this is an example of searching a word and adding annotation to it:
Page currentPage = m_doc.GetPage(page);
currentPage.ObjsStart();
String str = "radaee";
Finder mFinder = currentPage.FindOpen(str, false, false);
if( mFinder != null ) {
int ichar = mFinder.GetFirstChar(0);
int ichar_end = ichar + str.length() - 1;
float rect[] = new float[4];
float rect_end[] = new float[4];
currentPage.ObjsGetCharRect(ichar, rect);
currentPage.ObjsGetCharRect(ichar_end, rect_end);
//currentPage.AddAnnotMarkup(ichar, ichar_end, 0);
currentPage.AddAnnotURI(new float[]{rect[0], rect[1], rect_end[2], rect_end[3]}, "http://www.androidpdf.mobi");
//rerender the page to see the annotation
}
