Multiple Buttons in JTable Headers: Listening for Mouse Clicks

Question

I am writing a table which has table headers that contain multiple buttons. For the header cells, I am using a custom cell renderer which extends JPanel. A JLabel and JButtons are added to the JPanel.
Unfortunately, the buttons do not do anything. (Clicking in the area of a button doesn't appear to have any effect; the button doesn't appear to be pressed.)
Looking through the archives, I read a suggestion that the way to solve this problem is to listen for mouse clicks on the table header and then determine whether the mouse clicks fall in the area of the button. However, I cannot seem to get coordinates for the button that match the coordinates I see for mouse clicks.
The coordinates for mouse clicks seem to be relative to the top left corner of the table header (which would match the specification for mouse listeners). I haven't figured out how to get corresponding coordinates for the button. The coordinates returned by JButton.getBounds() seem to be relative to the top left corner of the panel. I hoped I could just add those to the coordinates for the panel to get coordinates relative to the table header, but JPanel.getBounds() gives me negative numbers for x and y (?!?). JPanel.getLocation() gives me the same negative numbers. When I tried JPanel.getLocationOnScreen(), I get an IllegalComponentStateException:
Exception in thread "AWT-EventQueue-0" java.awt.IllegalComponentStateException: component must be showing on the screen to determine its location
Can someone tell me how to get coordinates for the button on the JTableHeader? Or is there an easier way to do this (some way to make the buttons actually work so I can just use an ActionListener like I normally would)?
Here is relevant code:
public class MyTableHeaderRenderer extends JPanel implements TableCellRenderer {
public MyTableHeaderRenderer() {
  setOpaque(true);
  // ... set colors...
  setBorder(UIManager.getBorder("TableHeader.cellBorder"));
  setLayout(new FlowLayout(FlowLayout.LEADING));
  setAlignmentY(Component.CENTER_ALIGNMENT);
public Component getTableCellRendererComponent(JTable table,
                                                 Object value,
                                                 boolean isSelected,
                                                 boolean hasFocus,
                                                 int row,
                                                 int column){
  if (table != null){
    removeAll();
    String valueString = (value == null) ? "" : value.toString();
    add(new JLabel(valueString));
    Insets zeroInsets = new Insets(0, 0, 0, 0);
    final JButton sortAscendingButton = new JButton("1");
    sortAscendingButton.setMargin(zeroInsets);
    table.getTableHeader().addMouseListener(new MouseAdapter(){
      public void mouseClicked(MouseEvent e) {
        Rectangle buttonBounds = sortAscendingButton.getBounds();
        Rectangle panelBounds = MyTableHeaderRenderer.this.getBounds();
        System.out.println(Revising based on (" + panelBounds.x + ", "
                           + panelBounds.y + ")...");
        buttonBounds.translate(panelBounds.x, panelBounds.y);
        if (buttonBounds.contains(e.getX(), e.getY())){  // The click was on this button.
          System.out.println("Calling sortAscending...");
          ((MyTableModel) table.getModel()).sortAscending(column);
        else{
          System.out.println("(" + e.getX() + ", " + e.getY() + ") is not within "
                             + sortAscendingButton.getBounds() + " [ revised to " + buttonBounds + "].");
    sortAscendingButton.setEnabled(true);
    add(sortAscendingButton);
    JButton button2 = new JButton("2");
    button2.setMargin(zeroInsets);
    add(button2);
    //etc
  return this;
}

Answer 1

I found a solution to this: It's the getHeaderRect method in class JTableHeader.
table.getTableHeader().addMouseListener(new MouseAdapter(){
  public void mouseClicked(MouseEvent e) {
    Rectangle panelBounds = table.getTableHeader().getHeaderRect(column);
    Rectangle buttonBounds = sortAscendingButton.getBounds();
    buttonBounds.translate(panelBounds.x, panelBounds.y);
    if (buttonBounds.contains(e.getX(), e.getY()) && processedEvents.add(e)){  // The click was on this button.
      ((MyTableModel) table.getModel()).sortAscending(column);
});