You can access PDFNet with the same C/C++ interface from all platforms (Android, iOS, WinRT, etc). The SDK comes with the C/C++ Headers (it is inside the Headers folder in the zip file) and you would be looking at C/C++ samples (http://www.pdftron.com/pdfnet/samplecode.html) rather than Java. You can also find most of documentation (for different platforms) online: http://www.pdftron.com/pdfnet/documentation.html.
If you are looking for a PDF viewer solution we recommend using the PDFViewCtrl (http://www.pdftron.com/pdfnet/mobile/Javadoc/pdftron/PDF/PDFViewCtrl.html), which is a control created specifically for this objective