Highlighting line in JTextArea

[misiom1]

Hello

I would like to highlight the line on which mouse clicked, something like in notepad++ and other code editors. I'm not quite sure how to do it. I'm new to Java and googled lots of pages but haven't found anything written in language for begginiers, could anybody direct me how to do it?

Thank you

[Fubarable]

You can get the clicked line via the viewToModel(Point p), getLineOfOffset(int offset), getLineStartOffset(int line), and getLineEndOffset(int line) methods. I'll have to review highlighting as it's been a while since I've done this. Of course you would need a MouseListener too. I suggest you construct an SSCCE that we can work with if you still need help. Please check out the link to tell you how to do this.

[JosAH]

I would like to highlight the line on which mouse clicked, something like in notepad++ and other code editors. I'm not quite sure how to do it. I'm new to Java and googled lots of pages but haven't found anything written in language for begginiers, could anybody direct me how to do it?

Camickr (the Swing wizard) has put a bunch of great tools/classes online. One of them is this one; it does exactly what you want. Credits go to Camickr (and his site worth bookmarking).

kind regards,

Jos

[Fubarable]

Edit: I was wrong. You wouldn't use the getLineOfOffset(int offset), getLineStartOffset(int line), and getLineEndOffset(int line) methods but rather the viewToModel(Point p) and modelToView(int offset) methods. For example:

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

@SuppressWarnings("serial")
public class HighlightTextAreaLine extends JPanel {
   private JTextArea tArea = new JTextArea(20, 40);

   public HighlightTextAreaLine() {
      tArea.setWrapStyleWord(true);
      tArea.setLineWrap(true);

      for (int i = 0; i < 400; i++) {
         tArea.append("abcdefg ");
      }

      add(new JScrollPane(tArea));

      tArea.addMouseListener(new MouseAdapter() {
         @Override
         public void mousePressed(MouseEvent evt) {
            tAreaMousePressed(evt);
         }
      });
   }

   private void tAreaMousePressed(MouseEvent evt) {
      try {
         int offset = tArea.viewToModel(evt.getPoint());
         Rectangle rect = tArea.modelToView(offset);

         int startRow = tArea.viewToModel(new Point(0, rect.y));
         int endRow = tArea.viewToModel(new Point(tArea.getWidth(), rect.y));
         
         System.out.printf("Selected Offsets: [%d, %d]%n", startRow, endRow);
         
         tArea.select(startRow, endRow);
      } catch (BadLocationException e) {
         e.printStackTrace();
      }
   }

   private static void createAndShowUI() {
      JFrame frame = new JFrame("HighlightTextAreaLine");
      frame.getContentPane().add(new HighlightTextAreaLine());
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      java.awt.EventQueue.invokeLater(new Runnable() {
         public void run() {
            createAndShowUI();
         }
      });
   }

}

[misiom1]

Thanks for the link, I've just found it a few minutes ago and already implemented, it works perfectly !