I finally had enough time to look at developing on the Android platform and got my test integration of C++ code with the Android NDK working. The biggest hurdle proved to be familiarity with the Android development environment itself. The following tips apply to NDK 1.6r1:
1) You DO NOT have to have surround your functions with a various extern “C”‘s. Unlike what people are saying out there about having to do it you do not have to do it.
2) Check the names of the class to make sure the packages match your JNI interface. (i.e. if your class with the native interfaces are com.examples.HelloWorld…..your JNI class should be Java_com_examples_HelloWorld_<class>
3) Check your android.xml file for the proper package export. When you refactor/rename things in the Eclipse editor it will not update the package export. This will result in Android not being able to find your JNI interface and complain in logcat.
As of 1.6r1, the NDK is something still to play around with and not really ready for production development. That seems to be way the Google Android teams seems to like to run things. Although the OpenGL ES 1.0 libs are available, other supporting libraries are not (i.e. those to load png or jpg’s for texture. The audio libraries). My initial experiments on writing xPhone with Android has a initial platform would prove daunting to say the least.