MagicSquare

From: Alessandro Mizzoni (alessandro.mizzoni_at_fastwebnet.it)
Date: 08/27/04 

Date: Fri, 27 Aug 2004 01:34:04 +0200

last question!!!
this program create a jpannel "pannello" with a gridlayout(N*N) and a
jpannel"pannello3" with JComboBox ArrayChoice.

how can i change the content of pannello with a new random gridlayout(N*N)
when i clicked on a item of the JComboBox ArrayChoice?
thx!!!!

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.*;

public class QuadratoFrame extends JFrame {
   // keys for putClientProperty
   private final static String PROP_MAT_ROW = "MAT_ROW";
   private final static String PROP_MAT_COL = "MAT_COL";

   private final static int N = 6;
   private final static int MAXELEM = 50;

   private int[][] mat = new int[N][N];
   private JButton[][] jb = new JButton[N][N];
   private JPanel pannello2= new JPanel();
   private JPanel pannello3= new JPanel();
   //private JButton Verifica= new JButton("verifica");
   private JComboBox ArrayChoice;

   public QuadratoFrame()
   {
     CreateRamdom ();
     ArrayChoice=new JComboBox();

     ArrayChoice.addItem("< selezionare matrice>");
     ArrayChoice.addItem("Array Random");
     ArrayChoice.addItem("Array Random2");
     //ArrayChoice.setEditable(true);
     ArrayChoice.addActionListener(new ChoiceListener());

     //pannello3.add(Verifica);
     pannello2.add(ArrayChoice);

     //pannello3.setPreferredSize(new Dimension(120, 100));
     pannello2.setPreferredSize(new Dimension(120, 100));

     getContentPane().add(pannello2, BorderLayout.NORTH);
     //getContentPane().add(pannello, BorderLayout.CENTER);
     //getContentPane().add(pannello3, BorderLayout.SOUTH);
     //pack();
   }

   private ActionListener buttonListener = new ActionListener()
   {
     public void actionPerformed(ActionEvent e)
     {
       JButton pressedButton = (JButton) e.getSource();

       // Get row and column index from the button
       int row =
         ((Integer)
pressedButton.getClientProperty(PROP_MAT_ROW)).intValue();
       int col =
         ((Integer)
pressedButton.getClientProperty(PROP_MAT_COL)).intValue();

       // matrix value
       int value = mat[row][col];

       String input =
         JOptionPane.showInputDialog(
           QuadratoFrame.this,
           "Inserisci un nuovo valore:",
           Integer.toString(value));
       if (input != null)
       {
         // input != null: user did not cancel the dialog
         try
         {
            value = Integer.parseInt(input.trim());
            if (value >= 0 && value < MAXELEM)
           {
             // Yep: change matrix...
             mat[row][col] = value;
             // ...and the text of the button
             pressedButton.setText(Integer.toString(value));
           }
           else
           {
             // Value was not in the range
             throw new NumberFormatException(
               "value must be >= 0 and < " + MAXELEM);
           }
         }
         catch (NumberFormatException ex)
         {
           // Input was invalid: show error dialog
           JOptionPane.showMessageDialog(
             QuadratoFrame.this,
             "Valore inserito: " + input + "\n" + ex.getMessage(),
             "hai inserito un valore non valido, inserire un intero",
             JOptionPane.ERROR_MESSAGE);
         }
       }
     }
   };

 private class ChoiceListener implements ActionListener {

  public void actionPerformed(ActionEvent event) {
      //String currentChoiceName=(String)ArrayChoice.getSelectedItem();
     CreateRamdom ();
}

  private void CreateRamdom (){

 JPanel pannello = new JPanel();
 pannello.setLayout(new GridLayout(N, N));
         Random generator = new Random();
     for (int i = 0; i < N; i++)
       for (int j = 0; j < N; j++)
         mat[i][j] = generator.nextInt(MAXELEM);

     for (int i = 0; i < N; i++)
       for (int j = 0; j < N; j++)
       {
         JButton pulsante = new JButton(Integer.toString(mat[i][j]));
         jb[i][j] = pulsante;
         // XXX pulsante.addMouseListener(leftListener);

         // Set row and col index of the button; used by buttonListener
         pulsante.putClientProperty(PROP_MAT_ROW, new Integer(i));
         pulsante.putClientProperty(PROP_MAT_COL, new Integer(j));

         // Add buttonListener as ActionListener
         pulsante.addActionListener(buttonListener);

       }
       for (int i = 0; i < jb.length; i++)
              for (int j = 0; j < N; j++)
                     pannello.add(jb[i][j]);
        getContentPane().add(pannello, BorderLayout.CENTER);
   }

}