SUDOKU game problem

[bumblyb33]

Hello

I am trying to program an online sudoku game, and the layout of the game is a grid of 9x9 JTextFields. So, I'm arranging these 81 Fields in a panel, however, I need to have some sort of line between each 3x3 block. If anyone has ever played sudoku, you'd know what I mean. Any ideas how to create these lines?
Thanks for any advice,

bumblyb33

[Fubarable]

One solution: create 9 JPanels to each hold 9 of your JTextFields. Then add a border to the JPanels.

[Fubarable]

For example:

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridLayout;

import javax.swing.BorderFactory;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingConstants;

public class SudokuEg
{
  private static final Dimension FIELD_SIZE = new Dimension(60, 60);
  private static final int BORDER_WIDTH = 3;
  private static final float FONT_POINTS = 25;
  private JPanel mainPanel = new JPanel();
  private JPanel[][] subPanels = new JPanel[3][3];
  private JTextField[][] fields = new JTextField[9][9];
  

  public SudokuEg()
  {
    mainPanel.setBorder(BorderFactory.createLineBorder(Color.black, BORDER_WIDTH));
    mainPanel.setLayout(new GridLayout(3, 3));
    
    // create 3x3 grid of sub-panels,
    // add a line border to each sub-panel
    // and add to main panel
    for (int i = 0; i < subPanels.length; i++)
    {
      for (int j = 0; j < subPanels[i].length; j++)
      {
        subPanels[i][j] = new JPanel(new GridLayout(3, 3));
        subPanels[i][j].setBorder(
          BorderFactory.createLineBorder(Color.black, BORDER_WIDTH));
        mainPanel.add(subPanels[i][j]);
      }
    }
    
    // create all JTextFields
    // set fields preferred size, font, center text
    // and add to sub-panels
    for (int i = 0; i < fields.length; i++)
    {
      for (int j = 0; j < fields[i].length; j++)
      {
        fields[i][j] = new JTextField();
        fields[i][j].setPreferredSize(FIELD_SIZE);
        Font font = fields[i][j].getFont().deriveFont(Font.BOLD, FONT_POINTS);
        fields[i][j].setFont(font);
        fields[i][j].setHorizontalAlignment(SwingConstants.CENTER);
        subPanels[i/3][j/3].add(fields[i][j]);
      }
    }
  }

  public JComponent getPanel()
  {
    return mainPanel;
  }

  private static void createAndShowGUI()
  {
    JFrame frame = new JFrame("SudokuEg Application");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().add(new SudokuEg().getPanel());
    frame.pack();
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
  }

  public static void main(String[] args)
  {
    javax.swing.SwingUtilities.invokeLater(new Runnable()
    {
      public void run()
      {
        createAndShowGUI();
      }
    });
  }
}