i just wanted to tell you: on Nexus10 the event onDoubleTap in PDFView.PDFGestureListener is never triggered.
Tested on Nexus7 and Nexus5, there it worked.
if anybody happens to step into this 'issue':
under settings, accessibility, magnification gestures: if triple-tap-zoom is activated, double-tap-gestures are not detected with the gesture-listener.