Setup opencv library

• Start the project with native-c++ support. This creates a cpp directory in main directory of the app, containing CMakeLists.txt and native-lib.cpp by default.

• Create a JNI Folder in main directory of app and copy the contents of OpenCV-android-sdk/sdk/native/libs/ into this directory.

• Add the path to opencv sdk to gradle.properties

opencvsdk=/home/user/Downloads/OpenCV-android-sdk

• Create a new opencv directory during build by adding the following lines to settings.gradle

include ':opencv'
project(':opencv').projectDir = new File(opencvsdk + '/sdk')

• Add cmake configs and abi-filters by adding the below lines inside defaultConfig in app-level build.gradle

externalNativeBuild {
        cmake {
            cppFlags "-std=c++17 -frtti -fexceptions"
            abiFilters 'x86', 'x86_64', 'armeabi-v7a', 'arm64-v8a'
            arguments "-DOpenCV_DIR=" + opencvsdk + "/sdk/native"
        }
    }

• Add the opencv directory as a dependency to the application by adding the following lines inside dependencies in the project-level build.gradle

implementation project(path: ':opencv')

• Modify the CMakeLists.txt file to include the opencv library by adding the following lines before existing add_library() section

include_directories(${OpenCV_DIR}/jni/include)
add_library(lib_opencv SHARED IMPORTED)
set_target_properties(lib_opencv PROPERTIES IMPORTED_LOCATION ${OpenCV_DIR}/libs/${ANDROID_ABI}/libopencv_java4.so)

• Add lib_opencv to the target_link_libraries() section.