Swing开发之JMenu篇

Swing菜单和菜单项是按钮，因为JMenuItem扩展AbstractButton，JMenu扩展JMenuItem。因此，Swing菜单和菜单项继承了如下功能，即包含文本和（或)图标、显示光标进入时的图标和助记符等。
　　JMenuItem和JMenu的父组件，它们最后都归于java.awt.Container，以强调菜单和菜单项都是容器。可以把任何类型的组件（从包含一个动画GIF的标签到JTree的一个实例）添加到一个菜单或菜单项中。
　　菜单和菜单项还实现MenuElement接口，以便参与菜单事件的处理。
　　工具条和弹出式菜单都扩展JComponent类，即任意组件都可以添加到一个工具条或弹出式菜单中。
　　本章将介绍下面的组件：
　　•JMenuItem
　　•JCheckBoxMenuItem
　　•JRadioButtonMenuItem
　　•JMenu
　　•JPopupMenu
　　•JMenuBar

例子 1：在菜单中增加复选菜单

import java.awt.event.KeyEvent; import javax.swing.JCheckBoxMenuItem; import javax.swing.JFrame; import javax.swing.JMenu; import javax.swing.JMenuBar; import javax.swing.JMenuItem; public class JCheckBoxMenuItemDemo { public static void main(final String args[]) { JFrame frame = new JFrame("MenuSample Example"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JMenuBar menuBar = new JMenuBar(); // File Menu, F - Mnemonic JMenu fileMenu = new JMenu("File"); fileMenu.setMnemonic(KeyEvent.VK_F); menuBar.add(fileMenu); // File->New, N - Mnemonic JMenuItem newMenuItem = new JMenuItem("New", KeyEvent.VK_N); fileMenu.add(newMenuItem); JCheckBoxMenuItem caseMenuItem = new JCheckBoxMenuItem("Case Sensitive"); caseMenuItem.setMnemonic(KeyEvent.VK_C); fileMenu.add(caseMenuItem); frame.setJMenuBar(menuBar); frame.setSize(350, 250); frame.setVisible(true); } }

例2：菜单事件处理

import java.awt.Container; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.ItemEvent; import java.awt.event.ItemListener; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import javax.swing.AbstractButton; import javax.swing.ButtonGroup; import javax.swing.JCheckBoxMenuItem; import javax.swing.JFrame; import javax.swing.JMenu; import javax.swing.JMenuBar; import javax.swing.JMenuItem; import javax.swing.JRadioButtonMenuItem; import javax.swing.JSeparator; import javax.swing.JTextField; public class SwingWinMenus extends JFrame { public static int WIDTH = 300; public static int HEIGHT = 300; public static String TITLE = "SwingWin"; Container frameContainer; JTextField textField = new JTextField(50); JMenuBar menuBar = new JMenuBar(); JMenu fileMenu = new JMenu("File"); JMenuItem fileNew = new JMenuItem("New"); JMenuItem fileOpen = new JMenuItem("Open"); JMenuItem fileSave = new JMenuItem("Save"); JMenuItem fileExit = new JMenuItem("Exit"); JMenu editMenu = new JMenu("Edit"); JMenuItem editCut = new JMenuItem("Cut"); JMenuItem editCopy = new JMenuItem("Copy"); JMenuItem editPaste = new JMenuItem("Paste"); JMenu specialMenu = new JMenu("Special"); JCheckBoxMenuItem specialCheck1 = new JCheckBoxMenuItem("Check 1"); JCheckBoxMenuItem specialCheck2 = new JCheckBoxMenuItem("Check 2", true); JSeparator separator = new JSeparator(); JRadioButtonMenuItem specialRadio1 = new JRadioButtonMenuItem("Radio 1"); JRadioButtonMenuItem specialRadio2 = new JRadioButtonMenuItem("Radio 2"); ButtonGroup buttonGroup = new ButtonGroup(); public SwingWinMenus() { super(""); fileMenu.add(fileNew); fileMenu.add(fileOpen); fileMenu.add(fileSave); fileMenu.add(fileExit); editMenu.add(editCut); editMenu.add(editCopy); editMenu.add(editPaste); specialMenu.add(specialCheck1); specialMenu.add(specialCheck2); specialMenu.add(separator); buttonGroup.add(specialRadio1); buttonGroup.add(specialRadio2); specialMenu.add(specialRadio1); specialMenu.add(specialRadio2); menuBar.add(fileMenu); menuBar.add(editMenu); menuBar.add(specialMenu); setJMenuBar(menuBar); frameContainer = getContentPane(); frameContainer.setLayout(null); textField.setBounds(100, 100, 100, 20); frameContainer.add(textField); setupEventHandlers(); setSize(450, 450); setVisible(true); } void setupEventHandlers() { addWindowListener(new WindowHandler()); fileNew.addActionListener(new MenuItemHandler()); fileOpen.addActionListener(new MenuItemHandler()); fileSave.addActionListener(new MenuItemHandler()); fileExit.addActionListener(new MenuItemHandler()); editCut.addActionListener(new MenuItemHandler()); editCopy.addActionListener(new MenuItemHandler()); editPaste.addActionListener(new MenuItemHandler()); specialCheck1.addItemListener(new ItemHandler()); specialCheck2.addItemListener(new ItemHandler()); specialRadio1.addItemListener(new ItemHandler()); specialRadio2.addItemListener(new ItemHandler()); } public static void main(String[] args) { SwingWinMenus app = new SwingWinMenus(); } public class WindowHandler extends WindowAdapter { public void windowClosing(WindowEvent e) { System.exit(0); } } public class MenuItemHandler implements ActionListener { public void actionPerformed(ActionEvent e) { String cmd = e.getActionCommand(); if (cmd.equals("Exit")) System.exit(0); else textField.setText(cmd); } } public class ItemHandler implements ItemListener { public void itemStateChanged(ItemEvent e) { AbstractButton button = (AbstractButton) e.getItem(); String label = button.getText(); if (button.isSelected()) label += " true"; else label += " false"; textField.setText(label); } } }

例3：弹出试菜单

import java.awt.Dimension; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JMenuItem; import javax.swing.JPopupMenu; import javax.swing.event.PopupMenuEvent; import javax.swing.event.PopupMenuListener; // Define PopupMenuListener class MyPopupMenuListener implements PopupMenuListener { public void popupMenuCanceled(PopupMenuEvent popupMenuEvent) { System.out.println("Canceled"); } public void popupMenuWillBecomeInvisible(PopupMenuEvent popupMenuEvent) { System.out.println("Becoming Invisible"); } public void popupMenuWillBecomeVisible(PopupMenuEvent popupMenuEvent) { System.out.println("Becoming Visible"); } } public class PopupMenuListenerDemo { public static void main(final String args[]) { JFrame frame = new JFrame("PopupSample Example"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // Create popup menu, attach popup menu listener JPopupMenu popupMenu = new JPopupMenu("Title"); popupMenu.setSize(new Dimension(100,50)); PopupMenuListener popupMenuListener = new MyPopupMenuListener(); popupMenu.addPopupMenuListener(popupMenuListener); // Cut JMenuItem cutMenuItem = new JMenuItem("Cut"); popupMenu.add(cutMenuItem); // Copy JMenuItem copyMenuItem = new JMenuItem("Copy"); popupMenu.add(copyMenuItem); // Paste JMenuItem pasteMenuItem = new JMenuItem("Paste"); pasteMenuItem.setEnabled(false); popupMenu.add(pasteMenuItem); // Separator popupMenu.addSeparator(); // Find JMenuItem findMenuItem = new JMenuItem("Find"); popupMenu.add(findMenuItem); JButton label = new JButton(); frame.add(label); label.setComponentPopupMenu(popupMenu); frame.setSize(350, 250); frame.setVisible(true); } }

例 4：给菜单增加快捷方式

import java.awt.event.KeyEvent; import javax.swing.JFrame; import javax.swing.JMenu; import javax.swing.JMenuBar; import javax.swing.JMenuItem; import javax.swing.KeyStroke; public class JMenuItemKeyStroke { public static void main(final String args[]) { JFrame frame = new JFrame("MenuSample Example"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JMenuBar menuBar = new JMenuBar(); // File Menu, F - Mnemonic JMenu fileMenu = new JMenu("File"); fileMenu.setMnemonic(KeyEvent.VK_F); menuBar.add(fileMenu); // File->New, N - Mnemonic JMenuItem newMenuItem = new JMenuItem("New", KeyEvent.VK_N); fileMenu.add(newMenuItem); // Edit->Cut, T - Mnemonic, CTRL-X - Accelerator JMenuItem cutMenuItem = new JMenuItem("Cut", KeyEvent.VK_T); KeyStroke ctrlXKeyStroke = KeyStroke.getKeyStroke("control X"); cutMenuItem.setAccelerator(ctrlXKeyStroke); fileMenu.add(cutMenuItem); frame.setJMenuBar(menuBar); frame.setSize(350, 250); frame.setVisible(true); } }