When trying to compile, I came across these two options, in my case only one worked, which led me to the questions:
BUILD_STATIC_LIBRARY or BUILD_SHARED_LIBRARY ? BUILD_SHARED_LIBRARY : This variable points to a build script that collects all information about the module you provided in your LOCAL_XXX variables, and determines how to build a shared library from the sources you've listed. Using this script requires that you have already assigned values to LOCAL_MODULE and LOCAL_SRC_FILES .
BUILD_STATIC_LIBRARY : Used to build a static library. The build system does not copy static libraries to their project/packages , but can use them to build shared libraries.
In this response , explains the difference, advantages and disadvantages of static and dynamic linking.
To learn more about BUILD_STATIC_LIBRARY and BUILD_SHARED_LIBRARY documentation explains and suggests links so you can better understand how they work.