//目前实现了可以将文本内容读入到文本区并显示的功能
//问题一:在运行程序时,会有异常信息一闪而过.
package Notepad_new;

import javax.swing.*;
import java.awt.*;
import java.awt.Event.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.*;

public class NotePad{
    public static void main(String args[]){
        try{
            JFrame frame = new NoteFrame();
        
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        }catch(Exception e){
            System.out.println(e.toString());
        }
        
    }
}
class NoteFrame extends JFrame{

    public NoteFrame(){
        
        setSize(400,600);
        Container c = getContentPane();
        TextPanel p = new TextPanel();
        area = p.area;
        JScrollPane scroll = new JScrollPane(area);
        p.add(scroll);
        add(p);
        
        
        JMenuBar menubar = new JMenuBar();
        this.setJMenuBar(menubar);
        JMenu fileMenu = new JMenu("文件");
        JMenuItem openItem = new JMenuItem("打开");
        openItem.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                JFileChooser chooser = new JFileChooser();
                chooser.setCurrentDirectory(new File("."));
                chooser.showOpenDialog(NoteFrame.this);
                fileName = chooser.getSelectedFile().getPath();
                try{
                    File f = new File(fileName);
                    BufferedInputStream in = new BufferedInputStream(new FileInputStream(f));
                    int n = in.available();
                    byte[] b = new byte[n];
                    in.read(b,0,n);
                    fileText = new String(b);
                    area.setText(fileText);
                }catch(IOException e1){
                    System.out.println(e.toString());
                }
            }
        });
        fileMenu.add(openItem);
        JMenuItem exitItem = new JMenuItem("退出");
        exitItem.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                System.exit(0);
            }
        });
        fileMenu.add(exitItem);
        menubar.add(fileMenu);
        pack();
        area.setText(fileText);
    }
    
    public static String fileText,fileName;
    public static JTextArea area;
}
class TextPanel extends JPanel{
    public TextPanel(){
        setSize(400,400);
        area = new JTextArea(20,20);
        BorderLayout layout = new BorderLayout();
        this.setLayout(layout);
        add(area,layout.CENTER);
    }
    public  static JTextArea area;
}