ndk 编译opencv(去除libandroid.so mediandk依赖)

简单的bash运行

需要关注的：

• OPENCV_EXTRA_MODULES_PATH ： opencv contrib库
• BUILD_opencv_XXX ：添加contrib库后默认是contrib库全部编译，用这个控制需要关闭的
• NDK的路径

export ANDROID_NDK=/media/hello/data/3rd_party/25.2.9519653# rm -rf ndk_build# mkdir ndk_build
cd ndk_buildcmake .. -DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK/build/cmake/android.toolchain.cmake \-DANDROID_ABI="arm64-v8a" \-DANDROID_NDK=$ANDROID_NDK \-DANDROID_PLATFORM=android-29 \-DANDROID_STL=c++_shared \-DOPENCV_EXTRA_MODULES_PATH=/media/hello/data/3rd_party/opencv4.6.0/opencv_contrib/modules \-DBUILD_JAVA=OFF \-DBUILD_FAT_JAVA_LIB=OFF \-DBUILD_ANDROID_EXAMPLES=OFF \-DWITH_ONNX=ON \-Dfreetype_DIR=/media/hello/data/3rd_party_lib/freetype/2.13.2/arm64-v8a/lib/cmake/freetype/ \-DFREETYPE_INCLUDE_DIRS=/media/hello/data/3rd_party_lib/freetype/2.13.2/arm64-v8a/include/freetype2 \-DFREETYPE_LIBRARIES=/media/hello/data/3rd_party_lib/freetype/2.13.2/arm64-v8a/lib/libfreetype.so \-Dharfbuzz_DIR=/media/hello/data/3rd_party_lib/harfbuzz/9.0.0/arm64-v8a/lib/cmake/harfbuzz/ \-DHARFBUZZ_INCLUDE_DIRS=/media/hello/data/3rd_party_lib/harfbuzz/9.0.0/arm64-v8a/include/harfbuzz \-DHARFBUZZ_LIBRARIES=/media/hello/data/3rd_party_lib/harfbuzz/9.0.0/arm64-v8a/lib/libharfbuzz.so \-DWITH_FREETYPE=ON \-DBUILD_opencv_freetype=ON \-DCMAKE_BUILD_TYPE=Release \-DBUILD_SHARED_LIBS=ON \-DWITH_ARUCO=OFF \-DBUILD_opencv_barcode=OFF \-DBUILD_opencv_bgsegm=OFF \-DBUILD_opencv_datasets=OFF \-DBUILD_opencv_python2=OFF \-DBUILD_opencv_python3=OFF \-DBUILD_TESTS=OFF \-DCMAKE_INSTALL_PREFIX=/media/hello/data/3rd_party_lib/opencv/4.6.0/arm64-v8a \-DCMAKE_CXX_FLAGS="-frtti -Os" \-DCMAKE_C_FLAGS="-Os"make -j$(nproc)make install

在libopencv_videoio.so中会包含

hello@hello:/media/hello/data/3rd_party/opencv4.6.0/opencv-4.6.0$ objdump -x /media/hello/data/3rd_party_lib/opencv/4.6.0/arm64-v8a-src/sdk/native/libs/arm64-v8a/libopencv_videoio.s
o |grep NEEDEDNEEDED               libopencv_imgcodecs.soNEEDED               libdl.soNEEDED               liblog.soNEEDED               libopencv_imgproc.soNEEDED               libopencv_core.soNEEDED               libandroid.soNEEDED               libmediandk.soNEEDED               libcamera2ndk.soNEEDED               libc++_shared.soNEEDED               libc.so

对于简单的应用不需要和android互操作的，想要去除libandroid.so libmediandk.so的依赖：
在modules/videoio/cmake/init.cmake中注释掉下面这两个

# add_backend("android_mediandk" WITH_ANDROID_MEDIANDK)
# add_backend("android_camera" WITH_ANDROID_NATIVE_CAMERA)

去除后

hello@hello:/media/hello/data/3rd_party/opencv4.6.0/opencv-4.6.0$ objdump -x /media/hello/data/3rd_party_lib/opencv/4.6.0/arm64-v8a/sdk/native/libs/arm64-v8a/libopencv_videoio.so |grep NEEDEDNEEDED               libopencv_imgcodecs.soNEEDED               libdl.soNEEDED               libopencv_core.soNEEDED               libc++_shared.soNEEDED               libc.so