In the previous three chapters, we have covered Android NDK OpenGL ES API (Chapter 4, Android NDK OpenGL ES API), Native Application API (Chapter 5, Android Native Application API), and Multithreading API (Chapter 6, Android NDK Multithreading). This is the last chapter on Android NDK API illustration, and we will cover a few more libraries, including the jnigraphics library, dynamic linker library, zlib compression library, OpenSL ES Audio library, and OpenMAX AL multimedia library.

We first introduce two small libraries, jnigraphics and dynamic linker, which only have a few API functions and are easy to use. We then describe zlib compression library, which can be used to compress and decompress data in .zlib and .gzip formats. The OpenSL ES audio library and OpenMAX AL multimedia library are two relatively new APIs available on newer versions of Android. The API functions in these two libraries are not frozen yet and still evolving. Because the source compatibility is not a goal of the library development on Android, as stated in the NDK OpenSL ES and OpenMAX AL documentation, future versions of these two libraries may require us to update our code.

Also, note that OpenSL ES and OpenMAX AL are fairly complex libraries with lots of API functions. We can only introduce the basic usage of these two libraries with simple examples. Interested readers should refer to the library documentation for more details.