Change the background color of a row in a JTable

Question

I have a JTable with 3 columns  I ve set the TableCellRenderer for all the 3 columns like this  maybe not very effective      for  int i   0  i  lt  3  i           myJTable getColumnModel   getColumn i  setCellRenderer renderer        The getTableCellRendererComponent   returns a Component with a random background color for each row  How could I change the background to an other random color while the program is running

User · Answer

This is basically as simple as repainting the table. I haven't found a way to selectively repaint just one row/column/cell however.

In this example, clicking on the button changes the background color for a row and then calls repaint.

public class TableTest {
    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        final Color[] rowColors = new Color[] {
                randomColor(), randomColor(), randomColor()
        };
        final JTable table = new JTable(3, 3);
        table.setDefaultRenderer(Object.class, new TableCellRenderer() {
            @Override
            public Component getTableCellRendererComponent(JTable table,
                    Object value, boolean isSelected, boolean hasFocus,
                    int row, int column) {
                JPanel pane = new JPanel();
                pane.setBackground(rowColors[row]);
                return pane;
            }
        });
        frame.setLayout(new BorderLayout());

        JButton btn = new JButton("Change row2's color");
        btn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                rowColors[1] = randomColor();
                table.repaint();
            }
        });

        frame.add(table, BorderLayout.NORTH);
        frame.add(btn, BorderLayout.SOUTH);
        frame.pack();
        frame.setVisible(true);
    }

    private static Color randomColor() {
        Random rnd = new Random();
        return new Color(rnd.nextInt(256),
                rnd.nextInt(256), rnd.nextInt(256));
    }
}

User · Answer

Resumee of Richard Fearn s answer   to make each second line gray   jTable setDefaultRenderer Object class  new DefaultTableCellRenderer          Override     public Component getTableCellRendererComponent JTable table  Object value  boolean isSelected  boolean hasFocus  int row  int column                final Component c   super getTableCellRendererComponent table  value  isSelected  hasFocus  row  column           c setBackground row   2    0   Color LIGHT GRAY   Color WHITE           return c

User · Answer

One way would be store the current colour for each row within the model  Here s a simple model that is fixed at 3 columns and 3 rows   static class MyTableModel extends DefaultTableModel        List lt Color gt  rowColours   Arrays asList          Color RED          Color GREEN          Color CYAN             public void setRowColour int row  Color c            rowColours set row  c           fireTableRowsUpdated row  row              public Color getRowColour int row            return rowColours get row               Override     public int getRowCount             return 3              Override     public int getColumnCount             return 3              Override     public Object getValueAt int row  int column            return String format   d  d   row  column             Note that setRowColour calls fireTableRowsUpdated  this will cause just that row of the table to be updated   The renderer can get the model from the table   static class MyTableCellRenderer extends DefaultTableCellRenderer         Override     public Component getTableCellRendererComponent JTable table  Object value  boolean isSelected  boolean hasFocus  int row  int column            MyTableModel model    MyTableModel  table getModel            Component c   super getTableCellRendererComponent table  value  isSelected  hasFocus  row  column           c setBackground model getRowColour row            return c            Changing a row s colour would be as simple as   model setRowColour 1  Color YELLOW

User · Answer

The other answers given here work well since you use the same renderer in every column   However  I tend to believe that generally when using a JTable you will have different types of data in each columm and therefore you won t be using the same renderer for each column  In these cases you may find the Table Row Rendering approach helpfull

User · Answer

The call to getTableCellRendererComponent      includes the value of the cell for which a renderer is sought    You can use that value to compute a color  If you re also using an AbstractTableModel  you can provide a value of arbitrary type to your renderer   Once you have a color  you can setBackground   on the component that you re returning

[java] Change the background color of a row in a JTable

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