ActionListener on JButton in JTable header freezes application

Question

I have a JTable which uses a JButton for one of the headers on a column.

Without an ActionListener the button seems to function normally, I can see it visually click. However when I add in an ActionListener which should pop up a JOptionPane the application stops redrawing itself, stops responding to any actions, and doesn't draw the option pane.

public class ButtonHeaderRenderer extends JButton implements TableCellRenderer, ActionListener
{
    int pushedColumn;

    public ButtonHeaderRenderer(Icon image, JTableHeader header, ActionListener actionListener)
    {
        pushedColumn = -1;
        setIcon(image);
        setForeground(header.getForeground());
        setBackground(header.getBackground());
        setBorder(UIManager.getBorder("TableHeader.cellBorder"));
        setMargin(new Insets(0, 0, 0, 0));
        addActionListener(this);
    }

    @Override
    public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column)
    {
        setText((value == null) ? "" : value.toString());
        boolean isPressed = (column == pushedColumn);
        getModel().setPressed(isPressed);
        getModel().setArmed(isPressed);
        return this;
    }

    public void setPressedColumn(int col)
    {
        this.pushedColumn = col;
    }

    public void actionPerformed(ActionEvent e)
    {
        JOptionPane.showMessageDialog(null, "alert", "alert", JOptionPane.ERROR_MESSAGE);
    }
}

Does anyone know what might be causing the issue?

edit: It seems that creating a new thread in the actionPerformed method and creating the JOptionPane in that works. This seems like a hack however, I've used JOptionPane in other places and it works fine without starting a new thread.

Answer 1

Try to call the JOptionPane inside SwingUtilities.invokeLater()