change color JTable cells with getTableCellRendererComponent NOTHING HAPPENDS

Question

I am trying to change the color of some cells in my JTable. I have tried to override getTableCellRendererComponent in a simple example, and it works nice. But when I do the same in my project nothing changes...

I have my JPanel with my JTable in a Box like this:

boxTable=Box.createHorizontalBox();
box2Table.add(boxTable);

//JTable                    
tablaContador = new JTable(datosContador,cabeceraContador);

//MODIF COLOR
tablaContador.setDefaultRenderer(Object.class, new ColorRenderer());

Doing:

System.out.println(tablaContador.getColumnClass(3));

I can know that the first parameter of setDefaultRenderer is Object.class I don't know if the problem is here... i have only strings in the Table, but I have tried String.class and nothing happens

Then I modify some things of JTable's Cells:

tablaContador.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
boxTable.add(tablaContador);


//Align cells
for (int i=0; i<cabeceraContador.length;i++){
tablaContador.getColumnModel().getColumn(i).setCellRenderer(alinearCeldas);
                }

//Modify cells' width
tablaContador.getColumnModel().getColumn(0).setMinWidth(150);
for (int i=1; i<cabeceraContador.length;i++){
    tablaContador.getColumnModel().getColumn(i).setMaxWidth(40);
}

//Scroll for the Table
scrollContador=new JScrollPane(tablaContador,JScrollPane.VERTICAL_SCROLLBAR_NEVER,JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);

scrollContador.setPreferredSize(new Dimension(1000,80));
scrollContador.setMinimumSize(new Dimension(1000,80));
scrollContador.setMaximumSize(new Dimension(2000,80));

//Add scroll to the box         
box2Table.add(scrollContador);

And my ColorRenderer class is:

public class ColorRenderer extends DefaultTableCellRenderer{

    private Component c;

    @Override
    public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus,int row, int column) {

        c = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);


        c.setBackground(Color.BLUE);            


        return c;
    }


}

Table result

So It does not work in my project i don't know why

any idea?

thaks!

Answer 1

I see:

tablaContador.setDefaultRenderer(Object.class, new ColorRenderer());

and then I see:

for (int i=0; i<cabeceraContador.length;i++)
{
    tablaContador.getColumnModel().getColumn(i).setCellRenderer(alinearCeldas);
}

The assignment of the renderer to a specific column takes precedence over setting the default renderer so your color renderer is never used.

Not exactly what you are trying to do, but I would guess you need to add the color rendering logic to the alignment renderer. In other words all the rendering logic must be contained in a single renderer. You can't merge multiple renderers.

Here is a simple example of a custom renderer:

import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;

public class TableRenderer extends JPanel
{
    public TableRenderer()
    {
        String[] columnNames = {"String", "Integer"};
        Object[][] data =
        {
            {"A", new Integer(1)},
            {"B", new Integer(2)},
            {"C", new Integer(10)},
            {"D", new Integer(4)}
        };

        DefaultTableModel model = new DefaultTableModel(data, columnNames);
        JTable table = new JTable( model );
        table.setPreferredScrollableViewportSize(table.getPreferredSize());
        JScrollPane scrollPane = new JScrollPane( table );
        add( scrollPane );

        //  Override default renderer on a specific column

        TableCellRenderer colorRenderer = new ColorRenderer();
        table.getColumnModel().getColumn(1).setCellRenderer( colorRenderer );
    }

    /*
    **  Color the focused cell
    */
    class ColorRenderer extends DefaultTableCellRenderer
    {
        public ColorRenderer()
        {
            super();
            setHorizontalAlignment(JLabel.RIGHT);
        }

        @Override
        public Component getTableCellRendererComponent(
            JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column)
        {
            super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);

            if (isSelected)
                setBackground( table.getSelectionBackground() );
            else
            {
                setBackground( null );

                try
                {
                    int number = Integer.parseInt( value.toString() );

                    if (number > 9)
                        setBackground( Color.RED );
                }
                catch(Exception e) {}
            }

            return this;
        }
    }

    private static void createAndShowGUI()
    {
        JFrame frame = new JFrame("Color Renderer");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(new TableRenderer());
        frame.pack();
        frame.setLocationByPlatform( true );
        frame.setVisible( true );
    }

    public static void main(String[] args)
    {
        EventQueue.invokeLater( () -> createAndShowGUI() );
/*
        EventQueue.invokeLater(new Runnable()
        {
            public void run()
            {
                createAndShowGUI();
            }
        });
*/
    }
}