JTable : Setting Column Resize Off On MarginChanged Event

[Kumar Srivatsa]

Hello Everyone,

I am trying to set column resizing off on a table when someone drags a column in a Jtable.

I made a small modification to the SimpleTableDemo that turns the column resizing on the table off when a column is physically dragged. I added a column model listener and turn the column resizing off on the columnMarginChanged event (Lines 59 - 60)

  


import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.event.TableColumnModelListener;
import javax.swing.event.TableColumnModelEvent;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ListSelectionEvent;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

public class SimpleTableDemo extends JPanel {
    private boolean DEBUG = false;

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

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

        Object[][] data = {
            {"Mary", "Campione",
                "Snowboarding", new Integer(5), new Boolean(false)},
            {"Alison", "Huml",
                "Rowing", new Integer(3), new Boolean(true)},
            {"Kathy", "Walrath",
                "Knitting", new Integer(2), new Boolean(false)},
            {"Sharon", "Zakhour",
                "Speed reading", new Integer(20), new Boolean(true)},
            {"Philip", "Milne",
                "Pool", new Integer(10), new Boolean(false)}
        };

        final JTable table = new JTable(data, columnNames);
        table.setPreferredScrollableViewportSize(new Dimension(500, 70));
        table.setFillsViewportHeight(true);
        table.getColumnModel().addColumnModelListener(new TableColumnModelListener() {
            public void columnAdded(TableColumnModelEvent p_event) {
                // Doing nothing
            }

            public void columnRemoved(TableColumnModelEvent p_event) {
                // Doing nothing
            }

            public void columnMoved(TableColumnModelEvent p_event) {
                // Doing nothing
            }

            public void columnMarginChanged(ChangeEvent p_event) {
                if (table.getTableHeader().getResizingColumn() != null){
			table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
			}
                    
            }

            public void columnSelectionChanged(ListSelectionEvent p_event) {
            }
        });


        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);
    }
	

    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.
        JPanel newpanel = new JPanel();
        newpanel.setMinimumSize(new Dimension(100, 100));
        SimpleTableDemo newContentPane = new SimpleTableDemo();
        newContentPane.setOpaque(true); //content panes must be opaque
        newpanel.add(newContentPane);
        frame.setContentPane(newpanel);

        //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();
            }
        });
    }
}
  

The issue here is that the table columns seem to stutter and not properly resize when the column is dragged. Eventually once the scrollbar comes in and the mouse is released the column resizing seems to turn off and columns are resized.

Any ideas as to what is going on here ??


Thanks,
Kumar

[Kumar Srivatsa]

Problem solved. I realized what I was doing wrong here .

The JTable resizes the columns to defaults when the AUTO_RESIZE_OFF is invoked.. at the same time a drag action by the user caused the stuttering behavior.