JTable calculate sum of the last column

Question

I have a JTable witch implements TableModelListener, I have implemented the tableChanged(TableModelEvent event) methode, But I'm not able to detect the right column that was modified. I got col -1, while i'm editing the second or a specific column.

Here is my implementation of tableChanged(TableModelEvent event) methode:

import java.awt.BorderLayout;
import java.awt.EventQueue;
import javax.swing.JDialog;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.event.TableModelEvent;
import javax.swing.event.TableModelListener;
import javax.swing.table.AbstractTableModel;


public class JTableTest extends JDialog{
    private JTable myTable ; 

    public JTableTest() {
        super();

        myTable = new JTable(new myTableModel());
        getContentPane().add(new JScrollPane(myTable),BorderLayout.CENTER);
        pack();
    }

    class myTableModel extends AbstractTableModel implements TableModelListener{

        Object[][] donnees = {
                {"Johnathan", "Sykes","Natation"},
                {"Nicolas", "Van de Kampf","FOOTBALL" },
                {"Damien", "Cuthbert","TENNIS" },
                {"Corinne", "Valance","NATATION"},
                {"Emilie", "Schrödinger","FOOTBALL"},
                {"Delphine", "Duke","TENNIS"},
                {"Eric", "Trump","TENNIS"},
        };

        String[] entetes = {"Prénom", "Nom","SPORT"};

        public myTableModel() {
            addTableModelListener(this);
        }

         public int getRowCount() {
        return donnees.length;

    }

    public int getColumnCount() {
        return entetes.length;
    }

    public String getColumnName(int columnIndex) {
        return entetes[columnIndex];
    }

    public Object getValueAt(int rowIndex, int columnIndex) {
        return donnees[rowIndex][columnIndex];
    }

        @Override
        public void tableChanged(TableModelEvent me) {
            // I wanna get the right column not -1
            System.out.println(me.getColumn());
            switch(me.getType()){
                case TableModelEvent.UPDATE:
                    System.out.println("Updating...");break;
                case TableModelEvent.INSERT:
                    System.out.println("Inserting...");break; 
                case TableModelEvent.DELETE:
                    System.out.println("Delete...");break;
                default :break ;
            }

         }

        @Override
        public void setValueAt(Object value, int row, int col) {
            donnees[row][col] = (String) value;
            fireTableDataChanged();
         }


        @Override
        public boolean isCellEditable(int row, int col) {
            return true; 
         }



}

    public static void main(String[] args)
    {
        EventQueue.invokeLater(new Runnable()
        {
            public void run()
            {
                new JTableTest().setVisible(true);
            }
        });
    }








}

Answer 1

Based on your original question how are we supposed to guess that you are using a custom TableModel? That is why you should always include a proper SSCCE with the question so we don't have to guess what you may or may not be doing.

Why are you using a custom TableModel? There is no need to create a custom model. The DefaultTableModel will do what your custom model does.

Anyway, the problem is indeed with your custom TableModel:

//fireTableDataChanged();
fireTableCellUpdated(row, col);

You didn't change all the data. You only changed the data of one cell so fire the proper event.

Answer 2

The method BigDecimal.add(BigDecimal) returns a BigDecimal. It does not reassign the value.

You should use the following code to reassign somme value:

somme = somme.add((BigDecimal) getValueAt(i, 3));