Make the pdf readonly

How do I make my pdf readonly in the SDK?

What do you mean?
If you are using Premium or Master you're allowed to save the pdf as new document with password protection.

Yes, I have the premium license. How do I generate a new PDF file protected by password?

I explain better:
I have a PDF file with some form fields that I am currently filling with the Android SDK in an app of mine (see the attached image as example).
The filling with the SDK goes well, but after that I need to "lock" the PDF in such a way that is no more editable by anyone, just viewable (i.e. make it readonly).
Ho do I achieve that?

 

The best way is to flatten the page: it substitutes annotations with elements glued on the page.

OK, could you please tell me how to do that with the Android SDK?