Question

how can I prevent triggering and showing JPopupMenu only if is Mouse Cursor over selected JTable'Row

my question: if is there another way as getBounds from selected row and determine/compare that with Mouse position…

my simple sscce demonstrated just un-wanted opposite status, any row could be selected and JPopupMenu is triggered from whole JTable

import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;

public class TableCheckBox extends JFrame {

    private static final long serialVersionUID = 1L;
    private JTable table;

    public TableCheckBox() {
        Object[] columnNames = {"Type", "Company", "Shares", "Price", "Boolean"};
        Object[][] data = {
            {"Buy", "IBM", new Integer(1000), new Double(80.50), false},
            {"Sell", "MicroSoft", new Integer(2000), new Double(6.25), true},
            {"Sell", "Apple", new Integer(3000), new Double(7.35), true},
            {"Buy", "Nortel", new Integer(4000), new Double(20.00), false}
        };
        DefaultTableModel model = new DefaultTableModel(data, columnNames);
        table = new JTable(model) {

            private static final long serialVersionUID = 1L;

            @Override
            public Class getColumnClass(int column) {
                return getValueAt(0, column).getClass();
            }
        };
        table.setPreferredScrollableViewportSize(table.getPreferredSize());
        JScrollPane scrollPane = new JScrollPane(table);
        add(scrollPane);
        createPopupMenu();
    }

    private void createPopupMenu() {
        JPopupMenu popup = new JPopupMenu();
        JMenuItem myMenuItem1 = new JMenuItem("cccccccccccccccccccccc");
        JMenuItem myMenuItem2 = new JMenuItem("bbbbbbbbbbbbbbbbbbbbbb");
        popup.add(myMenuItem1);
        popup.add(myMenuItem2);
        MouseListener popupListener = new PopupListener(popup);
        table.addMouseListener(popupListener);
    }

    private class PopupListener extends MouseAdapter {

        private JPopupMenu popup;

        PopupListener(JPopupMenu popupMenu) {
            popup = popupMenu;
        }

        @Override
        public void mousePressed(MouseEvent e) {
            maybeShowPopup(e);
        }

        @Override
        public void mouseReleased(MouseEvent e) {
            if (table.getSelectedRow() != -1) {
                maybeShowPopup(e);
            }
        }

        private void maybeShowPopup(MouseEvent e) {
            if (e.isPopupTrigger()) {
                popup.show(e.getComponent(), e.getX(), e.getY());
            }
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                TableCheckBox frame = new TableCheckBox();
                frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
                frame.pack();
                frame.setLocation(150, 150);
                frame.setVisible(true);
            }
        });
    }
}

Answer 1

It’s an interesting question, because it highlights missing api on JComponent 🙂

As we all know, the recommended way to register popupMenus is to use the componentPopupMenu property. Related api is

 void setComponentPopupMenu(JPopupMenu);
 JPopupMenu getComponentPopupMenu();
 Point getPopupLocation(MouseEvent);

what is missing (and actually needed for this requirement) is

JPopupMenu getComponentPopupMenu(MouseEvent);

this lack is all the more annoying, as the getPopupLocation is called (by AWTEventHelper deep in the LAF) after getComponentPopup(). So there’s no leeway for a hack like storing the last mouse event which might have triggered the popup and then decide which/if to return popup. And returning null for the location will only result in showing it at the mouse location

The only (dirty) hack (around my utter reluctance to get my hands dirty with a MouseListener 😉 is to override getComponentPopup and decide there whether or not to return it based on current mouse position

    table = new JTable(model) {

        /** 
         * @inherited <p>
         */
        @Override
        public JPopupMenu getComponentPopupMenu() {
            Point p = getMousePosition();
            // mouse over table and valid row
            if (p != null && rowAtPoint(p) >= 0) {
                // condition for showing popup triggered by mouse
                if (isRowSelected(rowAtPoint(p))) {
                    return super.getComponentPopupMenu();
                } else {
                    return null;
                }
            }
            return super.getComponentPopupMenu();
        }

    };

the side-effect is that popup showing isn’t triggered by keyboard as long as the mouse is anywhere above the table, which might or not be a problem.