Automatically Scrolling Down in a JTextArea (CodingClues)

Jun
22

Automatically Scrolling Down in a JTextArea

MarkusJava

There are some cases where you want a text field to automatically scroll down, e.g. for a log window. The following code snippet will make the JTextArea (embedded in a JScrollPane) scroll down automatically when the scroll position is at the bottom before adding the text:

// Determine whether the scrollbar is currently at the very bottom position.
JScrollBar vbar = scrollPane.getVerticalScrollBar();
boolean autoScroll = ((vbar.getValue() + vbar.getVisibleAmount()) == vbar.getMaximum());

// append to the JTextArea (that’s wrapped in a JScrollPane named ’scrollPane’
area.append( “blah blah\n“ );

// now scroll if we were already at the bottom.
if( autoScroll ) area.setCaretPosition( area.getDocument().getLength() );

Thanks Udo Schuermann from the Java Forums.

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Viewing 1 Comment

Halil 11/26/2008 07:19 PM 2 points
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This is not automatic scrolling. this is programatic scrolling. This should be controlled through a boolean property of the component. But as far as I know, Swing API does not support this.

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