Android Project and NDK (Kotlin)

This project is just the setup for the NDK in android, the communication Android project with C/C++ file. In this example we print only a text from C/C++ file to Android Project.

Similar project with (Dart Language)

https://github.com/NicosNicolaou16/FlutterAndroidProjectAndNDK

Setup - Steps

• Install the latest NDK and CMake version from Android Studio SDK Manager from the SDK Tools section.
• Create the cpp package, add the CMake .txt and .cpp file. Some name below is base on .cpp file name.

# For more information about using CMake with Android Studio, read the
# documentation: https://d.android.com/studio/projects/add-native-code.html

# Sets the minimum version of CMake required to build the native library.

cmake_minimum_required(VERSION 3.4.1)

# Creates and names a library, sets it as either STATIC
# or SHARED, and provides the relative paths to its source code.
# You can define multiple libraries, and CMake builds them for you.
# Gradle automatically packages shared libraries with your APK.

add_library( # Sets the name of the library.
        message # based on .cpp file name

        # Sets the library as a shared library.
        SHARED

        # Provides a relative path to your source file(s).
        message.cpp) # based on .cpp file name

# Searches for a specified prebuilt library and stores the path as a
# variable. Because CMake includes system libraries in the search path by
# default, you only need to specify the name of the public NDK library
# you want to add. CMake verifies that the library exists before
# completing its build.

find_library( # Sets the name of the path variable.
        log-lib

        # Specifies the name of the NDK library that
        # you want CMake to locate.
        log)

# Specifies libraries CMake should link to your target library. You
# can link multiple libraries, such as libraries you define in this
# build script, prebuilt third-party libraries, or system libraries.

target_link_libraries( # Specifies the target library.
        message # based on .cpp file name

        # Links the target library to the log library
        # included in the NDK.
        ${log-lib})

• Add the follow code in Gradle file.

android {

    //Other Gradle Code Here...

    externalNativeBuild {
        cmake {
            path = file("src/main/cpp/CMakeLists.txt")
            version = "3.22.1"
        }
    }
    ndkVersion = "26.1.10909125"

    //Other Gradle Code Here...
}

• Load the C/C++ file.

companion object {
    /**
     * Load the C file
     * */
    init {
        System.loadLibrary("message")
    }
}

• Initialize the method(s) from .cpp file.

private external fun message(): String 

Check my article

https://medium.com/@nicosnicolaou/ndk-setup-on-android-flutter-android-project-1571d9a3f5cb

References/Tutorials Follow

https://github.com/android/ndk-samples
https://developer.android.com/studio/projects/add-native-code
https://blog.mindorks.com/getting-started-with-android-ndk-android-tutorial/

Versions

Target SDK version: 34
Minimum SDK version: 27
Kotlin version: 1.9.23
Gradle version: 8.4.0