JTable header renderer

Question

I'm trying to make the background of my JTable header have a gradient.

This works fine using the code:

      String[] colName = new String[] { "#", "Location", "Name" ,"Source", "System", "Hits", "Current", "Time" };
        Object[][] products = new Object[][] { 

            };

        dtm = new DefaultTableModel(products, colName) { 
            @Override
            public boolean isCellEditable(int row, int column) {
               //all cells false
               return false;
            }  
        };

        table = new JTable( dtm );
        table.setRowHeight(32);
        table.getTableHeader().setReorderingAllowed(false);
        table.setDefaultRenderer(Object.class, new VisitorRenderer()); 
        table.setFont(new java.awt.Font("Tahoma", Font.PLAIN, 12));  

        table.getColumnModel().getColumn(0).setMinWidth(5);
        table.getColumnModel().getColumn(1).setMinWidth(50);
        table.getColumnModel().getColumn(2).setMinWidth(5);            
        table.getColumnModel().getColumn(3).setMinWidth(5);
        table.getColumnModel().getColumn(4).setMinWidth(5);
        table.getColumnModel().getColumn(5).setMinWidth(3);
        table.getColumnModel().getColumn(6).setMinWidth(230);
        table.getColumnModel().getColumn(7).setMinWidth(3);

final JTableHeader header = table.getTableHeader();
header.setPreferredSize(new Dimension(100, 37));

header.setDefaultRenderer(new DefaultTableCellHeaderRenderer() {
    private Object selectedColumn;

    @Override
     public void paintComponent(Graphics g) {
        super.paintComponent(g);

        Graphics2D g2d = (Graphics2D) g;
        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
            RenderingHints.VALUE_ANTIALIAS_ON);
        GradientPaint gp = new GradientPaint(0, 0,
            new java.awt.Color(237, 237, 237), 0, getHeight(),
            new java.awt.Color(222, 222, 222));
        g2d.setPaint(gp);
        g2d.fillRect(0, 0, getWidth(), getHeight());
    }                 

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

        if (selectedColumn == value) {
            rendererComponent.setBorder(BorderFactory.createCompoundBorder(rendererComponent.getBorder(), BorderFactory.createLineBorder(Color.red, 1)));
            rendererComponent.setHorizontalAlignment(SwingConstants.LEFT);
        } else {
            rendererComponent.setBorder(BorderFactory.createCompoundBorder(rendererComponent.getBorder(), BorderFactory.createEmptyBorder(0, 5, 0, 0)));
            rendererComponent.setHorizontalAlignment(SwingConstants.CENTER);
        }
        if (column == 0) {
            rendererComponent.setForeground(header.getForeground());
        } else {
            rendererComponent.setForeground(header.getForeground());
        }

        return rendererComponent;
    }
});

However for some reason all I cannot see my border and text, it seems like the text also got the gradient applied?

I'd like to have the text black and a colored border between my columns. Any ideas?

Answer 1

The class, sun.swing.table.DefaultTableCellHeaderRenderer, is not a good choice for this. Instead, obtain a reference and wrap it in your implementation of TableCellRenderer, as shown here. See also Darryl Burke's Default Table Header Cell Renderer.