocks<9;bBlocks++)
      {
        /**
         * Generate the inner blocks that will
         * be filled inside the larger grid.
        **/
        JPanel smallBlocks = new JPanel(new GridLayout(0,3));
        smallBlocks.setBorder(BorderFactory.createLoweredBevelBorder());
        Font font = new Font(smallBlocks.getFont().getName(),smallBlocks.getFont().getStyle(),35);
        JTextField[][] cells = new JTextField[9][9];
        for(int sBlocks=0;sBlocks<9;sBlocks++)
        {
          //Some math to determine current position aware of offset.
         int row = sBlocks / 3 + (bBlocks / 3) * 3;
         int col = sBlocks % 3 + (bBlocks % 3) * 3;
         final int ref = map[row][col];

         //If the reference == 0, print blank else print the reference.
         cells[row][col] = new JTextField(ref==0?"":Integer.toString(ref));
         final JTextField cell = cells[row][col];

         //Lock cells that already have a correct value based on original map.
         if(ref!=0) cell.setEditable(false);
         //No need to create a listener if the cell is locked.


         /**
          * This will "listen" to each JTextField for a change.
          * Changes will prompt a check, if the check is successful
          * the cell's background will change to green. If the check
          * shows that the number entered is wrong then you get a red
          * background. If the cell becomes blank you get back to white.
         **/

         else cell.addActionListener(new ActionListener()
         {
           public void actionPerformed(ActionEvent event)
           {
             answer = ref;
             JTextField cell = (JTextField) event.getSource();
             System.out.print(cell.getText()+" response triggered..."+answer);
             //Trim cells that are >1 length.
             if(cell.getText().length()>1)
             {
               String str = cell.getText();
               str = str.replaceAll("(.)*", "$1");
               System.out.println(cell.getText());
               cell.setText(str);
               System.out.println("Changed to: " + cell.getText());
             }
           }
         });

         //Sets the cell's property name for callback later.
         cell.getDocument().getProperty("val");
         cell.setFont(font);

         //Assigns the cell to the current 3x3 block.
         smallBlocks.add(cell);
        }

        //Assigns all of the the 3x3 blocks to the 9x9 grid.
        gridBlocks.add(smallBlocks);
      }
    }
    return gridBlocks;
  }


  /** A simple main to let us test the GUI */
  public static void main(java.lang.String[] args)
  {
    int[][] map=new int[9][9];
    int[][] key=new int[9][9];
    (new GUI(map,key)).setVisible(true);
  }
}