notepad.java

基本实现了记事本的所有功能

//郑世杰  200631500155  计科5班
import java.io.*;
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;
import javax.swing.filechooser.*;
import javax.swing.event.*;
import java.math.*;
import java.awt.image.BufferedImage;
import java.awt.Toolkit;

public class NotePad extends JFrame implements ActionListener,ItemListener{

	 JButton b_save,b_close;
	 JTextArea textArea;
	 boolean isCurrentFileExists=false;
	 File tempFile;
	 JPanel jp;
	 JMenu file,edit,style,help;
	 JCheckBoxMenuItem s_autoLine;
	 JMenuItem f_new,f_open,f_save,f_close,f_saveas,e_copy,e_paste,e_cut,e_clear,e_selectAll,s_font,s_color,h_editor;
	 JMenuBar jmb;
	 JScrollPane jsp;
	 JPopupMenu popUpMenu=new JPopupMenu();
	 JLabel stateBar;
	 JLabel j1,jstate;
	 JFileChooser jfc=new JFileChooser();
	 JMenuItem je_copy,je_paste,je_cut,je_clear,je_selectAll;

	 public NotePad()          //构造函数，初始化
	 {
	  jp = new JPanel();
//	  j1 = new JLabel("JAVA记事本");
//	  jstate = new JLabel("状态栏:");
	  jmb = new JMenuBar();                        //初始化菜单栏
	  textArea = new JTextArea();                  //初始化编辑窗口
	  jsp = new JScrollPane(textArea);
	  file = new JMenu("File");
	  edit = new JMenu("Edit");
	  style = new JMenu("Style");
	  help = new JMenu("SOS");

	  je_copy=new JMenuItem("Copy");
	  je_paste=new JMenuItem("Paste");
	  je_cut=new JMenuItem("Cut");
	  je_clear=new JMenuItem("Clear");
	  je_selectAll=new JMenuItem("SelectAll");

	  je_copy.addActionListener(this);
	  je_paste.addActionListener(this);
	  je_cut.addActionListener(this);
	  je_clear.addActionListener(this);
	  je_selectAll.addActionListener(this);

	  f_new = new JMenuItem("New");
	  f_new.addActionListener(this);

	  f_open = new JMenuItem("Open");
	  f_open.addActionListener(this);

	  f_save = new JMenuItem("Save");
	  f_save.addActionListener(this);

	  f_saveas = new JMenuItem("Save as");
	  f_saveas.addActionListener(this);

	  f_close = new JMenuItem("Close");
	  f_close.addActionListener(this);

	  e_copy = new JMenuItem("Copy");
	  e_copy.addActionListener(this);

	  e_paste = new JMenuItem("Paste");
	  e_paste.addActionListener(this);

	  e_cut = new JMenuItem("Cut");
	  e_cut.addActionListener(this);

	  e_clear=new JMenuItem("Clear");
	  e_clear.addActionListener(this);

     e_selectAll=new JMenuItem("SelectAll");
     e_selectAll.addActionListener(this);

	  s_font=new JMenuItem("Font");
	  s_font.addActionListener(this);

	  s_color=new JMenuItem("Color");
	  s_color.addActionListener(this);

	  s_autoLine=new JCheckBoxMenuItem("AutoLine",true);
	  s_autoLine.addItemListener(this);

	  h_editor = new JMenuItem("About");
	  h_editor.addActionListener(this);

	  stateBar = new JLabel("NewFile");
	  stateBar.setHorizontalAlignment(SwingConstants.LEFT);
	  stateBar.setBorder(BorderFactory.createEtchedBorder());

	  //添加右键弹出式菜单
	  //popUpMenu = edit.getPopupMenu();

	  popUpMenu.add(je_copy);
	  popUpMenu.add(je_paste);
	  popUpMenu.add(je_cut);
	  popUpMenu.add(je_clear);
	

	 

	  // 编辑区键盘事件
	  textArea.addKeyListener(
	  new KeyAdapter()
	  {
	   public void keyTyped(KeyEvent e)
	   {
	    stateBar.setText("已修改");
	   }
	  });

	  // 编辑区鼠标事件,点击右键弹出"编辑"菜单
	  textArea.addMouseListener(
	  new MouseAdapter() {
	   public void mouseReleased(MouseEvent e) {
	    if(e.getButton() == MouseEvent.BUTTON3)
	    popUpMenu.show(e.getComponent(), e.getX(), e.getY());
	   }       

	   public void mouseClicked(MouseEvent e) {
	    if(e.getButton() == MouseEvent.BUTTON1)
	    popUpMenu.setVisible(false);
	   }
	  }
	  );

	  this.setJMenuBar(jmb);
	  this.setTitle("记事本");
	  Image image=this.getToolkit().getImage("zheng.gif");
	  this.setIconImage(image);

	  file.add(f_new);
	  file.add(f_open);
	  file.add(f_save);
	  file.add(f_saveas);
	  file.add(f_close);

	  edit.add(e_copy);
	  edit.add(e_paste);
	  edit.add(e_cut);
	  edit.add(e_clear);
	  edit.add(e_selectAll);

	  style.add(s_autoLine);
	  style.add(s_font);
	  style.add(s_color);

	  help.add(h_editor);                                                 

	  jmb.add(file);
	  jmb.add(edit);
	  jmb.add(style);
	  jmb.add(help);

	  b_save = new JButton("保存");
	  b_save.addActionListener(this);
	  b_close = new JButton("关闭");
	  b_close.addActionListener(this);


	  this.add(jsp);
	  this.setSize(800,600);
	  this.setVisible(true);

	  //设置窗口居中显示
	  int W = (int)Toolkit.getDefaultToolkit().getScreenSize().getWidth();
	  int H = (int)Toolkit.getDefaultToolkit().getScreenSize().getHeight();
	  this.setLocation((W-this.getWidth())/2,(H-this.getHeight())/2);

	  //为窗口添加"关闭"事件的响应
	  this.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
	  this.addWindowListener(new WindowAdapter()
	  {
	   public void windowClosing(WindowEvent e)
	   {
	    whenExit();
	   }
	  });
	 }      /////////////创建工作完成//////////////////
	 
	 //响应菜单项"自动换行"的事件
	 public void itemStateChanged(ItemEvent event)
	 {
	  if(event.getSource()==s_autoLine)
	  {
	   if(s_autoLine.getState())
	   {
	    textArea.setLineWrap(true);
	   }
	   else
	   textArea.setLineWrap(false);
	  }
	 }
	 
     //判断文件是否被修改
	 public  boolean isCurrentFileSaved()
	 {               
	  if(stateBar.getText().equals("已保存")||stateBar.getText().equals("新文档"))
	  {
	   return true;
	  }
	  else {
	   return false;
	  }
	 }
	 
	 //打开文件对话框
	 public void openFileDialog()
	 {
	  int m=jfc.showOpenDialog(this);
	  if(m== JFileChooser.APPROVE_OPTION)
	  {
	   File f=jfc.getSelectedFile();
	   for(int i=0;i<=f.length();i++)
	   {
	    char [] ch = new char[i];
	    try{
	     FileReader fr = new FileReader(f);
	     fr.read(ch);
	     String str = new String(ch);
	 
	     textArea.setText(str);
	 
	     isCurrentFileExists=true;
	     tempFile=f;
	    }
	    catch(FileNotFoundException fe )
	    {    JOptionPane.showMessageDialog(null,"未找到需要打开的文件!");   }
	    catch(IOException ie)
	    {   System.err.println(ie);     }
	   }
	  }
	  else
	   return;      
	 }
	 
	 //保存文件对话框
	 public void saveFileDialog()   
	 {
	  int options=jfc.showSaveDialog(this);
	  String fname = null;
	  if(options == JFileChooser.APPROVE_OPTION)
	  {
	   File f = jfc.getSelectedFile();//如果没有选取文件,下面的jfc.getName(f)将会返回输入的文件名
	   fname = jfc.getName(f);
	   if(fname != null && fname.trim().length()>0)
	   {
	    if(fname.endsWith(".txt"))
	    ;
	    else
	    {
	     fname = fname.concat(".txt");
	    }
	   }
	   if(f.isFile())
	   fname = f.getName();
	   f = jfc.getCurrentDirectory();
	   f = new File(f.getPath().concat(File.separator).concat(fname));

	   if(f.exists())
	   {
	    int i=JOptionPane.showConfirmDialog(null,"该文件已经存在，确定要覆盖吗？");
	    if(i ==JOptionPane.YES_OPTION)
	    ;
	    else
	    return;
	   }
	   try{
	    f.createNewFile();
	    String str=textArea.getText();
	    FileWriter fw = new FileWriter(f);
	    fw.write(str);
	    fw.close();

	    isCurrentFileExists=true;
	    tempFile=f;

	    stateBar.setText("已保存");
	   }
	   catch(Exception ex)
	   {
	    JOptionPane.showMessageDialog(null, "出错："+ ex.getMessage());
	    return ;
	   }
	  }
	 }
	 
	 //剪切
	 public void cut() {      
	  textArea.cut();
	  stateBar.setText("已修改");
	  popUpMenu.setVisible(false);
	 }

	 //复制
	 public void copy() {    
	  textArea.copy();
      popUpMenu.setVisible(false);
	 }
	 
     //粘贴
	 public void paste() {   
	  textArea.paste();
	  stateBar.setText("已修改");
	  popUpMenu.setVisible(false);
	 }
	 
	 //清除
	 public void clear(){    
	  textArea.replaceRange("",textArea.getSelectionStart(),textArea.getSelectionEnd());
	  stateBar.setText("已修改");
	  popUpMenu.setVisible(false);
	 }
	 
	 //全选
	 public void selectAll(){  
	  textArea.selectAll();
	 }

     //当退出程序时判断文档状态
	 public void whenExit()   
	 {
	  if(isCurrentFileSaved())   //关闭窗口时判断是否保存了文件
	  {
	   dispose();
	   System.exit(0);
	  }
	  else
	  {
	   int i=JOptionPane.showConfirmDialog(null,"文件未保存，是否要保存？","提示",JOptionPane.YES_NO_CANCEL_OPTION,JOptionPane.WARNING_MESSAGE);

	   if(i ==JOptionPane.YES_OPTION)
	   saveFileDialog();
	   else if(i==JOptionPane.NO_OPTION)
	   {
	    dispose();
	    System.exit(0);
	   }
	   else
	   return;
	  }
	 }
	 
	 
	 public void actionPerformed(ActionEvent e)