JTable text alignment issues when using JPanel as custom TableCellRenderer

Question

Hi there,
I'm having some difficulty with text alignment/border issues when using a custom TableCellRenderer. I'm using a JPanel with GroupLayout (although I've also tried others like FlowLayout), and I can't seem to get label text within the JPanel to align properly with the other cells in the table. The text inside my 'panel' cell is shifted downward. If I use the code from the DefaultTableCellRenderer to set the border when the cell receives focus, the problem gets worse as the text shifts when the new border is applied to the panel upon cell selection. Here's an SSCCE to demonstrate:
import java.awt.Color;
import java.awt.Component;
import java.awt.EventQueue;
import javax.swing.GroupLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTable;
import javax.swing.border.Border;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumn;
import sun.swing.DefaultLookup;
public class TableCellPanelTest extends JFrame {
  private class PanelRenderer extends JPanel implements TableCellRenderer {
    private JLabel label = new JLabel();
    public PanelRenderer() {
      GroupLayout layout = new GroupLayout(this);
      layout.setHorizontalGroup(layout.createParallelGroup().addComponent(label));
      layout.setVerticalGroup(layout.createParallelGroup().addComponent(label));
      setLayout(layout);
    public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
      if (isSelected) {
        setBackground(table.getSelectionBackground());
      } else {
        setBackground(table.getBackground());
      // Border section taken from DefaultTableCellRenderer
      if (hasFocus) {
        Border border = null;
        if (isSelected) {
          border = DefaultLookup.getBorder(this, ui, "Table.focusSelectedCellHighlightBorder");
        if (border == null) {
          border = DefaultLookup.getBorder(this, ui, "Table.focusCellHighlightBorder");
        setBorder(border);
        if (!isSelected && table.isCellEditable(row, column)) {
          Color col;
          col = DefaultLookup.getColor(this, ui, "Table.focusCellForeground");
          if (col != null) {
            super.setForeground(col);
          col = DefaultLookup.getColor(this, ui, "Table.focusCellBackground");
          if (col != null) {
            super.setBackground(col);
      } else {
        setBorder(null /*getNoFocusBorder()*/);
      // Set up our label
      label.setText(value.toString());
      label.setFont(table.getFont());
      return this;
  public TableCellPanelTest() {
    JTable table = new JTable(new Integer[][]{{1, 2, 3}, {4, 5, 6}}, new String[]{"A", "B", "C"});
    // set up a custom renderer on the first column
    TableColumn firstColumn = table.getColumnModel().getColumn(0);
    firstColumn.setCellRenderer(new PanelRenderer());
    getContentPane().add(table);
    pack();
  public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
      public void run() {
        new TableCellPanelTest().setVisible(true);
}There are basically two problems:
1) When first run, the text in the custom renderer column is shifted downward slightly.
2) Once a cell in the column is selected, it shifts down even farther.
I'd really appreciate any help in figuring out what's up!
Thanks!

Answer 1

1) LayoutManagers need to take the border into account so the label is placed at (1,1) while labels just start at (0,0) of the cell rect. Also the layout manager tend not to shrink component below their minimum size. Setting the labels minimum size to (0,0) seems to get the same effect in your example. Doing the same for maximum size helps if you set the row height for the JTable larger. Easier might be to use BorderLayout which ignores min/max for center (and min/max height for west/east, etc).
2) DefaultTableCellRenderer uses a 1px border if the UI no focus border is null, you don't.
3) Include a setDefaultCloseOperation is a SSCCE please. I think I've got a hunderd test programs running now :P.