So I have built this project based on a pdf reader(MuPDF). I used ndk-build for that. The name of this project is ChoosePDFActivity. I know that it has been correctly built
You just have to create a dummy dynamic library that simply links against your static library like this:
https://stackoverflow.com/a/2957386/892714
The ndk build system (unfortunately) will not create a static library without it being used by a dynamic library. Then you simply grab your static library from obj/local/armeabi-v7a.