Java JPopupMenu computePopupLocation(MouseEvent event, Component rel, JPopupMenu popup)

Description

Swing 1.0 and 1.1 have a horrible bug with respect to popup menus.

License

Open Source License

Declaration

static public Point computePopupLocation(MouseEvent event,
        Component rel, JPopupMenu popup) 

Method Source Code

//package com.java2s;
/*/*from  w  ww .  jav  a  2s  .c  o  m*/
 ** Tim Endres' utilities package.
 ** Copyright (c) 1997 by Tim Endres
 **
 ** This program is free software.
 **
 ** You may redistribute it and/or modify it under the terms of the GNU
 ** General Public License as published by the Free Software Foundation.
 ** Version 2 of the license should be included with this distribution in
 ** the file LICENSE, as well as License.html. If the license is not
 ** included with this distribution, you may find a copy at the FSF web
 ** site at 'www.gnu.org' or 'www.fsf.org', or you may write to the
 ** Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139 USA.
 **
 ** THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY OF ANY KIND,
 ** NOT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY. THE AUTHOR
 ** OF THIS SOFTWARE, ASSUMES _NO_ RESPONSIBILITY FOR ANY
 ** CONSEQUENCE RESULTING FROM THE USE, MODIFICATION, OR
 ** REDISTRIBUTION OF THIS SOFTWARE.
 **
 */

import java.awt.Component;
import java.awt.Dimension;
import java.awt.Point;
import java.awt.Toolkit;
import java.awt.event.MouseEvent;
import javax.swing.JPopupMenu;

public class Main {
    /**
     * Swing 1.0 and 1.1 have a horrible bug with respect to popup menus.
     * Namely that they are not adjusted to be kept on-screen.
     * Here, we ensure that the popup is properly located.
     * This method will continue to work even after Sun fixes Swing...
     * However, because there is a case where we estimate the size of
     * the popup menu, one could make the argument to noop this method
     * when the bug is finally fixed.
     */

    static public Point computePopupLocation(MouseEvent event,
            Component rel, JPopupMenu popup) {
        Dimension psz = popup.getSize();
        Dimension ssz = Toolkit.getDefaultToolkit().getScreenSize();
        Point gLoc = rel.getLocationOnScreen();
        Point result = new Point(event.getX(), event.getY());

        gLoc.x += event.getX();
        gLoc.y += event.getY();

        if (psz.width == 0 || psz.height == 0) {
            // DRAT! Now we need to "estimate"...
            int items = popup.getSubElements().length;
            psz.height = (items * 22);
            psz.width = 100;
        }

        psz.height += 5;

        if ((gLoc.x + psz.width) > ssz.width) {
            result.x -= ((gLoc.x + psz.width) - ssz.width);
            if ((gLoc.x + result.x) < 0)
                result.x = -(gLoc.x + event.getX());
        }

        if ((gLoc.y + psz.height) > ssz.height) {
            result.y -= ((gLoc.y + psz.height) - ssz.height);
            if ((gLoc.y + result.y) < 0)
                result.y = -gLoc.y;
        }

        return result;
    }
}

Related

1. addSeparatorIfNecessary(JPopupMenu popup)
2. addSeparatorIfNeeded(JPopupMenu popupMenu)
3. applyDefaultProperties(final JPopupMenu comp)
4. attachPopupMenu(final JComponent component, final JPopupMenu popupMenu)
5. cleanPopupLayoutMetrics(JPopupMenu popupMenu)
6. createPopupMenu()
7. createPopupMenu(String menuText, JPopupMenu menu, ActionListener listener)
8. ensurePopupIsOnScreen(JPopupMenu popup)
9. findMenuComponent(JPopupMenu menu, String menuComponentName)