I am creating a PDF document of multiple pages using iText. I am adding some unique text on one of the pages in the middle of this document but making it invisible as-
Chunk chunk = new Chunk("invisible text here");
chunk.setTextRenderMode(PdfContentByte.TEXT_RENDER_MODE_INVISIBLE, 0f, null);
com.lowagie.text.Document iTextDoc.add(new Paragraph(Element.ALIGN_JUSTIFIED, chunk));
The reason for adding this invisible text is to identify this particular page at the time of onEndPage(). But it is failing.
To achieve in the onEndPage(), I have the following code -
boolean b = (pdfWriter.getDirectContent().toString()).contains("invisible text here");
I get the value of b as false.
If I compare any other text on that page(which is visible) results b as true.
I tried to manually search the invisible text in the PDF reader and it finds the text.
What could I modify to achieve this?
It is never a good idea to assume you can recognize text in the content without elaborate parsing. The text may be split into multiple segments, encoding might not be platform's default character encoding, etc... Thus don't try something like
boolean b = (pdfWriter.getDirectContent().toString()).contains("invisible text here");
You can achieve your goal
The reason for adding this invisible text is to identify this particular page at the time of onEndPage().
much more easily. Simply add a member to your PdfPageEvent implementation, i.e. the class with your onEndPage() method, and set it where you used to add the invisible page content to the text you used to add to the page.
Now you can test that member variable directly in your onEndPage(). Don't forget to reset the variable afterwards, preferably in onEndPage() itself!