ndk

NDK stands for the Android Native Development Kit. It is a toolset that enables developers to implement parts of an Android app using native code written in C or C++. The NDK provides a compiler toolchain, headers, libraries, and build utilities that run on Windows, macOS, and Linux. It is intended for performance-critical components and for porting existing native libraries to Android. Java and Kotlin code continue to run in the Android runtime, while native code is accessed from Java/Kotlin via the Java Native Interface (JNI).

Core components of the NDK include a Clang-based compiler toolchain, a collection of native system libraries, and two primary build systems: CMake and ndk-build. The kit also supplies headers for the Android platform and prebuilt binaries for multiple architectures. The toolchain produces shared libraries (.so) that are packaged into APKs or Android App Bundles and accessed by the app at runtime.

Development workflow typically involves writing native code, configuring a build script (CMakeLists.txt or Android.mk), compiling the code for selected ABIs (such as armeabi-v7a, arm64-v8a, x86_64, x86), generating a .so, and calling into it from Java or Kotlin through JNI. The Android Gradle Plugin supports externalNativeBuild to integrate NDK builds into Android Studio projects.

History and status: The NDK originated in the late 2000s and has evolved toward Clang-based toolchains and CMake. While ndk-build remains for compatibility, CMake is the recommended, more versatile option for new projects. The NDK is updated periodically with new API levels and architectures.

Use cases and considerations: it is commonly used for graphics engines, game engines, and performance-focused libraries, as well as porting legacy C/C++ code. Limitations include increased complexity, platform-specific bugs, larger binary sizes, and maintenance overhead. Licensing and compatibility with Android API levels should be reviewed.