Android Native Development Kit (NDK)
The latest version of this document is available at https://android.googlesource.com/platform/ndk/+/master/README.md.
Note: This document is for developers of the NDK, not developers that use the NDK.
The NDK allows Android application developers to include native code in their Android application packages, compiled as JNI shared libraries.
This doc gives a high level overview of the NDK's build, packaging, and test process. For other use cases, or more in depth documentation, refer to the following sources:
- User documentation is available on the Android Developer website.
- Adding a new NDK API or platform version? Check Generating Sysroots.
- Working on Clang or GCC? See Toolchains.md.
- Discussions related to the Android NDK happen on the android-ndk Google Group.
- File bugs against the NDK at https://github.com/android-ndk/ndk/issues.
Building the NDK
Both Linux and Windows host binaries are built on Linux machines. Windows host
binaries are built via MinGW cross compiler. Systems without a working MinGW
compiler can use
build/tools/build-mingw64-toolchain.sh to generate their own
and be added to the
PATH for build scripts to discover.
Building binaries for Mac OS X requires at least 10.8.
Target headers and binaries are built on Linux.
The NDK consists of three parts: host binaries, target prebuilts, and others (build system, docs, samples, tests).
toolchains/contains GCC and Clang toolchains.
$TOOLCHAIN/config.mkcontains ARCH and ABIS this toolchain can handle.
$TOOLCHAIN/setup.mkcontains toolchain-specific default CFLAGS/LDFLAGS when this toolchain is used.
prebuilt/$HOST_TAGcontains build dependencies and additional tools.
- make, awk, python, yasm, and for Windows: cmp.exe and echo.exe
ndk-gdbcan also be found here.
Target Headers and Binaries
platforms/android-$VERSION/arch-$ARCH_NAME/contains headers and libraries for each API level.
- The build system sets
--sysrootto one of these directories based on user-specified
- The build system sets
sources/cxx-stl/$STLcontains the headers and libraries for the various C++ STLs.
build/contains the ndk-build system and scripts to rebuild NDK.
sources/third_partycontain modules that can be used in apps (cpufeatures, native_app_glue, etc) via
$(call import-module, $MODULE)
Check out the branch
repo init -u https://android.googlesource.com/platform/manifest \ -b master-ndk # Googlers, use repo init -u \ persistent-https://android.git.corp.google.com/platform/manifest \ -b master-ndk
Additional Linux Dependencies (available from apt):
- pbzip2 (optional, improves packaging times)
- python3 (used for Vulkan validation layer generation)
- python-lxml (used for Vulkan validation layer generation)
Mac OS X also requires Xcode.
For Linux or Darwin:
$ python checkbuild.py
For Windows, from Linux:
$ python checkbuild.py --system windows # Or windows64.
checkbuild.py also accepts a variety of other options to speed up local
checkbuild.py will also package the NDK and run basic tests. To
skip the packaging step, use the
--no-package flag. Note that running the
tests does require the packaging step.
If you need to re-run just the packaging step without going through a build,
packaging is handled by
Testing is discussed in Testing.md.