sample_of_cross_compile_dlib_for_android_with_cmake.sh

# Step 1. Switch to the release commit. For example: v19.4.
git checkout v19.4

# Step 2. Create the build folder for storing generated files.
cd dlib && mkdir build-armeabi-v7a && cd build-armeabi-v7a;

# Step 3. Use CMake to generate the Makefile.
# -DCMAKE_INSTALL_PREFIX                    Because it's a cross-compiled library. You probably
#                                           want to install the header files and shared library
#                                           in specific folder rather than default /usr/local 
#                                           directory.
# -DANDROID_STL=c++_shared                  For the library using C++11, link to C++11 runtime.
# -DANDROID_LINKER_FLAGS="-landroid -llog"  For the library using functions of libandroid.so
#                                           and liblog.so.
# -DANDROID_CPP_FEATURES="rtti exceptions"  Most ppl use exception and runtime-type-information 
#                                           features in their C++ projects.
#
# Debug Tips:
# Add -LAH to see variables.
$CMAKE \
    -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_TOOLCHAIN_FILE=/<your_toolchain_config_path>/android.toolchain.cmake \
    -DCMAKE_INSTALL_PREFIX=/<your_install_path>/dlib \
    -DANDROID_NDK=/Users/<your_user_name>/Library/Android/sdk/ndk-bundle \
    -DANDROID_TOOLCHAIN=clang \
    -DANDROID_ABI=armeabi-v7a \
    -DANDROID_NATIVE_API_LEVEL=16 \
    -DANDROID_LINKER_FLAGS="-landroid -llog" \
    -DANDROID_STL=c++_shared \
    -DANDROID_CPP_FEATURES="rtti exceptions" \
    ..

# Step 4. Build by the given generated Makefile.
$CMAKE --build .

# Step 5 (optional). Install the library.
make install