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Line numbers for text area

Posted on 2003-12-08
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Last Modified: 2010-08-05
How do i get the line numbers on the left side of text area which has a scroll bar. I am designing an IDE. I am using Java 2.1.2.
I have to use Java 2 1.2 only >please "don't" suggest java 1.4 solutions
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Question by:neekris
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5 Comments
 
LVL 35

Expert Comment

by:TimYates
ID: 9897305
This should do it:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
import javax.swing.border.*;


public class Test2 extends JFrame {

      JTextArea jta = new JTextArea(),
                      line = new JTextArea();
      int lineNumber = 1;
      
      public Test2() {
                 
        JScrollPane scroller = new JScrollPane( jta,
                         ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS,
                         ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS );
      
        scroller.setRowHeaderView( line );
        line.append( 1 + " 
" );
        
        Border border = BorderFactory.createEtchedBorder();
        JPanel jpb = new JPanel();
        jpb.setBorder( border );
        
        jta.addCaretListener( new CaretListener() {
            public void caretUpdate(CaretEvent e) {
                          try {
                  int n = jta.getLineOfOffset( jta.getCaretPosition() ) + 1;
                     if ( n > lineNumber ) {
                       line.append( (lineNumber+1) + " 
" );
                               lineNumber++;
                             }
                      } catch (BadLocationException ble) {
                            System.out.println(" line exception! ");
                      }
                  }
     });
        
        scroller.setCorner( ScrollPaneConstants.LOWER_LEFT_CORNER, jpb );
      
        Container contentPane = getContentPane();
        addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent e)
{                                                                                                                                                                                                                                    
                          System.exit(0);
         }
     });
       
        contentPane.add(scroller, BorderLayout.CENTER);            
            
      }
          
      public static void main( String args[] ) {
            
            Test2 test = new Test2();
            test.setBounds( 50, 50, 400, 400 );
            test.setVisible(true);
            
      }
      
}
0
 
LVL 35

Accepted Solution

by:
TimYates earned 250 total points
ID: 9897309
SORRRY!!!!!!!!!!!


This:

----------------------

import java.awt.* ;
import java.awt.event.* ;
import javax.swing.* ;
import javax.swing.event.* ;
import javax.swing.text.* ;
import javax.swing.border.* ;

public class Test2
    extends JFrame
{

  JTextArea jta = new JTextArea(),
                  line = new JTextArea() ;
  int lineNumber = 1 ;

  public Test2()
  {

    JScrollPane scroller = new JScrollPane( jta,
                                            ScrollPaneConstants.
                                            VERTICAL_SCROLLBAR_ALWAYS,
                                            ScrollPaneConstants.
                                            HORIZONTAL_SCROLLBAR_ALWAYS ) ;

    scroller.setRowHeaderView( line ) ;
    line.append( 1 + "\n" ) ;

    Border border = BorderFactory.createEtchedBorder() ;
    JPanel jpb = new JPanel() ;
    jpb.setBorder( border ) ;

    jta.addCaretListener( new CaretListener()
    {
      public void caretUpdate( CaretEvent e )
      {
        try
        {
          int n = jta.getLineOfOffset( jta.getCaretPosition() ) + 1 ;
          if( n > lineNumber )
          {
            line.append( ( lineNumber + 1 ) + "\n" ) ;
            lineNumber++ ;
          }
        }
        catch( BadLocationException ble )
        {
          System.out.println( " line exception! " ) ;
        }
      }
    } ) ;

    scroller.setCorner( ScrollPaneConstants.LOWER_LEFT_CORNER, jpb ) ;

    Container contentPane = getContentPane() ;
    addWindowListener( new WindowAdapter()
    {
      public void windowClosing( WindowEvent e )
      {
        System.exit( 0 ) ;
      }
    } ) ;

    contentPane.add( scroller, BorderLayout.CENTER ) ;

  }

  public static void main( String args[] )
  {

    Test2 test = new Test2() ;
    test.setBounds( 50, 50, 400, 400 ) ;
    test.setVisible( true ) ;

  }

}
0
 
LVL 35

Expert Comment

by:TimYates
ID: 9897314
0
 

Author Comment

by:neekris
ID: 9902272
Good,But when i save the text area how do i get rid of the line numbers
0
 
LVL 35

Expert Comment

by:TimYates
ID: 9902720
Just save jta...

the line numbers are in a seperate textarea, which is on the left of the jta text area (the main one)

Tim.
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