How to get newly updated data in a cell in a DefaultTableModel

Question

I create a table from DefaultTableModel, and then I use table.getModel().setValueAt(value,row,col) to add the 1st value in a cell. However, when I click the mouse on that cell and change the data inside to the 2nd value. and then I get that value back by getValueAt(row,col), it always returns that first value even though on the table the 2nd value is displayed in the cell. What am I wrong?

Hope you understand my messy idea.

Thanks a lot! //////////////

Thank you for your answer, I have copied the code from the link you gave me and run it. I have a test like this: I modify value at the Cell(0,3) and then try getting that value out (by click the okButton) But the value is the old, NOT the new one?

Here is the code :

package DialogExample;


import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.event.TableModelEvent;
import javax.swing.event.TableModelListener;
import javax.swing.table.TableModel;

import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

public class SimpleTableDemo extends JPanel implements TableModelListener {
private boolean DEBUG = false;
 JTable table;
 JButton okButton;

public JButton getOkButton() {
    okButton = new JButton("OK");
    okButton.addActionListener(new ActionListener() {

        @Override //// modify value at the Cell(0,3) and then get that value out. 
        /// the value is the old, NOT the new one?????
        public void actionPerformed(ActionEvent arg0) {
            int i = (Integer) table.getModel().getValueAt(0, 3);
            System.out.print(i);
        }
    });
    return okButton;
}

public SimpleTableDemo() {
    super(new GridLayout(1, 0));


    String[] columnNames = { "First Name", "Last Name", "Sport",
            "# of Years", "Vegetarian" };

    Object[][] data = {
            { "Kathy", "Smith", "Snowboarding", new Integer(5),
                    new Boolean(false) },
            { "John", "Doe", "Rowing", new Integer(3), new Boolean(true) },
            { "Sue", "Black", "Knitting", new Integer(2),
                    new Boolean(false) },
            { "Jane", "White", "Speed reading", new Integer(20),
                    new Boolean(true) },
            { "Joe", "Brown", "Pool", new Integer(10), new Boolean(false) } };

    table = new JTable(data, columnNames);
    table.setPreferredScrollableViewportSize(new Dimension(500, 70));
    table.setFillsViewportHeight(true);

    if (DEBUG) {
        table.addMouseListener(new MouseAdapter() {
            public void mouseClicked(MouseEvent e) {
                printDebugData(table);
            }
        });
    }

    // Create the scroll pane and add the table to it.
    JScrollPane scrollPane = new JScrollPane(table);

    // Add the scroll pane to this panel.
    add(scrollPane);
    add(getOkButton());
}

public void tableChanged(TableModelEvent e) {
    int row = e.getFirstRow();
    int column = e.getColumn();
    TableModel model = (TableModel) e.getSource();
    String columnName = model.getColumnName(column);
    Object data = model.getValueAt(row, column);

    // Do something with the data...
}

private void printDebugData(JTable table) {
    int numRows = table.getRowCount();
    int numCols = table.getColumnCount();
    javax.swing.table.TableModel model = table.getModel();

    System.out.println("Value of data: ");
    for (int i = 0; i < numRows; i++) {
        System.out.print("    row " + i + ":");
        for (int j = 0; j < numCols; j++) {
            System.out.print("  " + model.getValueAt(i, j));
        }
        System.out.println();
    }
    System.out.println("--------------------------");
}

/**
 * Create the GUI and show it. For thread safety, this method should be
 * invoked from the event-dispatching thread.
 */
private static void createAndShowGUI() {
    // Create and set up the window.
    JFrame frame = new JFrame("SimpleTableDemo");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    // Create and set up the content pane.
    SimpleTableDemo newContentPane = new SimpleTableDemo();
    newContentPane.setOpaque(true); // content panes must be opaque
    frame.setContentPane(newContentPane);

    // Display the window.
    frame.pack();
    frame.setVisible(true);
}

public static void main(String[] args) {
    // Schedule a job for the event-dispatching thread:
    // creating and showing this application's GUI.
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            createAndShowGUI();
        }
    });
}

}

Please post [SSCCE](http://sscce.org/) that demonstrates the problem. — tenorsax, Jul 20 '12 at 07:00

score 2 · Answer 1 · answered Jul 20 '12 at 11:31

now could be works,
have to define TableModel with proper ColumnClass

code

import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.event.TableModelEvent;
import javax.swing.event.TableModelListener;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableModel;

public class SimpleTableDemo extends JPanel implements TableModelListener {

    private static final long serialVersionUID = 1L;
    private boolean DEBUG = false;
    private JTable table;
    private JButton okButton;
    private String[] columnNames = {"First Name", "Last Name", "Sport", "# of Years", "Vegetarian"};
    private Object[][] data = {{"Kathy", "Smith", "Snowboarding", new Integer(5), (false)},
        {"John", "Doe", "Rowing", new Integer(3), (true)},
        {"Sue", "Black", "Knitting", new Integer(2), (false)},
        {"Jane", "White", "Speed reading", new Integer(20), (true)},
        {"Joe", "Brown", "Pool", new Integer(10), (false)}};
    private TableModel model = new DefaultTableModel(data, columnNames) {

        private static final long serialVersionUID = 1L;

        @Override
        public Class<?> getColumnClass(int column) {
            return getValueAt(0, column).getClass();
        }
    };

    private JButton getOkButton() {
        okButton = new JButton("OK");
        okButton.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent ae) {
                int i = (Integer) table.getModel().getValueAt(0, 3);
                System.out.print(i);
            }
        });
        return okButton;
    }

    public SimpleTableDemo() {
        super(new GridLayout(1, 0));
        model.addTableModelListener(this);
        table = new JTable(model);
        table.setPreferredScrollableViewportSize(new Dimension(500, 70));
        table.setFillsViewportHeight(true);
        JScrollPane scrollPane = new JScrollPane(table);
        add(scrollPane);
        add(getOkButton());
    }

    public void tableChanged(TableModelEvent e) {
        int row = e.getFirstRow();
        int column = e.getColumn();
        model = (TableModel) e.getSource();
        String columnName = model.getColumnName(column);
        Object datas = model.getValueAt(row, column);
        System.out.println("Column ---> " + columnName + ", new value is " + datas);
    }

    private static void createAndShowGUI() {
        JFrame frame = new JFrame("SimpleTableDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        SimpleTableDemo newContentPane = new SimpleTableDemo();
        newContentPane.setOpaque(true); // content panes must be opaque
        frame.setContentPane(newContentPane);
        frame.pack();
        frame.setVisible(true);
    }

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

            public void run() {
                createAndShowGUI();
            }
        });
    }
}

score 1 · Answer 2 · answered Jul 20 '12 at 10:03

1

Not exactly sure what you are trying to do without an SSCCE, but please read the tutorial about JTables in general and, more specific, model changes first.

answered Jul 20 '12 at 10:03

moeTi

3,884
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How to get newly updated data in a cell in a DefaultTableModel

2 Answers2