//MenuExample.java

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

public class MenuExample
{
	public static void main(String[] args)
	{  
		MenuFrame frame = new MenuFrame();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.show();
	}
}

class MenuFrame extends JFrame
{  
	public MenuFrame()
	{  
		setTitle("MenuExample");
		setSize(WIDTH, HEIGHT);

		Container contentPane = getContentPane();
		JPanel textPanel=new JPanel();

		//創建顯示菜單操作的文本區
		myTextField = new JTextField("", 20);
		textPanel.add(myTextField);
		contentPane.add(textPanel);
		
		//創建菜單欄，并將菜單欄加入到框架中
		JMenuBar menuBar = new JMenuBar();
		setJMenuBar(menuBar);

		//創建菜單及菜單項，并添加快捷鍵和加速器
		//“File”菜單
		JMenu fileMenu = new JMenu("File");
		//設置菜單的快捷鍵
		fileMenu.setMnemonic('F'); 

		//新建“New”菜單項，并添加共用的事件監聽器
		newItem = fileMenu.add(new ShowAction("New"));
		//設置菜單項的加速器
		newItem.setAccelerator(KeyStroke.getKeyStroke(
			KeyEvent.VK_N, InputEvent.CTRL_MASK));
		//新建“Open”菜單項和監聽器
		openItem = fileMenu.add(new ShowAction("Open"));
		openItem.setAccelerator(KeyStroke.getKeyStroke(
			KeyEvent.VK_O, InputEvent.CTRL_MASK));
		//增加分隔線
		fileMenu.addSeparator();
		//新建“Save”菜單項和監聽器
		saveItem = fileMenu.add(new ShowAction("Save"));
		saveItem.setAccelerator(KeyStroke.getKeyStroke(
			KeyEvent.VK_S, InputEvent.CTRL_MASK));
		//初始設置“Save”菜單項為禁用狀態
		saveItem.setEnabled(false);
		//新建“Close”菜單項和監聽器
		closeItem = fileMenu.add(new ShowAction("Close"));
		closeItem.setAccelerator(KeyStroke.getKeyStroke(
			KeyEvent.VK_L, InputEvent.CTRL_MASK));
		closeItem.setEnabled(false);
		fileMenu.addSeparator();
		//新建“Exit”菜單項和監聽器
		JMenuItem exitItem = new JMenuItem("Exit", 'T');
		exitItem.addActionListener(new AbstractAction("Exit")
			{
				public void actionPerformed(ActionEvent event)
				{
					System.exit(0);
				}
			});
		exitItem.setAccelerator(KeyStroke.getKeyStroke(
			KeyEvent.VK_T, InputEvent.CTRL_MASK));
 		fileMenu.add(exitItem);

		//“Edit”菜單
		JMenu editMenu = new JMenu("Edit");
		//設置菜單的快捷鍵
		editMenu.setMnemonic('E'); 

		//新建“Cut”菜單項和監聽器
		cutItem = new JMenuItem("Cut", 'C');
		editMenu.add(cutItem);
		//添加事件監聽器
		cutItem.addActionListener(new ShowAction("Cut"));
		cutItem.setAccelerator(KeyStroke.getKeyStroke(
			KeyEvent.VK_U, InputEvent.CTRL_MASK));
		cutItem.setEnabled(false);
		//新建“Copy”菜單項和監聽器
		copyItem = new  JMenuItem("Copy", 'Y');
		copyItem.addActionListener(new ShowAction("Copy"));
		copyItem.setAccelerator(KeyStroke.getKeyStroke(
			KeyEvent.VK_Y, InputEvent.CTRL_MASK));
		copyItem.setEnabled(false);
		//新建“Paste”菜單項和監聽器
		pasteItem = new JMenuItem("Paste", 'P');
		pasteItem.addActionListener(new ShowAction("Paste"));
		pasteItem.setAccelerator(KeyStroke.getKeyStroke(
			KeyEvent.VK_P, InputEvent.CTRL_MASK));
		pasteItem.setEnabled(false);
		
		editMenu.add(copyItem);
		editMenu.add(pasteItem);

		//“Search”菜單
		JMenu searchMenu = new JMenu("Search");
		searchMenu.setMnemonic('S'); 

		//創建單選按鈕菜單項“Forward”和“Backward”
		ButtonGroup group = new ButtonGroup();
		forwardItem = new JRadioButtonMenuItem("Forward");
		forwardItem.addActionListener(new ShowAction("Forward"));
		forwardItem.setSelected(true);
		forwardItem.setEnabled(false);

		backwardItem = new JRadioButtonMenuItem("Backward");
		backwardItem.addActionListener(new ShowAction("Backward"));
		backwardItem.setEnabled(false);

		group.add(forwardItem);
		group.add(backwardItem);
		searchMenu.add(forwardItem);
		searchMenu.add(backwardItem);

		//"View"菜單
		JMenu viewMenu = new JMenu("View");
		viewMenu.setMnemonic('V'); 
		//創建子菜單
		JMenu optionMenu = new JMenu("Option");
		optionMenu.setMnemonic('O'); 
		//創建復選框菜單項“ToolBar”和“Status”
		JCheckBoxMenuItem toolItem = new JCheckBoxMenuItem("ToolBar");
		JCheckBoxMenuItem statusItem = new JCheckBoxMenuItem("Status");
		toolItem.addActionListener(new ShowAction("ToolBar"));
		statusItem.addActionListener(new ShowAction("Status"));
		//將菜單項添加到子菜單中
		optionMenu.add(toolItem);
		optionMenu.add(statusItem);
		//將子菜單添加到“View”菜單中
		viewMenu.add(optionMenu);

		//將菜單加入到菜單欄中
		menuBar.add(fileMenu);
		menuBar.add(editMenu);
		menuBar.add(searchMenu);
		menuBar.add(viewMenu);
		
		//彈出式菜單
		popup = new JPopupMenu();
		
		//新建彈出式菜單中的“Cut”菜單項和監聽器
		cutItemPop = new JMenuItem("Cut", 'C');
		cutItemPop.addActionListener(new ShowAction("CutPop"));
		cutItemPop.setEnabled(false);
		
		//新建彈出式菜單中的“Copy”菜單項和監聽器
		copyItemPop = new  JMenuItem("Copy", 'Y');
		copyItemPop.addActionListener(new ShowAction("CopyPop"));
		copyItemPop.setEnabled(false);
		
		//新建彈出式菜單中的“Paste”菜單項和監聽器
		pasteItemPop = new JMenuItem("Paste", 'P');
		pasteItemPop.addActionListener(new ShowAction("PastePop"));
		pasteItemPop.setEnabled(false);

		popup.add(cutItemPop);
		popup.add(copyItemPop);
		popup.add(pasteItemPop);
		
		//實現彈出式菜單的彈出觸發器
		getContentPane().addMouseListener(new MouseAdapter()
			{  
				public void mouseReleased(MouseEvent event)         
				{  
					if (event.isPopupTrigger())
						//指定彈出式菜單的父組件以及顯示位置
						popup.show(event.getComponent(),
							event.getX(), event.getY());
				}
			});
	}

	//菜單項的共用事件監聽器
	private class ShowAction extends AbstractAction
	{  
		public ShowAction(String name) { super(name); }
		public void actionPerformed(ActionEvent event)
		{  
			//實現菜單項的啟用和禁用控制
			if (event.getSource() == newItem || 
				event.getSource() == openItem)
			{
				saveItem.setEnabled(true);
				closeItem.setEnabled(true);
				cutItem.setEnabled(true);
				copyItem.setEnabled(true);
				pasteItem.setEnabled(true);
				forwardItem.setEnabled(true);
				backwardItem.setEnabled(true);
				cutItemPop.setEnabled(true);
				copyItemPop.setEnabled(true);
				pasteItemPop.setEnabled(true);
			}
			if (event.getSource() == closeItem)
			{
				saveItem.setEnabled(false);
				closeItem.setEnabled(false);
				cutItem.setEnabled(false);
				copyItem.setEnabled(false);
				pasteItem.setEnabled(false);
				forwardItem.setEnabled(false);
				backwardItem.setEnabled(false);
				cutItemPop.setEnabled(false);
				copyItemPop.setEnabled(false);
				pasteItemPop.setEnabled(false);
			}
			//在文本域中顯示菜單選擇結果
			myTextField.setText(getValue(Action.NAME)+ " selected.");
		}
	}

	public static final int WIDTH = 250;
	public static final int HEIGHT = 200;  

	private JMenuItem newItem;
	private JMenuItem openItem;
	private JMenuItem closeItem;
	private JMenuItem saveItem;
	private JMenuItem cutItem;
	private JMenuItem copyItem;
	private JMenuItem pasteItem;
	private JMenuItem cutItemPop;
	private JMenuItem copyItemPop;
	private JMenuItem pasteItemPop;
	private JRadioButtonMenuItem  forwardItem;
	private JRadioButtonMenuItem  backwardItem;
	
	private JPopupMenu popup;
	private JTextField myTextField;
}