textviewer.java

java编程开发技巧与实例的编译测试通过的所有例程

import java.awt.*;
import java.awt.event.*;
import java.io.*;

public class TextViewer extends Frame implements ActionListener
{
	private Menu fileMenu	=	new Menu("File");
	private MenuItem fileOpen	=	new MenuItem("Open");
	private MenuItem fileExit	=	new MenuItem("Exit");
	private TextArea text		=	new TextArea();
	
	public TextViewer()
	{
		super("Text Viewer");
		fileMenu.add(fileOpen);
		fileOpen.addActionListener(this);
		fileMenu.addSeparator();
		fileMenu.add(fileExit);
		fileExit.addActionListener(this);
		MenuBar menu	=	new MenuBar();
		menu.add(fileMenu);
		setMenuBar(menu);
		setLayout(new BorderLayout());
		add("Center", text);
		text.setEditable(false);
		setSize(400, 400);
		setLocationRelativeTo(this);
		setVisible(true);
	}
	public void readFile(String file)
	{
		text.setText("");
		try
		{
			BufferedReader in	=	new BufferedReader(new FileReader(file));
			String line;
			while	((line = in.readLine()) != null)
				text.append(line + "\n");
			in.close();
			text.setCaretPosition(0);
		}
		catch	(IOException ioe)
		{
			System.err.println(ioe);
		}
	}
	public void actionPerformed(ActionEvent ae)
	{
		if (ae.getSource() == fileExit)
			System.exit(0);
		else if (ae.getSource() == fileOpen)
		{
			FileDialog fd	=	new FileDialog(this, "Open File", FileDialog.LOAD);
			fd.setVisible(true);
			if (fd.getFile() != null)
			{
				File file	=	new File(fd.getDirectory() + fd.getFile());
				if (file.exists())
					readFile(file.toString());
				else
					text.setText("File Name:" + file + " invalid.");
			}
			fd.dispose();
		}
	}
	public static void main(String args[])
	{
		TextViewer editor	=	new TextViewer();
	}
}