自制简单的记事本
程序代码：package com.tocean.ch15.exec;
import java.awt.BorderLayout;
public class NotePad extends JFrame implements ActionListener {
private JPanel contentPane;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
NotePad frame = new NotePad();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* 通过拖拉方式弄成的界面
*/
public NotePad() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 684, 444);
JMenuBar menuBar = new JMenuBar();
setJMenuBar(menuBar);
JMenu menu = new JMenu("\u6587\u4EF6");
menuBar.add(menu);
newMenuItem = new JMenuItem("\u65B0\u5EFA");
newMenuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_N,
InputEvent.CTRL_MASK));
menu.add(newMenuItem);
openMenuItem = new JMenuItem("\u6253\u5F00");
openMenuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_O,
InputEvent.CTRL_MASK));
menu.add(openMenuItem);
saveMenuItem = new JMenuItem("\u4FDD\u5B58");
saveMenuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S,
InputEvent.CTRL_MASK));
menu.add(saveMenuItem);
saveasMenuItem = new JMenuItem("\u53E6\u5B58\u4E3A");
menu.add(saveasMenuItem);
exitMenuItem = new JMenuItem("\u9000\u51FA");
menu.add(exitMenuItem);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
contentPane.setLayout(new BorderLayout(0, 0));
setContentPane(contentPane);
textPane = new JTextPane();
contentPane.add(textPane, BorderLayout.CENTER);
addListeners();
}
/**
* 注册事件
*/
private void addListeners() {
exitMenuItem.addActionListener(this);
saveasMenuItem.addActionListener(this);
saveMenuItem.addActionListener(this);
newMenuItem.addActionListener(this);
openMenuItem.addActionListener(this);
textPane.addKeyListener(new KeyAdapter(){
@Override
public void keyTyped(KeyEvent e) {
isSaved=false;
super.keyTyped(e);
}
});
}
/**
* 打开
*/
private void open(){
if ( !isSaved) {// 表示该文件是一个新建的文件
int ok = JOptionPane.showConfirmDialog(this, "是否保存正在编辑的文件？");
if (JOptionPane.YES_OPTION == ok) {
if (saveFile == null) {
saveAs();
} else {
save();
}
}
}
JFileChooser jfc = new JFileChooser();
int option=jfc.showOpenDialog(this);
if(JFileChooser.APPROVE_OPTION==option){
saveFile =jfc.getSelectedFile();
isSaved=true;
this.setTitle(saveFile.getAbsolutePath());
//用流读取文件内容，然后显示到JTextPanes上
BufferedReader in = null;
try {
in = new BufferedReader(new FileReader(saveFile));
String line=null;
StringBuffer sb=new StringBuffer();
while((line=in.readLine())!=null){
sb.append(line).append("\n");
}
textPane.setText(sb.toString());
} catch (IOException e) {
e.printStackTrace();
} finally {
if (null != in)
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
/**
* 新建文件
* 保存正在编辑的文件
*/
private void newFile() {
if ( !isSaved) {// 表示该文件是一个新建的文件
int ok = JOptionPane.showConfirmDialog(this, "是否保存正在编辑的文件？");
if (JOptionPane.YES_OPTION == ok) {
if (saveFile == null) {
saveAs();
} else {
save();
}
}
}
textPane.setText("");
saveFile = null;
isSaved=false;
this.setTitle("新建文件");
}
/**
* 保存
*/
private void save() {
if (null == saveFile) {// 表示该文件是一个新建的文件
saveAs();
} else {// 如果不为空，表明已经当前正在编辑的文件就是saveFile
String content = textPane.getText();
saveFile(saveFile, content);
isSaved = true;
}
}
/**
* 另存为
*/
private void saveAs() {
JFileChooser jfc = new JFileChooser();
int option = jfc.showSaveDialog(this);
if (JFileChooser.APPROVE_OPTION == option) {
File file = jfc.getSelectedFile();
String content = textPane.getText();
if (file.exists()) {// 如果原有文件已经存在，则提示覆盖
int ok = JOptionPane.showConfirmDialog(this, "该文件已经存在，是否覆盖文件?");
if (JOptionPane.YES_OPTION == ok) {
saveFile(file, content);
isSaved = true;
saveFile = file;
this.setTitle(file.getAbsolutePath());
}
} else {// 如果文件不存在，则直接保存
saveFile(file, content);
isSaved = true;
saveFile = file;
this.setTitle(file.getAbsolutePath());
}
}
}
/**
* 保存文件
*/
private void saveFile(File file, String content) {
BufferedWriter out = null;
try {
out = new BufferedWriter(new FileWriter(file));
out.write(content);
out.flush();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (null != out)
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* 退出
*/
private void exit() {
if (!isSaved) {
int ok = JOptionPane.showConfirmDialog(this, "是否保存文件");
if (JOptionPane.YES_OPTION == ok) {
saveAs();
System.exit(0);
} else if (JOptionPane.NO_OPTION == ok) {
System.exit(0);
}
}
System.exit(0);
}
@Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == exitMenuItem) {
exit();
} else if (e.getSource() == saveasMenuItem) {
saveAs();
} else if (e.getSource() == saveMenuItem) {
save();
} else if (e.getSource() == newMenuItem) {
newFile();
}else if (e.getSource() == openMenuItem) {
open();
}
}
private JTextPane textPane;
private File saveFile;
private boolean isSaved = false;
private JMenuItem exitMenuItem;
private JMenuItem saveasMenuItem;
private JMenuItem saveMenuItem;
private JMenuItem newMenuItem;
private JMenuItem openMenuItem;
}
