import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.swing.undo.*;
import javax.swing.event.*;
public class NotePad extends JFrame {
 private UndoManager manager;
 private JFileChooser choose;
 private File selectedfile;
 private JTextArea text;
 private java.awt.Container container;
 private JMenuBar menuBar;
 private JTextField status;
 private boolean newPage = false;
 // File菜单
 private JMenu menu;
 private JMenuItem newText;
 private JMenuItem open;
 private JCheckBoxMenuItem readOnly;
 private JMenuItem save;
 private JMenuItem saveAs;
 private JMenuItem exit;
 // Edit菜单
 private JMenu edit;
 private JMenuItem undo;
 private JMenuItem redo;
 private JMenuItem cut;
 private JMenuItem copy;
 private JMenuItem copyAll;
 private JMenuItem paste;
 private JMenuItem delete;
 private JMenuItem deleteAll;
 private JMenuItem selectAll;
 private JMenuItem searchAndReplace;
 // 视图菜单
 private JMenu view;
 private JCheckBoxMenuItem wrap;
 private JCheckBoxMenuItem onTop;
 private JMenuItem zoomIn;
 private JMenuItem zoomOut;
 // 工具菜单
 private JMenu tool;
 private JMenuItem fontSum;
 private JMenuItem setcolor;
 private JMenuItem setFontColor;
 // 帮助菜单
 private JMenu help;
 private JMenuItem about;
 // 右键菜单
 private JPopupMenu pop;
 private JMenuItem popUndo;
 private JMenuItem popRedo;
 private JMenuItem popCut;
 private JMenuItem popCopy;
 private JMenuItem popSelectAll;
 private JMenuItem popCopyAll;
 private JMenuItem popPaste;
 private JMenuItem popDelete;
 private JMenuItem popClear;

 public NotePad() {
  super("记事本");
  try{
   UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
  }catch(Exception e){}
  container = getContentPane();
  container.setLayout(new BorderLayout(0,-2));
  manager = new UndoManager();
  text = new JTextArea();
  text.setFont(new Font("宋体",Font.PLAIN,14));
  text.getDocument().addUndoableEditListener(manager);
  text.setTabSize(2);
  text.setSelectedTextColor(Color.WHITE);
  text.setSelectionColor(Color.DARK_GRAY);
  text.setLineWrap(true);
  text.setWrapStyleWord(true);
  text.setCaretColor(Color.RED);
  text.setMargin(new Insets(3, 10, 3, 7));
  text.setDragEnabled(true);
  container.add(new JScrollPane(text,JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED));
  menuBar = new JMenuBar();
  // File菜单
  menu = new JMenu("文件(F)");
  menu.setMnemonic('F');
  newText = new JMenuItem("新建(N)");
  newText.setMnemonic('N');
  newText.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent event) {
    if(selectedfile == null && !text.getText().equals("")  &&
      JOptionPane.showConfirmDialog(container, "是否保存", "是否保存", JOptionPane.YES_NO_OPTION) == JOptionPane.YES_OPTION){
     choose = new JFileChooser();
     int state = choose.showSaveDialog(container);
     if (state == JFileChooser.APPROVE_OPTION) {
      try {
       File file = choose.getSelectedFile();
       FileWriter os = new FileWriter(file);
       os.write(text.getText(), 0, text.getText().length());
       os.flush();
       file.createNewFile();
       os.close();
      } catch (IOException e) {
       JOptionPane.showMessageDialog(container, "保存文件失败","ERROR", JOptionPane.ERROR_MESSAGE);
      }
     }
    }else if(selectedfile != null && 
      JOptionPane.showConfirmDialog(container, "是否保存", "是否保存", JOptionPane.YES_NO_OPTION) == JOptionPane.YES_OPTION){
    try {
      FileWriter os = new FileWriter(selectedfile);
      os.write(text.getText(), 0, text.getText().length());
      os.flush();
      os.close();
    } catch (IOException e) {}
   }
   text.setText("");
   newPage = true; 
   selectedfile = null;
   status.setText("");
   }
  });

  open = new JMenuItem("打开(O)");
  open.setMnemonic('O');
  open.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent event) {
    if(selectedfile!=null && 
      JOptionPane.showConfirmDialog(container, "是否保存", "是否保存", JOptionPane.YES_NO_OPTION) == JOptionPane.YES_NO_OPTION){
     try{
      FileWriter os = new FileWriter(selectedfile);
      os.write(text.getText(), 0, text.getText().length());
      os.flush();
      os.close();
      newPage = false;
     }catch(IOException e){}
    }else if(selectedfile==null && !text.getText().equals("") &&
      JOptionPane.showConfirmDialog(container, "是否保存", "是否保存", JOptionPane.YES_NO_OPTION) == JOptionPane.YES_NO_OPTION){
     choose = new JFileChooser();
     int state = choose.showSaveDialog(container);
     if (state == JFileChooser.APPROVE_OPTION) {
      try {
       File file = choose.getSelectedFile();
       FileWriter os = new FileWriter(file);
       os.write(text.getText(), 0, text.getText().length());
       os.flush();
       file.createNewFile();
       os.close();
       newPage = false;
      } catch (IOException e) {
       JOptionPane.showMessageDialog(container, "保存文件失败",
         "ERROR", JOptionPane.ERROR_MESSAGE);
      }
     }
    }
    choose = new JFileChooser();
    choose.setFileFilter(new filter());
    int state = choose.showOpenDialog(container);
    if (state == JFileChooser.APPROVE_OPTION) {
     status.setText(choose.getSelectedFile().toString());
     try {
      selectedfile = choose.getSelectedFile();
      FileReader isr = new FileReader(selectedfile);
      text.read(isr, "");
      isr.close();
      newPage = false;
     } catch (IOException e) {
      JOptionPane.showMessageDialog(container, "打开文件失败",
        "ERROR", JOptionPane.ERROR_MESSAGE);
     }
    }

   }
  });

  readOnly = new JCheckBoxMenuItem("只读模式(R)");
  readOnly.setMnemonic('R');
  readOnly.addChangeListener(new ChangeListener() {
   public void stateChanged(ChangeEvent event) {
    if(readOnly.isSelected()){
     text.setEditable(false);
     cut.setEnabled(false);
     paste.setEnabled(false);
     delete.setEnabled(false);
     deleteAll.setEnabled(false);
     redo.setEnabled(false);
     undo.setEnabled(false);
     searchAndReplace.setEnabled(false);
     
     popClear.setEnabled(false);
     popCut.setEnabled(false);
     popDelete.setEnabled(false);
     popPaste.setEnabled(false);
     popRedo.setEnabled(false);
     popUndo.setEnabled(false);
    }
    else{
     text.setEditable(true);
     cut.setEnabled(true);
     paste.setEnabled(true);
     delete.setEnabled(true);
     deleteAll.setEnabled(true);
     redo.setEnabled(true);
     undo.setEnabled(true);
     searchAndReplace.setEnabled(true);
     
     popClear.setEnabled(true);
     popCut.setEnabled(true);
     popDelete.setEnabled(true);
     popPaste.setEnabled(true);
     popRedo.setEnabled(true);
     popUndo.setEnabled(true);
    }
   }
  });

  save = new JMenuItem("保存(S)");
  save.setMnemonic('S');
  save.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent event) {
    if (newPage == true || selectedfile == null) {
     choose = new JFileChooser();
     int state = choose.showSaveDialog(container);
     if (state == JFileChooser.APPROVE_OPTION) {
      try {
       File file = choose.getSelectedFile();
       FileWriter os = new FileWriter(file);
       os.write(text.getText(), 0, text.getText().length());
       os.flush();
       file.createNewFile();
       os.close();
       newPage = false;
      } catch (IOException e) {
       JOptionPane.showMessageDialog(container, "保存文件失败","ERROR", JOptionPane.ERROR_MESSAGE);
      }
     }
    } else if(newPage == false && selectedfile != null){
     try {
      FileWriter os = new FileWriter(selectedfile);
      os.write(text.getText(), 0, text.getText().length());
      os.flush();
      os.close();
     } catch (IOException e) {
      JOptionPane.showMessageDialog(container, "保存文件失败","ERROR", JOptionPane.ERROR_MESSAGE);
     }
    }
   }
  });

  saveAs = new JMenuItem("另存为(A)");
  saveAs.setMnemonic('A');
  saveAs.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent event) {
    choose = new JFileChooser();
    int state = choose.showSaveDialog(container);
    if (state == JFileChooser.APPROVE_OPTION) {
     try {
      File file = choose.getSelectedFile();
      FileWriter os = new FileWriter(file);
      os.write(text.getText(), 0, text.getText().length());
      os.flush();
      file.createNewFile();
      os.close();
      newPage = false;
     } catch (IOException e) {
      JOptionPane.showMessageDialog(container, "保存文件失败","ERROR", JOptionPane.ERROR_MESSAGE);
     }
    }
   }
  });

  exit = new JMenuItem("退出(Q)");
  exit.setMnemonic('Q');
  exit.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent event) {
    System.exit(0);
   }
  });

  menu.add(newText);
  menu.add(open);
  menu.add(readOnly);
  menu.add(save);
  menu.add(saveAs);
  menu.add(exit);