简单文本编辑器

一、前言

二、界面预览

public class EditorDemo extends JFrame {
public static final String MAX_LINE_NUM = "9999";
private JTextPane textPane = new JTextPane(); //文本窗格，编辑窗口
private JLabel timeStatusBar = new JLabel(); //时间状态栏
private JLabel caretStatusBar = new JLabel(); //光标位置状态栏
private JFileChooser filechooser = new JFileChooser(); //文件选择器
private JPanel linePane = new JPanel(new FlowLayout(FlowLayout.CENTER, 0, 0));
private int lineNum = 0;
private  MyFont myFont = null;

private void initTextPaneDocument(){
textPane.getDocument().addDocumentListener(new DocumentListener() {
@Override
public void changedUpdate(DocumentEvent e) {}
@Override
public void insertUpdate(final DocumentEvent e) {
new Thread(new Runnable() {
@Override
public void run() {
DecorateKeyWords.decorateKeyWords(textPane, myFont);
}
}).start();
}
@Override
public void removeUpdate(DocumentEvent e) {
new Thread(new Runnable() {
@Override
public void run() {
String text;
try {
text = textPane.getDocument().getText(0, textPane.getDocument().getLength()).replaceAll("\\r", "");
Pattern pattern = Pattern.compile("\\n");
Matcher matcher = pattern.matcher(text);
int lineRow = 1;
while(matcher.find()){
//计算行数
++lineRow;
}
while(lineRow < linePane.getComponentCount()) {
--lineNum;
linePane.remove(linePane.getComponentCount()-1);
}
linePane.updateUI();

} catch (BadLocationException ex) {
ex.printStackTrace();
} finally {
DecorateKeyWords.decorateKeyWords(textPane, myFont);
}
}
}).start();
}
});
}

public EditorDemo() { //构造函数
super("简单的文本编辑器");  //调用父类构造函数

//初始字体
myFont = new MyFont();
myFont.setColor(Color.black);
myFont.setFont(new Font("宋体", Font.PLAIN, 24));
myFont.setSizeIndex(19);
myFont.setStyleIndex(0);
myFont.setColorIndex(0);

Action[] actions =  //Action数组,各种操作命令
{
new NewAction(),
new OpenAction(),
new SaveAction(),
new CutAction(),
new CopyAction(),
new PasteAction(),
new NewFontStyle(),
new AboutAction(),
new ExitAction()
};
textPane.addKeyListener(new KeyAdapter() {
@Override
public void keyPressed(KeyEvent e) {
super.keyPressed(e);
if(e.getKeyCode() == KeyEvent.VK_ENTER) {
//添加新的行号
addLineNum();
}
}
});

textPane.addCaretListener(new CaretListener() {
@Override
public void caretUpdate(CaretEvent e) {
try {
String text = textPane.getDocument().getText(0, e.getDot()).replaceAll("\\r", "");
Pattern pattern = Pattern.compile("\\n");
Matcher matcher = pattern.matcher(text);
int lineRow = 1;
int lastLineBeginPos = -1;//记录文本中最后一行的开始的位置
while(matcher.find()){
//计算行数
++lineRow;
lastLineBeginPos = matcher.start();//得到下一行光标所在的位置（根据上一行的换行符）
}
int lineCol = e.getDot() - lastLineBeginPos;
//显示行号和列号
caretStatusBar.setText("光标 " + lineRow + " : " + lineCol);
} catch (BadLocationException ey) {
ey.printStackTrace();
}
}
});
initTextPaneDocument();

setJMenuBar(createJMenuBar(actions));  //设置菜单栏
add(createJToolBar(actions), BorderLayout.NORTH); //增加工具栏
JPanel textBackPanel = new JPanel(new BorderLayout());
textBackPanel.add(linePane, BorderLayout.WEST);//增加行号面板
textBackPanel.add(textPane, BorderLayout.CENTER);//增加文本面板
add(new JScrollPane(textBackPanel), BorderLayout.CENTER); //文本窗格嵌入到JscrollPane
JPanel statusPane = new JPanel(new FlowLayout(FlowLayout.LEFT, 50, 0));
statusPane.add(caretStatusBar);
statusPane.add(timeStatusBar);
//初始化光标位置
caretStatusBar.setText("光标 1 : 1");
//初始化系统时间显示
new Timer().schedule(new TimerTask() {
@Override
public void run() {
Date now = new Date();
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//可以方便地修改日期格式
timeStatusBar.setText(dateFormat.format(now));
}
}, 0, 1000);
add(statusPane, BorderLayout.SOUTH); //增加状态栏

FontMetrics fm = FontDesignMetrics.getMetrics(myFont.getFont());
//设置光标的大小
textPane.setFont(myFont.getFont());
//设置行数面板的宽度
linePane.setPreferredSize(new Dimension(fm.stringWidth(MAX_LINE_NUM), 0));
addLineNum();

setBounds(200, 100, 800, 500); //设置窗口尺寸
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  //关闭窗口时退出程序
setVisible(true);  //设置窗口可视
}

private void addLineNum(){
//为textPane添加行号
String numText = String.valueOf(++lineNum);
int tmpNum = MAX_LINE_NUM.length() - (int)(Math.log10(lineNum*1.0)+1);
String spaces = "";
while(tmpNum > 0){
spaces += " ";
--tmpNum;
}
JLabel lineLabel = new JLabel(numText.replaceAll("(\\d+)", spaces+"$1"), JLabel.RIGHT);
lineLabel.setForeground(Color.GRAY);
lineLabel.setFont(myFont.getFont());
linePane.add(lineLabel);
linePane.updateUI();
}

private JMenuBar createJMenuBar(Action[] actions) {  //创建菜单栏
JMenuBar menubar = new JMenuBar(); //实例化菜单栏
JMenu menuFile = new JMenu("文件"); //实例化菜单
JMenu menuEdit = new JMenu("编辑");
JMenu menuAbout = new JMenu("帮助");
menuFile.add(new JMenuItem(actions[0])); //增加新菜单项
menuFile.add(new JMenuItem(actions[1]));
menuFile.add(new JMenuItem(actions[2]));
menuFile.add(new JMenuItem(actions[7]));
menuEdit.add(new JMenuItem(actions[3]));
menuEdit.add(new JMenuItem(actions[4]));
menuEdit.add(new JMenuItem(actions[5]));
menuAbout.add(new JMenuItem(actions[6]));
menubar.add(menuFile); //增加菜单
menubar.add(menuEdit);
menubar.add(menuAbout);
return menubar; //返回菜单栏
}

private JToolBar createJToolBar(Action[] actions) { //创建工具条
JToolBar toolBar = new JToolBar(); //实例化工具条
for (int i = 0; i < actions.length; i++) {
JButton bt = new JButton(actions[i]); //实例化新的按钮
bt.setRequestFocusEnabled(false); //设置不需要焦点
toolBar.add(bt); //增加按钮到工具栏
}
return toolBar;  //返回工具栏
}

class NewFontStyle extends AbstractAction{
public NewFontStyle() {
super("字体");
}
@Override
public void actionPerformed(ActionEvent e) {
JFontChooser one = new JFontChooser(myFont);
MyFont tmpFont = one.showDialog(null, "字体选择器", textPane.getLocationOnScreen().x, textPane.getLocationOnScreen().y);
if(tmpFont == null) return;
myFont = tmpFont;
//重新设置 textPane的字体，改变光标的大小
textPane.setFont(myFont.getFont());
FontMetrics fm = FontDesignMetrics.getMetrics(myFont.getFont());
//重新设置数字行数面板的宽度
linePane.setPreferredSize(new Dimension(fm.stringWidth(MAX_LINE_NUM), 0));
//重新设置行号的字体
for(int i=0; i < linePane.getComponentCount(); ++i)
linePane.getComponent(i).setFont(myFont.getFont());

StyledDocument doc = textPane.getStyledDocument();
SimpleAttributeSet wordAttr = new SimpleAttributeSet();
DecorateKeyWords.decorateStyleConstants(wordAttr, myFont.getFont());
doc.setCharacterAttributes(0, doc.getLength(), wordAttr, false);
}
}

class NewAction extends AbstractAction { //新建文件命令
public NewAction() {
super("新建");
}
public void actionPerformed(ActionEvent e) {
textPane.setDocument(new DefaultStyledDocument()); //清空文档
while(linePane.getComponentCount() > 1)
linePane.remove(linePane.getComponent(linePane.getComponentCount()-1));
linePane.updateUI();
lineNum = 1;
initTextPaneDocument();
}
}

class OpenAction extends AbstractAction { //打开文件命令
public OpenAction() {
super("打开");
}
public void actionPerformed(ActionEvent e) {
int i = filechooser.showOpenDialog(EditorDemo.this); //显示打开文件对话框
if (i == JFileChooser.APPROVE_OPTION) { //点击对话框中打开选项
File f = filechooser.getSelectedFile(); //得到选择的文件
try {
InputStream is = new FileInputStream(f); //得到文件输入流
textPane.read(is, "d"); //读入文件到文本窗格
is.close();
is = new FileInputStream(f);
LineNumberReader lnr = new LineNumberReader(new InputStreamReader(is));
lnr.skip(Long.MAX_VALUE);
int newLineNum = lnr.getLineNumber()+1;
lnr.close();
if(lineNum < newLineNum){
while(lineNum < newLineNum)
addLineNum();
} else {
while(lineNum > newLineNum && lineNum > 1){
linePane.remove(linePane.getComponentCount()-1);
--lineNum;
}
linePane.updateUI();
}

} catch (Exception ex) {
ex.printStackTrace();  //输出出错信息
}
}
DecorateKeyWords.decorateKeyWords(textPane, myFont);
initTextPaneDocument();
}
}

class SaveAction extends AbstractAction {  //保存命令
public SaveAction() {
super("保存");
}
public void actionPerformed(ActionEvent e) {
int i = filechooser.showSaveDialog(EditorDemo.this); //显示保存文件对话框
if (i == JFileChooser.APPROVE_OPTION) {  //点击对话框中保存按钮
File f = filechooser.getSelectedFile(); //得到选择的文件
try {
FileOutputStream out = new FileOutputStream(f);  //得到文件输出流
out.write(textPane.getText().getBytes()); //写出文件
} catch (Exception ex) {
ex.printStackTrace(); //输出出错信息
}
}
}
}

class ExitAction extends AbstractAction { //退出命令
public ExitAction() {
super("退出");
}
public void actionPerformed(ActionEvent e) {
System.exit(0);  //退出程序
}
}

class CutAction extends AbstractAction {  //剪切命令
public CutAction() {
super("剪切");
}
public void actionPerformed(ActionEvent e) {
textPane.cut();  //调用文本窗格的剪切命令
}
}

class CopyAction extends AbstractAction {  //拷贝命令
public CopyAction() {
super("拷贝");
}
public void actionPerformed(ActionEvent e) {
textPane.copy();  //调用文本窗格的拷贝命令
}
}

class PasteAction extends AbstractAction {  //粘贴命令
public PasteAction() {
super("粘贴");
}
public void actionPerformed(ActionEvent e) {
textPane.paste();  //调用文本窗格的粘贴命令
}
}

class AboutAction extends AbstractAction { //关于选项命令
public AboutAction() {
super("关于");
}
public void actionPerformed(ActionEvent e) {
JOptionPane.showMessageDialog(EditorDemo.this, "简单的文本编辑器演示"); //显示软件信息
}
}

public static void main(String[] args) {
new EditorDemo();
}
}