MenuElementExample.java Source code

Introduction

Here is the source code for MenuElementExample.java

Source

/*
Java Swing, 2nd Edition
By Marc Loy, Robert Eckstein, Dave Wood, James Elliott, Brian Cole
ISBN: 0-596-00408-7
Publisher: O'Reilly 
*/
// MenuElementExample.java
// An example of the JPopupMenu in action.
//

import java.awt.Component;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.JCheckBoxMenuItem;
import javax.swing.JFrame;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;
import javax.swing.JSeparator;
import javax.swing.JSlider;
import javax.swing.MenuElement;
import javax.swing.MenuSelectionManager;
import javax.swing.border.CompoundBorder;
import javax.swing.border.EmptyBorder;
import javax.swing.border.TitledBorder;
import javax.swing.event.PopupMenuEvent;
import javax.swing.event.PopupMenuListener;

public class MenuElementExample extends JPanel {

    public JPopupMenu popup;

    SliderMenuItem slider;

    int theValue = 0;

    public MenuElementExample() {

        popup = new JPopupMenu();
        slider = new SliderMenuItem();

        popup.add(slider);
        popup.add(new JSeparator());

        JMenuItem ticks = new JCheckBoxMenuItem("Slider Tick Marks");
        ticks.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                slider.setPaintTicks(!slider.getPaintTicks());
            }
        });
        JMenuItem labels = new JCheckBoxMenuItem("Slider Labels");
        labels.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                slider.setPaintLabels(!slider.getPaintLabels());
            }
        });
        popup.add(ticks);
        popup.add(labels);
        popup.addPopupMenuListener(new PopupPrintListener());

        addMouseListener(new MousePopupListener());
    }

    // Inner class to check whether mouse events are the popup trigger
    class MousePopupListener extends MouseAdapter {
        public void mousePressed(MouseEvent e) {
            checkPopup(e);
        }

        public void mouseClicked(MouseEvent e) {
            checkPopup(e);
        }

        public void mouseReleased(MouseEvent e) {
            checkPopup(e);
        }

        private void checkPopup(MouseEvent e) {
            if (e.isPopupTrigger()) {
                popup.show(MenuElementExample.this, e.getX(), e.getY());
            }
        }
    }

    // Inner class to print information in response to popup events
    class PopupPrintListener implements PopupMenuListener {
        public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
        }

        public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {
            theValue = slider.getValue();
            System.out.println("The value is now " + theValue);
        }

        public void popupMenuCanceled(PopupMenuEvent e) {
            System.out.println("Popup menu is hidden!");
        }
    }

    public static void main(String s[]) {
        JFrame frame = new JFrame("Menu Element Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setContentPane(new MenuElementExample());
        frame.setSize(300, 300);
        frame.setVisible(true);
    }

    // Inner class that defines our special slider menu item
    class SliderMenuItem extends JSlider implements MenuElement {

        public SliderMenuItem() {
            setBorder(new CompoundBorder(new TitledBorder("Control"), new EmptyBorder(10, 10, 10, 10)));

            setMajorTickSpacing(20);
            setMinorTickSpacing(10);
        }

        public void processMouseEvent(MouseEvent e, MenuElement path[], MenuSelectionManager manager) {
        }

        public void processKeyEvent(KeyEvent e, MenuElement path[], MenuSelectionManager manager) {
        }

        public void menuSelectionChanged(boolean isIncluded) {
        }

        public MenuElement[] getSubElements() {
            return new MenuElement[0];
        }

        public Component getComponent() {
            return this;
        }
    }
}