更改iText中复选框字段的外观

Question

I need to be able to customize the checkbox fill type on demand as I render the pdf.

I must do this only with the AcroFields (pdfStamper.getAcroFields()), because I'm not creating any new fields (just modifying), and that's the only thing I have available to me in scope. I have tried about a hundred things, including the one listed below, which was my best guess on how to do this.

  PdfDictionary dictionary = (PdfDictionary)  acrofields.getFieldItem("ABCD").getWidget(0).get(PdfName.MK);
  dictionary.put(PdfName.CA, new PdfString("8", PdfObject.TEXT_UNICODE));

ABCD is just for testing.

I am very stuck, and any help would be greatly appreciated. I am able to change the value in the dictionary, but it does not seem to have any affect when I write the pdf to a file. Other changes such as setting the checkbox to being checked/unchecked work, as well as populating text fields. So I as very surprised and confused why this is not working.

Answer 1

You're trying to change the caption of a check box, but it's unclear to me what you expect to see. Do you want to see the text "8"? In that case, changing the caption isn't sufficient. You also need to change the appearance. You can find the possible appearances under the /AP key. In the case of a check box, you'll find two possible appearance states under the normal appearance ( /N ). These XObjects define what you see when the PDF is rendered.