Question

So, I have JTextArea on a JPanel (BoxLayout). I also have Box filler that fills the rest of the JPanel. I need my JTextArea to start of with single-line-height (I can manage that), and to expand and reduce when that is needed.

Word wrap is enabled, I just need it to adjust it’s height when new line is added/removed.

I tried with documentListener and getLineCount(), but it doesn’t recognize wordwrap-newlines.

I’d like to avoid messing with the fonts if it’s possible.

And, NO SCROLL PANES. It’s essential that JTextArea is displayed fully at all times.

Answer 1

JTextArea has a rather particular side effect, in the right conditions, it can grow of it’s own accord. I stumbled across this by accident when I was trying to set up a simple two line text editor (restricted characters length per line, with a max of two lines)…

Basically, given the right layout manager, this component can grow of it’s own accord – it actually makes sense, but took me by surprise…

Now in addition, you may want to use a ComponentListener to monitor when the component changes size, if that’s what you’re interested…

public class TestTextArea extends JFrame {

    public TestTextArea() {

        setLayout(new GridBagLayout());

        JTextArea textArea = new JTextArea();
        textArea.setColumns(10);
        textArea.setRows(1);
        textArea.setLineWrap(true);
        textArea.setWrapStyleWord(true);

        add(textArea);

        setSize(200, 200);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);

        textArea.addComponentListener(new ComponentAdapter() {

            @Override
            public void componentResized(ComponentEvent ce) {

                System.out.println("I've changed size");

            }

        });

    }


    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new TestTextArea();
    }

}