import java.awt.*; import java.awt.event.*; import javax.swing.JPopupMenu; import javax.swing.JMenu; import javax.swing.JMenuItem; import javax.swing.JCheckBoxMenuItem; import javax.swing.JRadioButtonMenuItem; import javax.swing.ButtonGroup; import javax.swing.JMenuBar; import javax.swing.KeyStroke; import javax.swing.ImageIcon; import javax.swing.JTextArea; import javax.swing.JScrollPane; import javax.swing.JFrame; /* * This class adds popup menus to MenuDemo. */ public class PopupMenuDemo extends JFrame implements ActionListener, ItemListener { JTextArea output; JScrollPane scrollPane; String newline = "\n"; JPopupMenu popup; public PopupMenuDemo() { JMenuBar menuBar; JMenu menu, submenu; JMenuItem menuItem; JRadioButtonMenuItem rbMenuItem; JCheckBoxMenuItem cbMenuItem; addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) { System.exit(0); } }); //Add regular components to the window, using the default BorderLayout. Container contentPane = getContentPane(); output = new JTextArea(5, 30); output.setEditable(false); scrollPane = new JScrollPane(output); contentPane.add(scrollPane, BorderLayout.CENTER); //Create the menu bar. menuBar = new JMenuBar(); setJMenuBar(menuBar); //Build the first menu. menu = new JMenu("A Menu"); menu.setMnemonic(KeyEvent.VK_A); menu.getAccessibleContext().setAccessibleDescription( "The only menu in this program that has menu items"); menuBar.add(menu); //a group of JMenuItems menuItem = new JMenuItem("A text-only menu item", KeyEvent.VK_T); //menuItem.setMnemonic(KeyEvent.VK_T); //used constructor instead menuItem.setAccelerator(KeyStroke.getKeyStroke( KeyEvent.VK_1, ActionEvent.ALT_MASK)); menuItem.getAccessibleContext().setAccessibleDescription( "This doesn't really do anything"); menuItem.addActionListener(this); menu.add(menuItem); menuItem = new JMenuItem("Both text and icon", new ImageIcon("images/middle.gif")); menuItem.setMnemonic(KeyEvent.VK_B); menuItem.addActionListener(this); menu.add(menuItem); menuItem = new JMenuItem(new ImageIcon("images/middle.gif")); menuItem.setMnemonic(KeyEvent.VK_D); menuItem.addActionListener(this); menu.add(menuItem); //a group of radio button menu items menu.addSeparator(); ButtonGroup group = new ButtonGroup(); rbMenuItem = new JRadioButtonMenuItem("A radio button menu item"); rbMenuItem.setSelected(true); rbMenuItem.setMnemonic(KeyEvent.VK_R); group.add(rbMenuItem); rbMenuItem.addActionListener(this); menu.add(rbMenuItem); rbMenuItem = new JRadioButtonMenuItem("Another one"); rbMenuItem.setMnemonic(KeyEvent.VK_O); group.add(rbMenuItem); rbMenuItem.addActionListener(this); menu.add(rbMenuItem); //a group of check box menu items menu.addSeparator(); cbMenuItem = new JCheckBoxMenuItem("A check box menu item"); cbMenuItem.setMnemonic(KeyEvent.VK_C); cbMenuItem.addItemListener(this); menu.add(cbMenuItem); cbMenuItem = new JCheckBoxMenuItem("Another one"); cbMenuItem.setMnemonic(KeyEvent.VK_H); cbMenuItem.addItemListener(this); menu.add(cbMenuItem); //a submenu menu.addSeparator(); submenu = new JMenu("A submenu"); submenu.setMnemonic(KeyEvent.VK_S); menuItem = new JMenuItem("An item in the submenu"); menuItem.setAccelerator(KeyStroke.getKeyStroke( KeyEvent.VK_2, ActionEvent.ALT_MASK)); menuItem.addActionListener(this); submenu.add(menuItem); menuItem = new JMenuItem("Another item"); menuItem.addActionListener(this); submenu.add(menuItem); menu.add(submenu); //Build second menu in the menu bar. menu = new JMenu("Another Menu"); menu.setMnemonic(KeyEvent.VK_N); menu.getAccessibleContext().setAccessibleDescription( "This menu does nothing"); menuBar.add(menu); //Create the popup menu. popup = new JPopupMenu(); menuItem = new JMenuItem("A popup menu item"); menuItem.addActionListener(this); popup.add(menuItem); menuItem = new JMenuItem("Another popup menu item"); menuItem.addActionListener(this); popup.add(menuItem); //Add listener to components that can bring up popup menus. MouseListener popupListener = new PopupListener(); output.addMouseListener(popupListener); scrollPane.addMouseListener(popupListener); menuBar.addMouseListener(popupListener); } public void actionPerformed(ActionEvent e) { JMenuItem source = (JMenuItem)(e.getSource()); String s = "Action event detected." + newline + " Event source: " + source.getText() + " (an instance of " + getClassName(source) + ")"; output.append(s + newline); } public void itemStateChanged(ItemEvent e) { JMenuItem source = (JMenuItem)(e.getSource()); String s = "Item event detected." + newline + " Event source: " + source.getText() + " (an instance of " + getClassName(source) + ")" + newline + " New state: " + ((e.getStateChange() == ItemEvent.SELECTED) ? "selected":"unselected"); output.append(s + newline); } // Returns just the class name -- no package info. protected String getClassName(Object o) { String classString = o.getClass().getName(); int dotIndex = classString.lastIndexOf("."); return classString.substring(dotIndex+1); } public static void main(String[] args) { PopupMenuDemo window = new PopupMenuDemo(); window.setTitle("PopupMenuDemo"); window.setSize(450, 260); window.setVisible(true); } class PopupListener extends MouseAdapter { public void mousePressed(MouseEvent e) { maybeShowPopup(e); } public void mouseReleased(MouseEvent e) { maybeShowPopup(e); } private void maybeShowPopup(MouseEvent e) { if (e.isPopupTrigger()) { popup.show(e.getComponent(), e.getX(), e.getY()); } } } }