texteditframe.java

java灵感设计

package textedit;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import javax.swing.text.*;
/**
 * <p>Title: TextEditDemo</p>
 * <p>Description: This is a TextEdit demo</p>
 * <p>Copyright: Copyright (c) 2002</p>
 * <p>Company: d6-125</p>
 * @author Liujun
 * @version 1.0
 */

public class TextEditFrame extends JFrame {
  JPanel contentPane;
  JMenuBar jMenuBar1 = new JMenuBar();
  JMenu jMenuFile = new JMenu();
  JMenuItem jMenuFileExit = new JMenuItem();
  JMenu jMenuHelp = new JMenu();
  JMenuItem jMenuHelpAbout = new JMenuItem();
  JLabel statusBar = new JLabel();
  BorderLayout borderLayout1 = new BorderLayout();
  JMenuItem jMenuItem1 = new JMenuItem();
  JMenuItem jMenuItem2 = new JMenuItem();
  JMenuItem jMenuItem3 = new JMenuItem();
  JMenuItem jMenuItem4 = new JMenuItem();
  JFileChooser jFileChooser1 = new JFileChooser();
  JScrollPane jScrollPane1 = new JScrollPane();
  JTextArea jTextArea1 = new JTextArea();

  String currFileName = null;  // 需要完整路径的文件名，null 表示新文件或无文件名。
  boolean dirty = false;//表示文本是否被修改过。

  //Construct the frame
  public TextEditFrame() {
    enableEvents(AWTEvent.WINDOW_EVENT_MASK);
    try {
      jbInit();
    }
    catch(Exception e) {
      e.printStackTrace();
    }
  }
  //Component initialization
  private void jbInit() throws Exception  {
    //setIconImage(Toolkit.getDefaultToolkit().createImage(TextEditFrame.class.getResource("[Your Icon]")));
    contentPane = (JPanel) this.getContentPane();
    contentPane.setLayout(borderLayout1);
    this.setSize(new Dimension(400, 300));
    this.setTitle("Text Edit Frame Demo");
    statusBar.setText(" ");
    jMenuFile.setText("File");
    jMenuFileExit.setText("Exit");
    jMenuFileExit.addActionListener(new ActionListener()  {
      public void actionPerformed(ActionEvent e) {
        jMenuFileExit_actionPerformed(e);
      }
    });
    jMenuHelp.setText("Help");
    jMenuHelpAbout.setIcon(new ImageIcon(new java.net.URL("file:///L:/jb6exam/TextEdit/TextEdit/src/image/help.gif")));
    jMenuHelpAbout.setText("About");
    jMenuHelpAbout.addActionListener(new ActionListener()  {
      public void actionPerformed(ActionEvent e) {
        jMenuHelpAbout_actionPerformed(e);
      }
    });
    jMenuItem1.setIcon(new ImageIcon(new java.net.URL("file:///L:/jb6exam/TextEdit/TextEdit/src/image/NewFile.GIF")));
    jMenuItem1.setText("New");
    jMenuItem1.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
        jMenuItem1_actionPerformed(e);
      }
    });
    jMenuItem2.setIcon(new ImageIcon(new java.net.URL("file:///L:/jb6exam/TextEdit/TextEdit/src/image/openFile.gif")));
    jMenuItem2.setText("Open");
    jMenuItem2.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
        jMenuItem2_actionPerformed(e);
      }
    });
    jMenuItem3.setIcon(new ImageIcon(new java.net.URL("file:///L:/jb6exam/TextEdit/TextEdit/src/image/closeFile.gif")));
    jMenuItem3.setText("Save");
    jMenuItem3.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
        jMenuItem3_actionPerformed(e);
      }
    });
    jMenuItem4.setIcon(new ImageIcon(new java.net.URL("file:///L:/jb6exam/TextEdit/TextEdit/src/image/closeFile.gif")));
    jMenuItem4.setText("Save As");
    jMenuItem4.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
        jMenuItem4_actionPerformed(e);
      }
    });
    jMenuFile.add(jMenuItem1);
    jMenuFile.add(jMenuItem2);
    jMenuFile.add(jMenuItem3);
    jMenuFile.add(jMenuItem4);
    jMenuFile.addSeparator();
    jMenuFile.add(jMenuFileExit);
    jMenuHelp.add(jMenuHelpAbout);
    jMenuBar1.add(jMenuFile);
    jMenuBar1.add(jMenuHelp);
    this.setJMenuBar(jMenuBar1);
    contentPane.add(statusBar, BorderLayout.SOUTH);
    contentPane.add(jScrollPane1, BorderLayout.CENTER);
    jScrollPane1.getViewport().add(jTextArea1, null);
  }
  //File | Exit action performed
  public void jMenuFileExit_actionPerformed(ActionEvent e) {
    System.exit(0);
  }
  //Help | About action performed
  public void jMenuHelpAbout_actionPerformed(ActionEvent e) {
    TextEditFrame_AboutBox dlg = new TextEditFrame_AboutBox(this);
    Dimension dlgSize = dlg.getPreferredSize();
    Dimension frmSize = getSize();
    Point loc = getLocation();
    dlg.setLocation((frmSize.width - dlgSize.width) / 2 + loc.x, (frmSize.height - dlgSize.height) / 2 + loc.y);
    dlg.setModal(true);
    dlg.show();
  }

  void openFile(String fileName)  {
  //打开文件，从文件中读取文本到文本框同时向状态栏报告状态信息.
    try
    {
      File file = new File(fileName);
      int size = (int)file.length();
      int chars_read = 0;//设置文件读指针
      FileReader in = new FileReader(file);
      char[] data = new char[size];
      while(in.ready()) {//读文件数据
        chars_read += in.read(data, chars_read, size - chars_read);
      }
      in.close();//关闭文件
      jTextArea1.setText(new String(data, 0, chars_read));
      this.currFileName = fileName;
      this.dirty = false;
      statusBar.setText("打开了文件：" + fileName);
      updateCaption();
    }
    catch (IOException e)
    {
      statusBar.setText("文件打开错误： " + fileName);
    }
  }

  void fileOpen() {
    if (!okToAbandon()) {//如果上一个文件被修改过了，则询问用户。
      return;
    }
    if (JFileChooser.APPROVE_OPTION == jFileChooser1.showOpenDialog(this)) {
      openFile(jFileChooser1.getSelectedFile().getPath());//打开文件
    }
    this.repaint();
  }

  boolean saveFile() {
  //保存文件
    if (currFileName == null) {//如果文件名为空，提示给出文件名
      return saveAsFile();
    }

    try
    {
      File file = new File (currFileName);
      FileWriter out = new FileWriter(file);
      String text = jTextArea1.getText();
      out.write(text);//写文件
      out.close();//关闭文件
      this.dirty = false;//文件已保存
      statusBar.setText("Saved to " + currFileName);
      updateCaption();//修改标题栏
      return true;
    }
    catch (IOException e) {
      statusBar.setText("Error saving " + currFileName);
    }
    return false;
  }

  boolean saveAsFile() {
    this.repaint();
    if (JFileChooser.APPROVE_OPTION == jFileChooser1.showSaveDialog(this)) {
      currFileName = jFileChooser1.getSelectedFile().getPath();
      this.repaint();
      return saveFile();
    }
    else {
      this.repaint();
      return false;
    }
  }

  boolean okToAbandon() {
  // 检查文件是否被修改过，显示"保存? yes/no/cancel"信息，让用户决定是否保存。
    if (!dirty) {
      return true;
    }
    int value =  JOptionPane.showConfirmDialog(this, "保存修改？",
                                         "Text Edit", JOptionPane.YES_NO_CANCEL_OPTION) ;

    switch (value) {
       case JOptionPane.YES_OPTION:
         // 保存修改后的文件
         return saveFile();
       case JOptionPane.NO_OPTION:
         // 取消保存修改过的文件
         return true;
       case JOptionPane.CANCEL_OPTION:
       default:
         // 取消操作
         return false;
    }
  }

  void updateCaption() {
    //更新标题显示文件名和更改信息标志。
    String caption;
    if (currFileName == null) {
       // 无文件名则使用"Untitled"。
       caption = "Untitled";
    }
    else {
      caption = currFileName;
    }

    // 添加更改信息标志 "*"。
    if (dirty) {
      caption = "* " + caption;
    }
    caption = "Text Editor - " + caption;
    this.setTitle(caption);
  }

  //Overridden so we can exit when window is closed
  protected void processWindowEvent(WindowEvent e) {
    super.processWindowEvent(e);
    if (e.getID() == WindowEvent.WINDOW_CLOSING) {
      jMenuFileExit_actionPerformed(null);
    }
  }

  void jMenuItem1_actionPerformed(ActionEvent e) {
    // Handle the File|New menu item.
    if (okToAbandon()) {
      // 清空TextArea组件内容
      jTextArea1.setText("");
      // 清空文件名和更改信息标志
      currFileName = null;
      dirty = false;
      updateCaption();
    }
  }

  void jMenuItem2_actionPerformed(ActionEvent e) {
    //Handle the File|Open menu item.
    fileOpen();
  }

  void jMenuItem3_actionPerformed(ActionEvent e) {
    //Handle the File|Save menu item.
    saveFile();
  }

  void jMenuItem4_actionPerformed(ActionEvent e) {
    //Handle the File|Save As menu item.
    saveAsFile();
  }
}