day22/MyMenuTest.java

/*
练习：打开文件，保存文件 

弹出的会话窗口

FileDialog openDialog=new FileDialog(f,"我要打开",FileDialog.LOAD);//第三个参数是加载
FileDialog saveDialog=new FileDialog(f,"我要打开",FileDialog.SAVE);//第三个参数是保存

*/
package mymenu;

import java.awt.*;
import java.awt.event.*;
import java.io.*;
public class MyMenuTest 
{
	private Frame f;
	private MenuBar bar;
	private Menu fileMenu;
	private MenuItem openItem,saveItem,quitItem;

	private FileDialog openDialog,saveDialog;

	private TextArea ta;

	private File file;

	MyMenuTest()
	{
		init();
	}

	public void init()
	{
		f=new Frame("我的电脑");
		f.setBounds(300,200,600,500);
		
		ta=new TextArea();
		f.add(ta);

		bar=new MenuBar();
		fileMenu=new Menu("文件");
		openItem=new MenuItem("打开");
		saveItem=new MenuItem("保存");
		quitItem=new MenuItem("退出");

		bar.add(fileMenu);
		fileMenu.add(openItem);
		fileMenu.add(saveItem);
		fileMenu.add(quitItem);	
		
		f.setMenuBar(bar);

		openDialog=new FileDialog(f,"我要打开",FileDialog.LOAD);
		saveDialog=new FileDialog(f,"我要保存",FileDialog.SAVE);

		myEvent();

		f.setVisible(true);
	}

	public void myEvent()
	{
		//打开本机中的文件到Frame中的组件TextArea中
		openItem.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent e)
			{
				openDialog.setVisible(true);//弹出的对话框要设置为可见
				String dirPath = openDialog.getDirectory();
				String fileName = openDialog.getFile();
				//System.out.println(dirPath+"---"+fileName);
				if (dirPath==null||fileName==null)
					return;
				ta.setText("");

				file = new File(dirPath,fileName);
				try
				{
					BufferedReader bufr = new BufferedReader(new FileReader(file));
					String line=null;
					while((line=bufr.readLine())!=null)
					{
						ta.append(line+"\r\n");
					}
					bufr.close();
				}
				catch (Exception ex)
				{
					throw new RuntimeException("读写失败");
				}

			}
		});
		//保存TextArea中的内容到本机文本中
		saveItem.addActionListener(new ActionListener()
		{	
			public void actionPerformed(ActionEvent e)
			{
				if(file==null)
				{
					saveDialog.setVisible(true);
					String dirPath=saveDialog.getDirectory();
					String fileName=saveDialog.getFile();
					if(dirPath==null||fileName==null)
						return;
					file=new File(dirPath,fileName);
				}
				try
				{
					BufferedWriter bufw = new BufferedWriter(new FileWriter(file));
					String text = ta.getText();
					bufw.write(text);
					bufw.close();
				}
				catch (Exception ex)
				{
					throw new RuntimeException("写入失败");
				}
			}
		});

		quitItem.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent e)
			{
				System.exit(0);
			}
		});
		f.addWindowListener(new WindowAdapter()
		{
			public void windowClosing(WindowEvent e)
			{
				System.exit(0);
			}
		});
	}


	public static void main(String[] args) 
	{
		new MyMenuTest();
	}
}