The OpenCV Java API and C++ API are both relevant to Android. The Java API documentation is online at http://docs.opencv.org/java/, and an index of OpenCV4Android resources is online at http://opencv.org/platforms/android.html. The C++ API documentation is online at http://docs.opencv.org/. The following documents, which mostly use C++ code, are also available as downloadable PDF files:
API reference: http://docs.opencv.org/opencv2refman.pdf
Tutorials: http://docs.opencv.org/opencv_tutorials.pdf
User guide (incomplete): http://docs.opencv.org/opencv_user.pdf
If the documentation does not seem to answer your question, try talking to the OpenCV community. Here are some sites where you will find helpful people:
Official OpenCV forum: http://www.answers.opencv.org/questions/
Jay Rambhia's blog: http://jayrambhia.wordpress.com/
The support site for my OpenCV books: http://nummist.com/opencv/
Also, you can read or submit bug reports at http://code.opencv.org/projects/opencv/issues?query_id=4. Finally, if you need to take your issue to the highest authority, you can e-mail the OpenCV4Android developers at <[email protected]>.