问题
I am signing a pdf file with iText. When I view the file on Acrobat Reader 9, the green tick does not appear inside the signature rectangle as it used to do in Acrobat Reader 7.
Note that I can see the validity mark on top of the page, but I specifically want the mark to appear in the signature rectangle.
Some say that this feature is no longer supported by Acrobat by version 9, however I have viewed some digitally signed files with the green check mark on version 9.
So, is there a specific flag or layer on itext I need to use? I already use setAcro6Layers, setVisibleSignature, setLayer2Text, setLayer2Font, setImage, setImageScale etc..
Any help is much appreciated. thanks

回答1:
it turns out I only needed to set Acro6Layers to false and not set any image with setImage method... instead of setImage, I used setSignatureGraphic method...
pdfSignatureAppearance.setAcro6Layers(false);
pdfSignatureAppearance.setImage(null);
pdfSignatureAppearance.setSignatureGraphic(Image...);
回答2:
pdfSignatureAppearance.setAcro6Layers(true);
pdfSignatureAppearance.setImage(null);
using itext-2.1.7.jar
来源:https://stackoverflow.com/questions/10755989/pdf-signature-validity-check-mark-not-visible-on-acrobat-reader