Include multiple library dependency in same project JNI

Question

I'm trying to build an android app using JNI. The following is my C++ code structure:

main
  -cpp
    -native-lib.cpp
    -dependency.h
    -dependency.cpp

In my native-lib.cpp I'm including dependency.h . In my Cmake, I'm creating a shared library (.so) for dependency and native-lib so that I can load them in my Java part of the code.

While building the code however I cannot build native-lib because it has a dependency on dependency . For a quick fix, I'm building the dependency first and then linking it to native-lib and then loading the two in my java side. But I know it is the wrong way of doing things, hence I wanted to know the right way of adding multiple dependencies in JNI.

The following is my Cmake:

cmake_minimum_required(VERSION 3.4.1)
include_directories(Include)
add_library( # Sets the name of the library.
        dependency

        # Sets the library as a shared library.
        SHARED

        # Provides a relative path to your source file(s).
        dependency.cpp )

add_library( # Sets the name of the library.
        native-lib

        # Sets the library as a shared library.
        SHARED

        # Provides a relative path to your source file(s).
        native-lib.cpp )

# Once the so is being built I'm adding it myself and linking it. 
# I don't want to do this but link it automatically
target_link_libraries( # Specifies the target library.
        native-lib

        # Links the target library to the log library
        # included in the NDK.
        ${CMAKE_CURRENT_SOURCE_DIR}/../jniLibs/armeabi-v7a/libdependency.so)

Here is the Java code:

public class MainActivity extends AppCompatActivity {

    // Used to load the 'native-lib' library on application startup.
    static {
        System.loadLibrary("dependency");
        System.loadLibrary("native-lib");
    }
    
    // Some other functions
}

PS: Not adding target_link_libraries to link libdependency.so thinking that Java LoadLibrary will link it in real-time does not build as native-lib would have undefined references

Answer 1

On Android, you only need to explicitly loadLibrary("dependency") if the platform is older than API 21. As for CMake ,

target_link_libraries(native-lib dependency)

should work, but you may need to clean the project if the CMake caches don't get properly updated.