I added one snipet to source (demo) code and changed manifest file to handle configchanges:
In ReaderController:
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
m_save_w = w;
m_save_h = h;
if (m_pdv != null && !m_lock_resize)
m_pdv.vResize(w, h);
//added this part
if (m_pdv == null) return;
PDFView.PDFPos pos = m_pdv.vGetPos(0, 0);
m_pdv.vResize(w, h);
m_pdv.vSetScale(0, 0, 0);
if (m_cur_page >= 0) {
m_pdv.vGotoPage(m_cur_page);
} else if (pos != null) {
m_pdv.vSetPos(pos, 0, 0);
m_pdv.vCenterPage(pos.pageno);
}
}
And in manifes.xm for activity displaying pdf I added:
android:configChanges="orientation|screenSize"