JTextArea: get last line of text

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Aaron Boxer - 29 Sep 2003 15:33 GMT

Hello,

I have subclassed a JTextArea, and am handling the keyboard events.
I would like to get the last line of text each time the user
presses carriage return. I am going to use the widget as a
serial communication terminal: send each line of text over the serial
port after CR.

Any help would be greatly appreciated.

Aaron Boxer

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Daniel Sjöblom - 29 Sep 2003 17:21 GMT

> Hello,
>
[quoted text clipped - 3 lines]
> serial communication terminal: send each line of text over the serial
> port after CR.

Look up getLineOfOffset and getLineEnd/StartOffset in the documentation.

Signature

Daniel Sjöblom

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Bill Tschumy - 29 Sep 2003 17:37 GMT

> Hello,
>
[quoted text clipped - 7 lines]
>
> Aaron Boxer

I haven't compiled this, but this should be pretty close to what you want.

Document document = textArea.getDocument();
Element rootElem = document.getDefaultRootElement();
int numLines = rootElem.getElementCount();
Element lineElem = rootElem.getElement(numLines - 1);
int lineStart = lineElem.getStartOffset();
int lineEnd = lineElem.getEndOffset();
String lineText = document.getText(lineStart, lineEnd - lineStart);

Signature

Bill Tschumy
Otherwise -- Austin, TX
http://www.otherwise.com

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Aaron Boxer - 30 Sep 2003 14:34 GMT

Hi Bill,

thanks for your reply!

I just had to change one line, because of zero offsets:

Element lineElem = rootElem.getElement(numLines - 2);

Cheers,

Aaron

> > Hello,
> >
[quoted text clipped - 17 lines]
> int lineEnd = lineElem.getEndOffset();
> String lineText = document.getText(lineStart, lineEnd - lineStart);

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JTextArea: get last line of text

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