How to change Install Dir when Building OpenCV 3.1.0 on Ubuntu 18.04 for Android NDK18rc and ARMEABI-7?

Question

I am trying for over one week to compile OpenCV 3.1.0 for Android with NDK r18 on Ubuntu 18.04.

I have used the following command:

cmake -DCMAKE_BUILD_WITH_INSTALL_RPATH=ON \
  -DANDROID_NDK="/home/qamaruddin/Downloads/android-ndk-r18-linux-x86_64/android-ndk-r18/" \
  -DCMAKE_TOOLCHAIN_FILE="/home/qamaruddin/Downloads/android-ndk-r18-linux-x86_64/android-ndk-r18/build/cmake/android.toolchain.cmake" \
  -DANDROID_NATIVE_API_LEVEL=19 \
  -DANDROID_ABI="armeabi-v7a" \
  -DWITH_CUDA=OFF \
  -DWITH_MATLAB=OFF \
  -DBUILD_ANDROID_EXAMPLES=OFF \
  -DBUILD_DOCS=OFF \
  -DBUILD_PERF_TESTS=OFF \
  -DBUILD_TESTS=OFF \
  -DCMAKE_CXX_COMPILER=/usr/bin/clang++ \
  -DCMAKE_C_COMPILER=/usr/bin/clang \
  -DOPENCV_EXTRA_MODULES_PATH="/opt/opencv_contrib/modules/"  \
  -DCMAKE_INSTALL_PREFIX:PATH="/home/mig-ocv/ocv-android-310/" \
  -DEXECUTABLE_OUTPUT_PATH:PATH="/home/mig-ocv/ocv-android-310/" \
  -DCMAKE_RUNTIME_OUTPUT_DIRECTORY:PATH="/home/mig-ocv/ocv-android-310/" \
  -DCMAKE_BUILD_TYPE=Release \
  /opt/opencv

Follwed by make & make install/strip.

I have tried different versions of OpenCV 3 such as 3.1.0, 3.4.3, and 3.4.0. I have also tried NDKr15c, NDKr17c, and NDKr18c.

I have tried the following variations:

1. Change NDK version
2. Change OpenCV 3 version
3. Install using python script located at opencv/platforms/androind/setup.py
4. Build using CMAKE
5. Use Ninja for CMAKE, but this gives the error: "ninja: error: loading 'build/build.global.ninja': No such file or directory"
6. Install without Ninja with CMAKE

At the moment, using the above-posted command for CMAKE builds successfully, but I can't change the target install dir since it always builds into /usr/local/ and when I inspect the target directory it does not have the familiar OpenCV for Android structure which is:

1- etc 2- java 3- native --> jni --> include

I wonder what is wrong in my process that makes it so difficult to build OpenCV 3 from source for Android with OpenCV Contrib.

Note that $ANDROID_HOME is set to the android SDKs directory on my system and $ANDROID_NDK is also set.

I have seen all duplicate questions on StackOverflow and other forums, but none seems to work in my case.

When I try to build with Ninja with this command:

cmake -DCMAKE_BUILD_WITH_INSTALL_RPATH=ON \
  -DANDROID_NDK="$HOME/Downloads/android-ndk-r17b/" \
  -DCMAKE_TOOLCHAIN_FILE="$HOME/Downloads/android-ndk-r17b/build/cmake/android.toolchain.cmake" \
  -DANDROID_NATIVE_API_LEVEL=21 \
  -DANDROID_ABI="armeabi-v7a" \
  -DWITH_CUDA=OFF \
  -DWITH_MATLAB=OFF \
  -DBUILD_ANDROID_EXAMPLES=OFF \
  -DBUILD_DOCS=OFF \
  -DBUILD_PERF_TESTS=OFF \
  -DBUILD_TESTS=OFF \
  -DCMAKE_CXX_COMPILER=/usr/bin/clang++ \
  -DCMAKE_C_COMPILER=/usr/bin/clang \
  -DOPENCV_EXTRA_MODULES_PATH="$HOME/ocv/opencv_contrib/modules/"  \
  -DCMAKE_INSTALL_PREFIX:PATH="$HOME/agusta/ocv-android-310/" \
  -DEXECUTABLE_OUTPUT_PATH:PATH="$HOME/agusta/ocv-android-310/" \
  -DCMAKE_RUNTIME_OUTPUT_DIRECTORY:PATH="$HOME/agusta/ocv-android-310/" \
  -DCMAKE_BUILD_TYPE=Release \
  -DCMAKE_MAKE_PROGRAM=/usr/bin/ninja \
  $HOME/ocv/opencv

I get:

CMake Deprecation Warning at CMakeLists.txt:72 (cmake_policy):


The OLD behavior for policy CMP0022 will be removed from a future version
  of CMake.

  The cmake-policies(7) manual explains that the OLD behaviors of all
  policies are deprecated and that a policy should be set to OLD only under
  specific short-term circumstances.  Projects should be ported to the NEW
  behavior and not rely on setting a policy to OLD.


CMake Deprecation Warning at CMakeLists.txt:77 (cmake_policy):
  The OLD behavior for policy CMP0026 will be removed from a future version
  of CMake.

  The cmake-policies(7) manual explains that the OLD behaviors of all
  policies are deprecated and that a policy should be set to OLD only under
  specific short-term circumstances.  Projects should be ported to the NEW
  behavior and not rely on setting a policy to OLD.


CMake Deprecation Warning at CMakeLists.txt:82 (cmake_policy):
  The OLD behavior for policy CMP0042 will be removed from a future version
  of CMake.

  The cmake-policies(7) manual explains that the OLD behaviors of all
  policies are deprecated and that a policy should be set to OLD only under
  specific short-term circumstances.  Projects should be ported to the NEW
  behavior and not rely on setting a policy to OLD.


-- Check for working CXX compiler: /home/qamaruddin/Downloads/android-ndk-r17b/toolchains/llvm/prebuilt/linux-x86_64/bin/clang++
CMake Error: Generator: execution of make failed. Make command was: "/usr/bin/ninja" "cmTC_c4cee/fast"
-- Check for working CXX compiler: /home/qamaruddin/Downloads/android-ndk-r17b/toolchains/llvm/prebuilt/linux-x86_64/bin/clang++ -- broken
CMake Error at /usr/local/share/cmake-3.12/Modules/CMakeTestCXXCompiler.cmake:45 (message):
  The C++ compiler

    "/home/qamaruddin/Downloads/android-ndk-r17b/toolchains/llvm/prebuilt/linux-x86_64/bin/clang++"

  is not able to compile a simple test program.

  It fails with the following output:

    Change Dir: /home/qamaruddin/agusta/temp/CMakeFiles/CMakeTmp

    Run Build Command:"/usr/bin/ninja" "cmTC_c4cee/fast"
    No such file or directory
    Generator: execution of make failed. Make command was: "/usr/bin/ninja" "cmTC_c4cee/fast"




  CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
  CMakeLists.txt:93 (project)


-- Configuring incomplete, errors occurred!
See also "/home/qamaruddin/agusta/temp/CMakeFiles/CMakeOutput.log".
See also "/home/qamaruddin/agusta/temp/CMakeFiles/CMakeError.log".
You have changed variables that require your cache to be deleted.
Configure will be re-run and you may have to reset some variables.
The following variables have changed:
CMAKE_CXX_COMPILER= /usr/bin/clang++
CMAKE_C_COMPILER= /usr/bin/clang

-- Generating done
CMake Warning:
  Manually-specified variables were not used by the project:

    BUILD_ANDROID_EXAMPLES
    BUILD_DOCS
    BUILD_PERF_TESTS
    BUILD_TESTS
    EXECUTABLE_OUTPUT_PATH
    OPENCV_EXTRA_MODULES_PATH
    WITH_CUDA
    WITH_MATLAB


-- Build files have been written to: /home/qamaruddin/agusta/temp

Answer 1

I have managed to get it to work, basically, OCV didn't support NDKr18, and I also had to install ninja from source. I have also used python3 instead of python2 to run the opencv/platforms/android/build_sdk.py . One more thing is that I use Eclipse Android ADT which Google has for no reason deprecated ;(, but I find it super fast compared to the heavy Android Studio.

# export ANDROID_ABI=armeabi-v7a
# export ANDROID_TOOLCHAIN_NAME=arm-linux-androideabi-4.8
# export ANDROID_NDK=$HOME/Downloads/android-ndk-r17c-linux-x86_64/android-ndk-r17c/
# export ANDROID_SDK=$HOME/android-sdks/

./../opencv/platforms/android/build_sdk.py --extra_modules_path=/opt/opencv_contrib/modules --config ../opencv/platforms/android/ndk-17.config.py