Java 使用复选框菜单项显示行号

我想使用复选框菜单项显示行号。我几乎完成了此任务。但是，这里的问题是，无论何时按enter键都只显示行号，而不是选中复选框菜单项。我想在单击复选框项本身时显示行号。请给我一些建议

以下是代码：

public class ViewLineNumbs extends javax.swing.JFrame {
int i=0;
JTextArea tx,lines;
JScrollPane scrollpane;
public ViewLineNumbs() {
    initComponents();
}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    tp = new javax.swing.JTabbedPane();
    jMenuBar1 = new javax.swing.JMenuBar();
    jMenu1 = new javax.swing.JMenu();
    Create = new javax.swing.JMenuItem();
    ViewLineNumbers = new javax.swing.JCheckBoxMenuItem();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    jMenu1.setText("File");

    Create.setText("Create");
    Create.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            CreateActionPerformed(evt);
        }
    });
    jMenu1.add(Create);

    ViewLineNumbers.setSelected(true);
    ViewLineNumbers.setText("ViewLineNumbers");
    ViewLineNumbers.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            ViewLineNumbersActionPerformed(evt);
        }
    });
    jMenu1.add(ViewLineNumbers);

    jMenuBar1.add(jMenu1);

    setJMenuBar(jMenuBar1);

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(tp, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 400, Short.MAX_VALUE)
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(tp, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 279, Short.MAX_VALUE)
    );

    pack();
}// </editor-fold>                        

private void CreateActionPerformed(java.awt.event.ActionEvent evt) {                                       
    final JInternalFrame internalFrame = new JInternalFrame("");
    i++;
    internalFrame.setName("Document"+i);
    internalFrame.setClosable(true);
    internalFrame.setAutoscrolls(true);
    tx=new JTextArea();
    tx.setFont(new java.awt.Font("Miriam Fixed", 0, 13));
    scrollpane=new JScrollPane(tx);
    internalFrame.add(scrollpane);
    tp.add(internalFrame);
    internalFrame.setSize(internalFrame.getMaximumSize());
    internalFrame.pack();
    internalFrame.setVisible(true);
}                                      

private void ViewLineNumbersActionPerformed(java.awt.event.ActionEvent evt) {                                                

        ViewLineNumbers.addItemListener(new ItemListener() {
               @Override
               public void itemStateChanged(ItemEvent ie) {
                  if(ViewLineNumbers.getState()){
                    lines = new JTextArea("");
                    lines.setBackground(Color.LIGHT_GRAY);
            lines.setEditable(false);
                    lines.setSize(10,10);
                    lines.setFont(new java.awt.Font("Miriam Fixed", 0, 13));
                    tx.getDocument().addDocumentListener(new DocumentListener(){
        public String getText(){
            int caretPosition = tx.getDocument().getLength();
            Element root = tx.getDocument().getDefaultRootElement();
            String text = "1" + System.getProperty("line.separator");
            for(int i = 2; i < root.getElementIndex( caretPosition ) + 1; i++){
                text += i + System.getProperty("line.separator");
            }
            return text;
         }
        @Override
        public void changedUpdate(DocumentEvent de) {
            lines.setText(getText());
        }
        @Override
        public void insertUpdate(DocumentEvent de) {
            lines.setText(getText());
        }

        @Override
        public void removeUpdate(DocumentEvent de) {
            lines.setText(getText());
        }
    });

                   scrollpane.getViewport().add(tx);
                   scrollpane.setRowHeaderView(lines); 
                   }
                   else{
                       scrollpane.setRowHeaderView(null);

                   }
               }
          });
}                                               

public static void main(String args[]) {
    /* Set the Nimbus look and feel */
    //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
    /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
     * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
     */
    try {
        for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                javax.swing.UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException ex) {
        java.util.logging.Logger.getLogger(ViewLineNumbs.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(ViewLineNumbs.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(ViewLineNumbs.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(ViewLineNumbs.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    //</editor-fold>

    /* Create and display the form */
    java.awt.EventQueue.invokeLater(new Runnable() {
        @Override
        public void run() {
            new ViewLineNumbs().setVisible(true);
        }
    });
}
// Variables declaration - do not modify                     
private javax.swing.JMenuItem Create;
private javax.swing.JCheckBoxMenuItem ViewLineNumbers;
private javax.swing.JMenu jMenu1;
private javax.swing.JMenuBar jMenuBar1;
private javax.swing.JTabbedPane tp;
// End of variables declaration                   

public类ViewLineNumbs扩展了javax.swing.JFrame{
int i=0；
JTEXT区域tx，线路；
JScrollPane滚动窗格；
公共ViewLineNumbs（）{
初始化组件（）；
}
@抑制警告（“未选中”）
//                           
私有组件（）{
tp=newjavax.swing.JTabbedPane（）；
jMenuBar1=newjavax.swing.JMenuBar（）；
jMenu1=newjavax.swing.JMenu（）；
Create=newjavax.swing.JMenuItem（）；
ViewLineNumbers=newjavax.swing.JCheckBoxMenuItem（）；
setDefaultCloseOperation（javax.swing.WindowConstants.EXIT_ON_CLOSE）；
setText（“文件”）；
Create.setText（“Create”）；
Create.addActionListener（新建java.awt.event.ActionListener（））{
public void actionPerformed（java.awt.event.ActionEvent evt）{
CreateActionPerformed（evt）；
}
});
jMenu1.add（Create）；
ViewLineNumber.setSelected（真）；
ViewLineNumbers.setText（“ViewLineNumbers”）；
ViewLineNumber.addActionListener（新java.awt.event.ActionListener（）{
public void actionPerformed（java.awt.event.ActionEvent evt）{
ViewLineNumberActionPerformed（evt）；
}
});
jMenu1.add（viewLineNumber）；
jMenuBar1.add（jMenu1）；
setJMenuBar（jMenuBar1）；
javax.swing.GroupLayout=newjavax.swing.GroupLayout（getContentPane（））；
getContentPane（）.setLayout（布局）；
layout.setHorizontalGroup(
createParallelGroup（javax.swing.GroupLayout.Alignment.LEADING）
.addComponent（tp，javax.swing.GroupLayout.Alignment.TRAILING，javax.swing.GroupLayout.DEFAULT\u SIZE，400，Short.MAX\u值）
);
layout.setVerticalGroup(
createParallelGroup（javax.swing.GroupLayout.Alignment.LEADING）
.addComponent（tp，javax.swing.GroupLayout.Alignment.TRAILING，javax.swing.GroupLayout.DEFAULT\u SIZE，279，Short.MAX\u值）
);
包装（）；
}//                         
私有void CreateActionPerformed（java.awt.event.ActionEvent evt）{
最终JInternalFrame internalFrame=新的JInternalFrame（“”）；
i++；
internalFrame.setName（“文件”+i）；
internalFrame.setClosable（真）；
internalFrame.setAutoscrolls（真）；
tx=新的JTextArea（）；
tx.setFont（新java.awt.Font（“Miriam Fixed”，0,13））；
滚动窗格=新的JScrollPane（tx）；
添加（滚动窗格）；
tp.add（内部框架）；
internalFrame.setSize（internalFrame.getMaximumSize（））；
internalFrame.pack（）；
internalFrame.setVisible（true）；
}                                      
private void ViewLineNumberActionPerformed（java.awt.event.ActionEvent evt）{
ViewLineNumber.addItemListener（新的ItemListener（）{
@凌驾
公共无效itemStateChanged（ItemEvent ie）{
if（viewLineNumber.getState（））{
行=新的JTextArea（“”）；
线条。背景（颜色。浅灰色）；
行。设置可编辑（false）；
行。设置大小（10,10）；
setFont（新java.awt.Font（“Miriam Fixed”，0,13））；
tx.getDocument（）.addDocumentListener（新DocumentListener（））{
公共字符串getText（）{
int caretPosition=tx.getDocument（）.getLength（）；
元素根=tx.getDocument（）.getDefaultRootElement（）；
String text=“1”+System.getProperty（“line.separator”）；
对于（int i=2；iprivate void CreateActionPerformed(java.awt.event.ActionEvent evt) {       
  AbstractButton btn = (AbstractButton) evt.getSource();
  if (btn.isSelected())                                
    // your stuff
  }
}

ViewLineNumbers.addItemListener(new ItemListener() {
      public void itemStateChanged(ItemEvent e) {
        System.out.println("Checked? " + check.isSelected());

//do your stuff here....
      }
    });

public class ViewLineNumbs extends javax.swing.JFrame {
int i=0;
JTextArea tx,lines;
JScrollPane scrollpane;
public ViewLineNumbs() {
    initComponents();
}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    tp = new javax.swing.JTabbedPane();
    jMenuBar1 = new javax.swing.JMenuBar();
    jMenu1 = new javax.swing.JMenu();
    Create = new javax.swing.JMenuItem();
    ViewLineNumbers = new javax.swing.JCheckBoxMenuItem();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    jMenu1.setText("File");

    Create.setText("Create");
    Create.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            CreateActionPerformed(evt);
        }
    });
    jMenu1.add(Create);

    ViewLineNumbers.setSelected(true);
    ViewLineNumbers.setText("ViewLineNumbers");
    ViewLineNumbers.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            ViewLineNumbersActionPerformed(evt);
        }
    });
    jMenu1.add(ViewLineNumbers);

    jMenuBar1.add(jMenu1);

    setJMenuBar(jMenuBar1);

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(tp, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 400, Short.MAX_VALUE)
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(tp, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 279, Short.MAX_VALUE)
    );

    pack();
}// </editor-fold>                        

private void CreateActionPerformed(java.awt.event.ActionEvent evt) {                                       
    final JInternalFrame internalFrame = new JInternalFrame("");
    i++;
    internalFrame.setName("Document"+i);
    internalFrame.setClosable(true);
    internalFrame.setAutoscrolls(true);
    tx=new JTextArea();
    tx.setFont(new java.awt.Font("Miriam Fixed", 0, 13));
    scrollpane=new JScrollPane(tx);
    internalFrame.add(scrollpane);
    tp.add(internalFrame);
    internalFrame.setSize(internalFrame.getMaximumSize());
    internalFrame.pack();
    internalFrame.setVisible(true);
}                                      

private void ViewLineNumbersActionPerformed(java.awt.event.ActionEvent evt) {                                                

        ViewLineNumbers.addItemListener(new ItemListener() {
               @Override
               public void itemStateChanged(ItemEvent ie) {
                  if(ViewLineNumbers.getState()){
                    lines = new JTextArea("");
                    lines.setBackground(Color.LIGHT_GRAY);
            lines.setEditable(false);
                    lines.setSize(10,10);
                    lines.setFont(new java.awt.Font("Miriam Fixed", 0, 13));
                    lines.setText(getText());
                    tx.getDocument().addDocumentListener(new DocumentListener(){

        @Override
        public void changedUpdate(DocumentEvent de) {
            lines.setText(getText());
        }
        @Override
        public void insertUpdate(DocumentEvent de) {
            lines.setText(getText());
        }

        @Override
        public void removeUpdate(DocumentEvent de) {
            lines.setText(getText());
        }
    });

                   scrollpane.getViewport().add(tx);
                   scrollpane.setRowHeaderView(lines); 
                   }
                   else{
                       scrollpane.setRowHeaderView(null);

                   }
               }
          });
}                                               
public String getText(){
    int caretPosition = tx.getDocument().getLength();
    Element root = tx.getDocument().getDefaultRootElement();
    String text = "1" + System.getProperty("line.separator");
    for(int i = 2; i < root.getElementIndex( caretPosition ) + 1; i++){
        text += i + System.getProperty("line.separator");
    }
    return text;
 }
public static void main(String args[]) {
    /* Set the Nimbus look and feel */
    //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
    /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
     * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
     */
    try {
        for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                javax.swing.UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException ex) {
        java.util.logging.Logger.getLogger(ViewLineNumbs.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(ViewLineNumbs.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(ViewLineNumbs.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(ViewLineNumbs.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    //</editor-fold>

    /* Create and display the form */
    java.awt.EventQueue.invokeLater(new Runnable() {
        @Override
        public void run() {
            new ViewLineNumbs().setVisible(true);
        }
    });
}
// Variables declaration - do not modify                     
private javax.swing.JMenuItem Create;
private javax.swing.JCheckBoxMenuItem ViewLineNumbers;
private javax.swing.JMenu jMenu1;
private javax.swing.JMenuBar jMenuBar1;
private javax.swing.JTabbedPane tp;
// End of variables declaration 
}

public class LineDocumentListener implements DocumentListener {

    private JTextComponent input;
    private JTextComponent output;

    public LineDocumentListener(JTextComponent comp, JTextComponent output) {
        this.input = comp;
        this.output = output;
        output.setText(getText());
    }

    public String getText() {
        int caretPosition = input.getDocument().getLength();
        Element root = input.getDocument().getDefaultRootElement();
        String text = "";
        int i = 1;
        for (; i < root.getElementIndex(caretPosition) + 1; i++) {
            text += i + System.getProperty("line.separator");
        }
        text += Integer.toString(i);
        return text;
    }

    @Override
    public void changedUpdate(DocumentEvent de) {
        output.setText(getText());
    }

    @Override
    public void insertUpdate(DocumentEvent de) {
        output.setText(getText());
    }

    @Override
    public void removeUpdate(DocumentEvent de) {
        output.setText(getText());
    }
}

int i = 1;
for (; i < root.getElementIndex(caretPosition) + 1; i++) {
    text += i + System.getProperty("line.separator");
}
text += Integer.toString(i);