如何在Android Studio 1.3.2中包括预构建的.so库

Question

I am having difficulties integrating a native library I have already built using ndk-build into my Android Studio project. The problem is that I am stuck in a transitional period where the Gradle syntax is brand new, but documentation and online help still reference the old syntax.

My library is in this location on my project: app/libs/(armeabi and others)/libsample.so , for a total of 7 variants of the same library for different architectures. I also have the header files for this library in app/src/main/jni/headers , and the C wrapper file which calls functions defined in this library on app/src/main/jni/wrapper.c . The wrapper file has a #include "headers/sample.h" .

The main issue is that I don't know how to set up my Gradle build to use the prebuilt shared library. I have a working Android.mk file which can successfully compile my wrapper to use the shared library, but I can't use it in Android Studio, since Gradle generates it's own makefile and uses that instead. Anyone has any idea how to proceed from here?

Answer 1

You should be able to simply drop the pre-built .so files into (project module)/src/main/jniLibs/(target abi), and they'll be included in the final apk that Android Studio generates.

One caveat : I'm not 100% certain, but it looks like Android's installer can choose to throw out some libraries from abi folders that it decides are a poorer fit for the current device than other abi folders in the apk (ex. armeabi and armeabi-v7a may both be compatible, but armeabi-v7a may be a better fit) if said libraries are only present in the poorer-fit folder. This becomes important if you don't have the source code for the native library. You can work around this either by specifying a single abi in your module's build.gradle (see the answer to the linked question) that matches the abi your native library was compiled for or by disabling Android Studio's ndk-build process by setting jni.srcDirs = [] in android.sourceSets.main