Here is a place that tells you how to get started:http://mobile.tutsplus.com/tutorials/an ... -tutorial/
Here are my notes on doing it on Windows:
Compiling NDK code with CygWin
If you decide to add native code to your project. Here's briefly how to compile the c/c++ files. You
seem to have to know a lot of stuff about Linux. Sort of like entering a time machine as Cygwin's
command line greets you. By the way, on Windows, Cygwin is necessary.
Make sure your ndk directory is very close to the root (c:\) and has no spaces in the path to it.
Place your entire Android project in the ndk directory. Example: c:\ndk\projectdir
Place the necessary c source files in a folder called jni along with the make file for this code
in a file called Android.mk in the same folder which should contain something like this:
LOCAL_PATH := $(call my-dir)
#LOCAL_PATH := ./jni alternative path
LOCAL_LDLIBS := -llog
LOCAL_MODULE := first
LOCAL_SRC_FILES := source_code_filename.c
Start CygWin and set the environment string to use cygwin's make.exe.
Mine is like this: export GNUMAKE=/cygdrive/c/cygwin/bin/make.exe
Navigate to project by entering this: cd /cygdrive/c/ndkdir/projectdir
Use the path to the ndk-build executable to build the native code.
Mine is like this: /cygdrive/c/ndk/ndk6/ndk-build
If you get an error check all spelling and caps till you find something wrong.
Hope this helps.