Re: JTextArea contraints

"Michael Dunn" <michael.dunn@THRWHITE.remove-dii-this>
Wed, 27 Apr 2011 15:28:59 GMT
  To: wrote:

I have tried and cont. to limit the rows(lines) on a JTextArea.
I have created a PlainDoc. and have successfully limited the max
The max chars is good for the text area as a whole if you start at 0
and fill every line.
However in this case, which would be a text editor, a vertical limit is

The user can not exceed past row/line 17. As is now, the user can type
past line 17.
Any suggestions on how to limit?

This one's rough - needs a bucket-load of testing

import javax.swing.*;
import java.awt.*;
import javax.swing.text.*;
class Testing
  JTextArea ta = new JTextArea();
  final int MAX_LINES = 5;
  int height;
  public void buildGUI()
    JScrollPane sp = new JScrollPane(ta);
    sp.setPreferredSize(new Dimension(100,100));
    JFrame f = new JFrame();
    height =
    ta.setDocument(new PlainDocument(){
      public void insertString(int offs, String str, AttributeSet a)
throws BadLocationException{
        String oldText = ta.getText();
        super.insertString(offs, str, a);
        if(ta.modelToView(getLength()).y > height)
  public static void main(String[] args)
    SwingUtilities.invokeLater(new Runnable(){
      public void run(){
        new Testing().buildGUI();

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