How to integrate OpenCV with Android Studio
This article is about how Android Studio integrates OpenCV. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.
My environment:
Android Studio Arctic Fox + JDK11 + Gradle 7.0.2 + NDK21 + opencv-4.5.1-android-sdk
Code link:
Build Demo in OpenCV environment
1. Create a Native project
two。 Download OpenCV SDK
OpenCV SDK
3. Create a new libs folder under the cpp directory of Android Studio
Copy the whole OpenCV SDK under the folder "OpenCV-android-sdk\ sdk\ native\ libs" we downloaded to the libs folder just now.
4. Copy the entire include folder under the "OpenCV-android-sdk\ sdk\ native\ jni" path to the cpp folder.
5. Configure build.gradle
6. Configure CMakelists.txt
# the purpose is to let CMake find out where our header file is. Here is include_directories (include) # set the system variable under the cpp/include folder. The goal is to let CMake know where to find our libopencv_java4.so library set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}-L ${CMAKE_SOURCE_DIR} / libs/$ {ANDROID_ABI}") target_link_libraries (myopencv opencv_java4 # link libopencv_java4.so, so that this so ${log-lib} will be found in the generated APK)
7. Click build and find the library we introduced in the generated apk
The next thing is that the runtime will report an error.
Java.lang.UnsatisfiedLinkError: dlopen failed: library "libc++_shared.so" not found
The reason is that before NDK18 was compiled by gcc, NDK18 was later compiled by clang, and NDK18 no longer has the library libc++_shared.so, so an error will be reported at run time.
Solution:
Add a sentence to build.gradle
Arguments'- DANDROID_STL=c++_shared'
In this way, the library libc++_shared.so can be obtained remotely
After recompiling, we found that there is libc++_shared.so in apk, and apk can run normally.
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