swing13_16.java

java 简单的java源码

/**
 * ClassName: Swing13_16.class
 * Description: 对话框
 * Copyright:    Copyright (c) 2002
 * Company: 中国青年出版社
 * @author: Hong Yi
 * @version 1.0
 */

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

class MyFrame extends JFrame
	implements ActionListener
{
	public MyFrame()
    {
	    setTitle("Swing示例程序16");
	    setSize(300, 200);
	    setLocation(100,100);
        addWindowListener(new WindowAdapter()
        {
			public void windowClosing(WindowEvent e)
            {  System.exit(0);
            }
         });

         myPanel = new MyPanel();
         getContentPane().add(myPanel, "Center");

		 //新建一个菜单栏
		 JMenuBar menuBar = new JMenuBar();
		 setJMenuBar(menuBar);

		 JMenu dlgMenu = new JMenu("ShowDlg");
		 dlgMenu.setMnemonic('S');
		 //添加一个菜单项
		 JMenuItem dlgItem = new JMenuItem("MessageDlg", 'M');
		 dlgMenu.add(dlgItem);
		 dlgItem.addActionListener(this);
		 dlgItem = new JMenuItem("ConfirmDlg", 'C');
		 dlgMenu.add(dlgItem);
		 dlgItem.addActionListener(this);
		 dlgItem = new JMenuItem("OptionDlg", 'O');
		 dlgMenu.add(dlgItem);
		 dlgItem.addActionListener(this);
		 dlgItem = new JMenuItem("InputDlg", 'I');
		 dlgMenu.add(dlgItem);
		 dlgItem.addActionListener(this);

		 menuBar.add(dlgMenu);
	 }

		public void actionPerformed(ActionEvent evt)
		{
			if (evt.getSource() instanceof JMenuItem)
				//判断事件源是否为菜单项
			{
String itemName = evt.getActionCommand();
if (itemName.equals("MessageDlg"))
{
	 JOptionPane.showMessageDialog(this,
			"You've got a message!",
			"Message Dlg",
			JOptionPane.INFORMATION_MESSAGE);
}
else if (itemName.equals("ConfirmDlg"))
{
	JOptionPane.showConfirmDialog(this,
			"You need to be confirmed!",
		   "Confirm Dlg",
		   JOptionPane.YES_NO_CANCEL_OPTION,
		   JOptionPane.INFORMATION_MESSAGE);
}
else if (itemName.equals("OptionDlg"))
{
	Object[] options = { "China", "USA", "Japan" };
	JOptionPane.showOptionDialog(this,
			"You need to select an option!",
			"Option Dlg",
			JOptionPane.DEFAULT_OPTION,
			JOptionPane.WARNING_MESSAGE,
			null, options, options[1]);

}
else if (itemName.equals("InputDlg"))
{
	String inputValue = JOptionPane.showInputDialog("Please input a value");
	myPanel.setMsg(inputValue);
}
			}
		}

 	 private MyPanel myPanel;
}

class MyPanel extends JPanel
{
	public MyPanel()
	{
		szShowMsg = "";
	}

	public void setMsg(String szMsg)
	{
		szShowMsg = szMsg;
		repaint();
	}

	//绘制信息
	public void paintComponent(Graphics g)
    {
 	    super.paintComponent(g);
		g.drawString(szShowMsg, 20, 20);
   }

   private String szShowMsg;

}

public class Swing13_16
{
	public static void main(String[] args)
    {
		JFrame frame = new MyFrame();
        frame.setVisible(true);
    }
}