无法为Android构建opencv

Question

我需要使用其contrib模块为android构建opencv，我试图像本教程对dlib（https://medium.com/beesightsoft/build-dlib-c-for-android-5593589bcc21）所做的那样，并且还基于以下来自github（https://github.com/opencv/opencv/issues/8742 ）：

我在Ubuntu 18上使用以下代码：

export ANDROID_HOME=$HOME/Android/Sdk
export ANDROID_NDK_HOME=$ANDROID_HOME/ndk-bundle
cmake -GNinja \
-DINSTALL_ANDROID_EXAMPLES=ON \
-DANDROID_EXAMPLES_WITH_LIBS=ON \
-DANDROID_ABI=armeabi-v7a \
-DANDROID_SDK=../Android/Sdk \
-DANDROID_SDK_BUILD_TOOLS_VERSION=29 \
-DANDROID_NATIVE_API_LEVEL=27 \
-DBUILD_EXAMPLES=ON \
-DBUILD_DOCS=OFF \
-DCMAKE_MAKE_PROGRAM=/home/user/Android/Sdk/cmake/3.10.2.4988404/bin//ninja \
-DWITH_OPENCL=OFF \
-DWITH_IPP=ON \
-DCMAKE_TOOLCHAIN_FILE=${ANDROID_NDK_HOME}/build/cmake/android.toolchain.cmake \
-DANDROID_TOOLCHAIN=clang \
-DANDROID_STL="c++_static" \
-DANDROID_SDK_TARGET=27 \
-DOPENCV_ENABLE_NONFREE=ON \
-DOPENCV_EXTRA_MODULES_PATH=../opencv_contrib-4.0.1/modules 
../opencv-4.0.1
ninja
ninja install

它与dlib所使用的代码相似，但是在忍者和忍者安装中出现以下错误：

Building OpenCV Android library project
FAILED: opencv_android/opencv/build/outputs/aar/opencv-release.aar CMakeFiles/dephelper/opencv_java_android 
cd /home/user/android_build/opencv_android && ./gradlew -i opencv:assemble && /usr/bin/cmake -E touch /home/user/android_build/CMakeFiles/dephelper/opencv_java_android

FAILURE: Build failed with an exception.

* What went wrong:
Could not determine java version from '11.0.3'.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org
[3/360] Building CXX object samples/cp...mple_cpp_watershed.dir/watershed.cpp.o
ninja: build stopped: subcommand failed.

我已经用以下方法更新了gradle：

sudo add-apt-repository ppa:cwchien/gradle
sudo apt-get update
sudo apt upgrade gradle

有人知道发生了什么事吗？