Swing JCombobox and JTable issue

[binayakumar patel]

Hi,

I am unable to add a Combo box in JTable 2nd column of each row with different value. Please help me.. I already try lots of time with many example but I man unable to change the ComboBox value in every row. Is it possible to rander a particular column with different component in every row ?

[Rob Prime]

TableCellRenderer.getTableCellEditorComponent takes both the row and column numbers, so you can use that to your advantage. For example:

class MyTableCellEditor extends DefaultCellEditor
{
    public MyTableCellEditor()
    {
        super(new JComboBox());
    }

    public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int row, int column)
    {
        JComboBox combo = (JComboBox)super.getTableCellEditorComponent(table, value, isSelected, row, column);
        combo.removeAllItems();
        Object[] items = getItemsForCell(row, column); // you'll need to implement this method yourself
        for (Object item: items)
        {
            combo.addItem(item);
        }
        return combo;
    }
}

Of course you can use a Collection or List instead of an Object[], but the principle is the same.

[binayakumar patel]

Thanks Rob Prime. It is working fine.
yours solution helps me a lot.

I have one more doubt that , can not we Render the same cell with different component. Like the same column in first row with JCombo Box and the same column in next row with JTextField.

I have a Map, which I have to display in n-rows and 3-column table ... where for rew columns the value need to select from combobox and few need to enter. The number of rows we cant define... because it is dynamic.

[Rob Prime]

Sure, just return a JTextField from that method.

The following class for instance uses a JComboBox, JTextField and a JCheckBox:

class MyCellEditor implements TableCellEditor
{
    private TableCellEditor comboBox = new DefaultCellEditor(new JComboBox());
    private TableCellEditor textField = new DefaultCellEditor(new JTextField());
    private TableCellEditor checkBox = new DefaultCellEditor(new JCheckBox());

    private TableCellEditor current;

    public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int row, int column)
    {
        if (shouldUseComboBox(value, row, column))
        {
            current = comboBox;
            JComboBox combo = (JComboBox)current.getTableCellEditorComponent(...);
            // fill as before
            return combo;
        }
        if (shouldUseCheckBox(value, row, column))
        {
            current = checkBox;
            JCheckBox check = (JCheckBox)current.getTableCellEditorComponent(...);
            // set selected as needed
            return check;
        }
        // default to text field
        current = textField;
        JTextField field = (JTextField)curernt.getTableCellEditorComponent(...);
        // modify as needed
        return field;
    }

    public Obect getCellEditorValue()
    {
        return (current == null ? null : current.getCellEditorValue());
    }

    public void cancelCellEditing()
    {
        if (current != null) current.cancelCellEditing();
    }

    public void addCellEditorListener(CellEditorListener l)
    {
        comboBox.addCellEditorListener(l);
        textField.addCellEditorListener(l);
        checkBox.addCellEditorListener(l);
    }

    // implement other methods similarly
}

[binayakumar patel]

Thanks, It is working fine.

I face one more problem that, when i click on Cell for edit,then the scope is remains their till i will not give enter , in the case of JTextField.
Similarly in JComboBox the Scope is remain there till if I will not select any value from JComboBox.

Is there any way that it will lose its scope when i will click on any other cell.

[Rob Camick]

Instead of putting all the code in a custom editor, override the getCellEditor(...) method of JTable to return the appropriate editor for the row and column.

[binayakumar patel]

Hi Rob,

I can not understand / follow your suggestion can you please define it more clearly.

[Rob Prime]

Rob Camick wrote:Instead of putting all the code in a custom editor, override the getCellEditor(...) method of JTable to return the appropriate editor for the row and column.

Uhm yeah, that would be better

Rob means this (which I used myself for a similar situation as well... why did I forget?):

class MyTable extends JTable
{
    @Override
    public TableCellEditor getCellEditor(int row, int column)
    {
        // determine whether to return a combo box editor, text field editor, check box editor, etc
        return super.getCellEditor(row, column); // if you can't determine what to return, return the default
    }
}