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import java.awt.*; import java.awt.event.*; import javax.swing.*; public class JNotePadUI extends JFrame { private JMenuItem menuOpen; private JMenuItem menuSave; private JMenuItem menuSaveAs; private JMenuItem menuClose; private JMenu editMenu; private JMenuItem menuCut; private JMenuItem menuCopy; private JMenuItem menuPaste; private JMenuItem menuAbout; private JTextArea textArea; private JLabel stateBar; private JFileChooser fileChooser; private JPopupMenu popUpMenu; public JNotePadUI() { super("新建文本文件"); setUpUIComponent(); setUpEventListener(); setVisible(true); } private void setUpUIComponent() { setSize(640, 480); // 菜单栏 JMenuBar menuBar = new JMenuBar(); // 设置「文件」菜单 JMenu fileMenu = new JMenu("文件"); menuOpen = new JMenuItem("打开"); // 快捷键设置 menuOpen.setAccelerator( KeyStroke.getKeyStroke( KeyEvent.VK_O, InputEvent.CTRL_MASK)); menuSave = new JMenuItem("保存"); menuSave.setAccelerator( KeyStroke.getKeyStroke( KeyEvent.VK_S, InputEvent.CTRL_MASK)); menuSaveAs = new JMenuItem("另存为"); menuClose = new JMenuItem("关闭"); menuClose.setAccelerator( KeyStroke.getKeyStroke( KeyEvent.VK_Q, InputEvent.CTRL_MASK)); fileMenu.add(menuOpen); fileMenu.addSeparator(); // 分隔线 fileMenu.add(menuSave); fileMenu.add(menuSaveAs); fileMenu.addSeparator(); // 分隔线 fileMenu.add(menuClose); // 设置「编辑」菜单 JMenu editMenu = new JMenu("编辑"); menuCut = new JMenuItem("剪切"); menuCut.setAccelerator( KeyStroke.getKeyStroke(KeyEvent.VK_X, InputEvent.CTRL_MASK)); menuCopy = new JMenuItem("复制"); menuCopy.setAccelerator( KeyStroke.getKeyStroke(KeyEvent.VK_C, InputEvent.CTRL_MASK)); menuPaste = new JMenuItem("粘贴"); menuPaste.setAccelerator( KeyStroke.getKeyStroke(KeyEvent.VK_V, InputEvent.CTRL_MASK)); editMenu.add(menuCut); editMenu.add(menuCopy); editMenu.add(menuPaste); // 设置「关于」菜单 JMenu aboutMenu = new JMenu("关于"); menuAbout = new JMenuItem("关于JNotePad"); aboutMenu.add(menuAbout); menuBar.add(fileMenu); menuBar.add(editMenu); menuBar.add(aboutMenu); setJMenuBar(menuBar); // 文字编辑区域 textArea = new JTextArea(); textArea.setFont(new Font("宋体", Font.PLAIN, 16)); textArea.setLineWrap(true); JScrollPane panel = new JScrollPane(textArea, ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED, ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER); Container contentPane = getContentPane(); contentPane.add(panel, BorderLayout.CENTER); // 状态栏 stateBar = new JLabel("未修改"); stateBar.setHorizontalAlignment(SwingConstants.LEFT); stateBar.setBorder( BorderFactory.createEtchedBorder()); contentPane.add(stateBar, BorderLayout.SOUTH); popUpMenu = editMenu.getPopupMenu(); fileChooser = new JFileChooser(); } private void setUpEventListener() { // 按下窗口关闭钮事件处理 addWindowListener( new WindowAdapter() { public void windowClosing(WindowEvent e) { closeFile(); } } ); // 菜单 - 打开 menuOpen.addActionListener( new ActionListener() { public void actionPerformed(ActionEvent e) { openFile(); } } ); // 菜单 - 保存 menuSave.addActionListener( new ActionListener() { public void actionPerformed(ActionEvent e) { saveFile(); } } ); // 菜单 - 另存为 menuSaveAs.addActionListener( new ActionListener() { public void actionPerformed(ActionEvent e) { saveFileAs(); } } ); // 菜单 - 关闭文件 menuClose.addActionListener( new ActionListener() { public void actionPerformed(ActionEvent e) { closeFile(); } } ); // 菜单 - 剪切 menuCut.addActionListener( new ActionListener() { public void actionPerformed(ActionEvent e) { cut(); } } ); // 菜单 - 复制 menuCopy.addActionListener( new ActionListener() { public void actionPerformed(ActionEvent e) { copy(); } } ); // 菜单 - 粘贴 menuPaste.addActionListener( new ActionListener() { public void actionPerformed(ActionEvent e) { paste(); } } ); // 菜单 - 关于 menuAbout.addActionListener( new ActionListener() { public void actionPerformed(ActionEvent e) { // 显示对话框 JOptionPane.showOptionDialog(null, "程序名称:\n JNotePad \n" + "程序设计:\n ???\n" + "简介:\n 一个简单的文字编辑器\n", "关于JNotePad", JOptionPane.DEFAULT_OPTION, JOptionPane.INFORMATION_MESSAGE, null, null, null); } } ); // 编辑区键盘事件 textArea.addKeyListener( new KeyAdapter() { public void keyTyped(KeyEvent e) { processTextArea(); } } ); // 编辑区鼠标事件 textArea.addMouseListener( new MouseAdapter() { public void mouseReleased(MouseEvent e) { if(e.getButton() == MouseEvent.BUTTON3) popUpMenu.show(editMenu, e.getX(), e.getY()); } public void mouseClicked(MouseEvent e) { if(e.getButton() == MouseEvent.BUTTON1) popUpMenu.setVisible(false); } } ); } private void openFile() { if(isCurrentFileSaved()) { // 文件是否为保存状态 open(); // 打开 } else { // 显示对话框 int option = JOptionPane.showConfirmDialog( null, "文件已修改，是否保存？", "保存文件？", JOptionPane.YES_NO_OPTION, JOptionPane.WARNING_MESSAGE, null); switch(option) { // 确认文件保存 case JOptionPane.YES_OPTION: saveFile(); // 保存文件 break; // 放弃文件保存 case JOptionPane.NO_OPTION: open(); break; } } } private boolean isCurrentFileSaved() { if(stateBar.getText().equals("未修改")) { return true; } else { return false; } } private void open() { // fileChooser 是 JFileChooser 的实例 // 显示文件选取的对话框 int option = fileChooser.showDialog(null, null); // 使用者按下确认键 if(option == JFileChooser.APPROVE_OPTION) { /* TODO: 添加读取文件的代码 */ } } private void saveFile() { /* TODO: 添加保存文件的代码 */ } private void saveFileAs() { /* TODO: 添加另存为的代码 */ } private void closeFile() { // 是否已保存文件 if(isCurrentFileSaved()) { // 释放窗口资源，而后关闭程序 dispose(); } else { int option = JOptionPane.showConfirmDialog( null, "文件已修改，是否保存？", "保存文件？", JOptionPane.YES_NO_OPTION, JOptionPane.WARNING_MESSAGE, null); switch(option) { case JOptionPane.YES_OPTION: saveFile(); break; case JOptionPane.NO_OPTION: dispose(); } } } private void cut() { textArea.cut(); stateBar.setText("已修改"); popUpMenu.setVisible(false); } private void copy() { textArea.copy(); popUpMenu.setVisible(false); } private void paste() { textArea.paste(); stateBar.setText("已修改"); popUpMenu.setVisible(false); } private void processTextArea() { stateBar.setText("已修改"); } public static void main(String[] args) { new JNotePadUI(); } } |
