scrollpane problem

[naved momin]

i m making an editor, which has one panel , which inturn has labels which contains the line number and the editor is with frame
the problem is when i reachs end of the line surely editor goes up (similar when you type at the end and scrollpane allows you to view the text at the bottom of your editor)
my problem is line numbers label doesnt go in upward (though it is in scrollpane)
for eg
line number max goes to 35 then the screen finishes after that when i press enter editor scrolls down but this number panel doesnt scrolls down
i guess this will give you a better idea...what is going wrong

public class LineNumberOnEditor  {

    /**
     * @param args the command line arguments
     */
    
      
    private static JEditorPane editor;
    private JPanel panel;
    private JFrame frame;
    private int counter;
    private PrintWriter tempOut,htmlOut;
    private BufferedReader reader;
    private File tempFileLocation, htmlFileLocation;
    private JLabel numberLabel;
    private int lineNoInt = 0;
    private Integer lineNO = lineNoInt;
    private JPanel lineNumberPanel ;
    private JScrollPane scrollpane , lineNoScrollpane;
    private Font font ;
    
    public void startEditor()
    {
        frame = new JFrame("Editor");
        panel = new JPanel();
        editor = new JEditorPane();
        editor.setPreferredSize(new Dimension(1350,850));
       
        scrollpane = new JScrollPane(editor);
        
        
        numberLabel = new JLabel(lineNO.toString(),JLabel.RIGHT);
        
        settingCommonFont();
        settingLineNo();
        settingKeyAdapter();
        
        numberLabel.setFont(font);
        editor.setFont(font);
        editor.setBorder(BorderFactory.createEmptyBorder(10, 0, 0, 0));
      
       
        frame.add(scrollpane,BorderLayout.CENTER);
        frame.add(lineNoScrollpane,BorderLayout.WEST);
        frame.pack();
        frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
        
    }
     
    public static void main(String[] args) {
        // TODO code application logic here
        new LineNumberOnEditor().startEditor();
    }

    private void settingKeyAdapter() {
        class KeyListener extends KeyAdapter
        {
            @Override
            public void keyPressed(KeyEvent e)
            {
                if(e.getKeyCode() == KeyEvent.VK_ENTER)
                {
                    
                    incrementingLNumber();
                }
            }

            private void incrementingLNumber() {
                lineNoInt++;
                lineNO = lineNoInt;
                JLabel numberLabel = new JLabel(lineNO.toString());
                lineNumberPanel.add(numberLabel);
                lineNumberPanel.updateUI();
                numberLabel.setFont(font);
                
                
                System.out.println(lineNoInt);
            }
            
        }
        editor.addKeyListener(new KeyListener());
    }

    private void settingLineNo() {
        lineNumberPanel = new JPanel();
        lineNumberPanel.setBorder(BorderFactory.createEmptyBorder(10, 10, 0, 0));
        lineNumberPanel.setPreferredSize(new Dimension(60,5));
        BoxLayout box = new BoxLayout(lineNumberPanel, BoxLayout.Y_AXIS);
        lineNumberPanel.setLayout(box);
        lineNumberPanel.add(numberLabel);
        lineNoScrollpane = new JScrollPane(lineNumberPanel,ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS,ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
    }

    private void settingCommonFont() {
        font = new Font("Times New Roman",Font.BOLD,18);
    }
}

[Ranganathan Kaliyur Mannar]

You have set a very small preferred size for the lineNumber panel. Usually, when the size available for the component is larger than the preferred size, the scrollpane doesn't show the scrollbars. So, either change the height of the linenumberpanel or set the preferred size for the scrollpane itself instead of the panel.

[naved momin]

Ranganathan Kaliyur Mannar wrote:You have set a very small preferred size for the lineNumber panel. Usually, when the size available for the component is larger than the preferred size, the scrollpane doesn't show the scrollbars. So, either change the height of the linenumberpanel or set the preferred size for the scrollpane itself instead of the panel.

resolved