适合初学者：
http://www.eoeandroid.com/forum.php?mod=viewthread&tid=264384
http://www.eoeandroid.com/forum.php?mod=viewthread&tid=264543
http://www.eoeandroid.com/thread-264971-1-1.html
强烈推荐此篇 尽管是英文的：
https://thenewcircle.com/s/post/49/using_ndk_to_call_c_code_from_android_apps
