How to underline a portion of text in a text field?

Tags: XML WorkerElementListunderlineXHTMLiText 5

I have an application that uses iText to fill PDF form fields. One of these fields has some text with tags. For example:

<U>This text</U> should be underlined. 
I need the text enclosed in <U>-tag to be underlined. How could I do that?

Posted on StackOverflow on Feb 18, 2015 by Galma88

Ordinary text fields do not support rich text. If you want the fields to remain interactive, you will need RichText fields. These are fields that are flagged in a way that they accept an RV value.

If it is OK for you to flatten the form (i.e. remove all interactivity), please take a look at the FillWithUnderline example:

public void manipulatePdf(String src, String dest)
    throws DocumentException, IOException {
    PdfReader reader = new PdfReader(src);
    PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
    stamper.setFormFlattening(true);
    AcroFields form = stamper.getAcroFields();
    FieldPosition pos = form.getFieldPositions("Name").get(0);
    ColumnText ct = new ColumnText(stamper.getOverContent(pos.page));
    ct.setSimpleColumn(pos.position);
    ElementList elements = XMLWorkerHelper.parseToElementList(
        "<div>Bruno <u>Lowagie</u></div>", null);
    for (Element element : elements) {
        ct.addElement(element);
    }
    ct.go();
    stamper.close();
}

In this example, we don't fill out the field, but we get the fields position (a page number and a rectangle). We then use ColumnText to add content at this position. As we are inputting HTML, we use XML Worker to parse the HTML into iText objects that we can add to the ColumnText object.