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Message:

Re: auto scrolling JTextArea in SWING

Posted by Dave on February 13, 2002 at 10:56 AM

There is a very simple way to force the scroll pane to
scroll down after appending a string to the text.
The point is that the text area is scrolled down after You call
jTextArea.setText( textString ).

So just use:

jTextArea.append( string ); // append the string You want to
jTextArea.setText( jTextArea.getText() );

The second line does not change the text in the text area but
it forces the scroll pane to scroll down the text area.

You can also use

jTextArea.setText( jTextArea.getText() + string );

which is a little bit more effective than the two lines above.

Regards,

Dave

> Move the JScrollPane's vertical scrollBar down after appending the String:

> _pane.getVerticalScrollBar().setValue(_logText.getHeight() - _logText.getVisibleRect().height );

>
> > I have exactly the same problem, and I have found an answer yet.
> > I have been looking around for a week, but still not found a correct solution.
> > My solution is:
> > private void addText(String s) {
> > _logText.append(s);

> > _logText.getCaret().setDot( _logText.getText().length() );
> > _pane.scrollRectToVisible(_logText.getVisibleRect() );

> > this.paint(this.getGraphics()); // should use "paintImmediately" but not usable for JDialog in 1.2 (should be in 1.3)
> > }

> > where _logText is the JTextArea and and _pane is the JScrollPane using _logText.
> > However this solution is not ideal as it is only scrolling when all the inserts in the JTextArea are finished.
> > If any one has a correct solution, let me know.

> > > Hi,

> > > In the AWT if I create a TextArea and then keep feeding information to that
> > > TextArea, it scrolls automatically to show me to most recently appended text
> > > in the component. However if use the swing equivalent, JTextArea this
> > > doesn't happen even if I wrap this class in a JScrollPane. It does bring up
> > > the scrollbar when text gets too much to fit in the window, but it doesn't
> > > automatically scroll down to show me the latest added text.

> > > Is there anyway I can change this?

> > > Thanks a lot,
> > > Russell