Table with a Checkbox column, unabe to persist the change in values

[Sara Jones]

Hi,

I have a table with 4 columns, out of which the 4th column is a checkBox column. I have used an DefaultCellEditor to edit this column. The problem I am facing is that, when ever I edit the checkbox on the 1st row, it discplays with a tick. But as soon as I check any of the other rows withtin the same column, the previous tick has been lost. How do I persist the value in this case ?

JCheckBox checkBox = new JCheckBox();
            checkBox.setHorizontalAlignment(SwingConstants.CENTER);
            DefaultCellEditor editor = new DefaultCellEditor(checkBox);
            TableColumn checkBoxTableColumn = table.getColumnModel().getColumn(4);
            checkBoxTableColumn.setCellEditor(editor);
            ( (JCheckBox) (editor.getComponent())).addItemListener(new ItemListener() {
                public void itemStateChanged(ItemEvent itemEvent) {
                   updateRecord((itemEvent.getStateChange() == ItemEvent.SELECTED) ? Boolean.TRUE : Boolean.FALSE);
                }
            });

Where UpdateRecord is my custom method where I am writing the data to the database.

Please help me with this one asap.

Thanks in advance.
Sara

[Michael Dunn]

this link is "how to use tables", with demo sample code containing a checkbox column

http://java.sun.com/docs/books/tutorial/uiswing/components/table.html

add your update(true/false) code to the above (can be to just do a system.out.println),
and if the checkbox state persists, compare your code to that of the demo to see what's different

[Sara Jones]

Thanks for the reply. But I have already gone through the table tutorial that you sent. But it was not much help for me since it gives a generic example of how to create column with checkboxes. It would be really helpful if I could get to know what is missing in the code that I pasted for the value to be persisted, infact multiple selection on different rows on the same column should be possible.

Thanks.

[Rob Spoor]

I'd drop the custom check box renderer / editor combination, and use Swing's own mechanism for this:
- let your TableModel return Boolean.class for that column; the values should of course be Boolean objects as well
- let the JTable use its default renderer / editor for that, which will already be a check box because of the previous
- use a TableModelListener to listen for changes to cell values

Alternatively to the last step, you can override your TableModel's setValueAt method:

public void setValueAt(Object value, int row, int column)
{
    super.setValueAt(value, row, column);
    updateRecord(Boolean.TRUE.equals(value));
}