[question] How to use android-ndk (android_ndk_installer) in combination with classic CMake projects

[andioz]

Hi all,

I apologize for this very basic question, but I'm stuck and cannot find good documentation for solving my problem. Therefore I ask it here, maybe this is of interest for other developers too.

A sample project is here: hello-world.zip

I have a (quite large) project with CMake. I use conan of course, and typically I run conan export (for local recipes) and conan install from inside CMakeLists.txt. To simplify that let's say I run conan install before running CMake here:

conan install . -if build/linux-old -b missing -pr linux_profile

# linux_profile

include(default)

[settings]
compiler.libcxx=libstdc++11

[options]
[env]

# conanfile.py

import conans


class ProjectConan(conans.ConanFile):
    settings = "os", "compiler", "build_type", "arch"
    generators = "cmake"

    requires = (
        "gtest/1.10.0"
    )

    default_options = (
        "gtest:shared=False"
    )

Then I run cmake, in CMakeLists.txt I use the typical Conan includes and functions:

cmake --build build/linux-old

# CMakeLists.txt

cmake_minimum_required(VERSION 3.18)
project(hello-world CXX)

include(${CMAKE_BINARY_DIR}/conanbuildinfo.cmake)
conan_basic_setup(TARGETS)

add_executable(${PROJECT_NAME} main.cpp)
target_link_libraries(${PROJECT_NAME} CONAN_PKG::gtest)

After that, building works an everything is fine for the Linux host platform. This is my happy path.

---

Now, I want to use the same project for Android. I use the old android_ndk_installer first because this is my current setup, but I want to change to the newer version when I've solved this one. Anyway it's included in the examples too (using the new build/host profile setup).

What I don't understand: all information for the NDK (ANDROID_ABI and CMAKE_TOOLCHAIN_FILE) is known by the android_ndk_installer, and I want to use this information. But how? I think I have to run now this commands, where I add the values for both settings to the CMake command line:

conan install . -if build/android-old -b missing -pr android_profile
cmake -B build/android-old \
  -D ANDROID_ABI=arm64-v8a \
  -D CMAKE_TOOLCHAIN_FILE=/home/zoufala/.conan/data/android_ndk_installer/r20/bincrafters/stable/package/84fc5086d5b84ea42507b9623275f83e74452fe1/build/cmake/android.toolchain.cmake

At least, it is what I do currently, with this hard-coded settings.

# android_profile

include(default)

[settings]
arch=armv8
compiler=clang
compiler.libcxx=libc++
compiler.version=8
os=Android
os.api_level=21

[build_requires]
android_ndk_installer/r20@bincrafters/stable

[options]
[env]

As you can see, I have to know the values for ANDROID_ABI and CMAKE_TOOLCHAIN_FILE here, but how to get it from android_ndk_installer?

I cannot change the project setup too much, because it is big and has many other constraints. But I hope there is a simple solution for this?

Is there a more detailed documentation you can recommend to me? https://docs.conan.io/en/latest/integrations/cross_platform/android.html doesn't explain much, just In case of using CMake, it will inject the appropriate toolchain file and set up the necessary CMake variables.

Many thanks in advance!

[andioz]

I created a repo with the example code: https://github.com/andioz/conan-cmake-multiplatform

[andioz]

I found an interesting issue: conan-io/conan#2956

Would be the usage of virtualenv and/or CMakeToolchain generators be the way to go?