How to import OpenCV 4.5.2 in android studio

Step 1: Download OpenCV SDK

Download from https://opencv.org/releases/ and unzip it.

Step 2: Create your android project with JNI

File > New > New Project…

Step 3: Import OpenCV

File > New > Import Module…

And choose the “sdk” folder in the OpenCV SDK.

Some tutorials suggested to rename the folder before import. Don’t do that. It is because OpenCV hardcoded the path with the name of “sdk” in the native/jni/OpenCVConfig.cmake

Step 4: Edit setting.gradle

1. Open setting.gradle
2. Add a module with the name “opencv” and link to the folder “sdk”

include "opencv"
project(":opencv").projectDir = file("sdk")

Step 5: Edit the application build.gradle

1. Open the application build.gradle which is under the “app” folder.
2. Add OpenCV_DIR cmake argument under
   android > defaultConfig > externalNativeBuild > cmake

arguments "-DOpenCV_DIR=" + file('../sdk').absolutePath + "/native/jni",
        "-DANDROID_TOOLCHAIN=clang",
        "-DANDROID_STL=c++_shared"

3. Add OpenCV module dependency to application

implementation project(':opencv')

Step 6: Modify the application cmake file

1. Open CMakeLists.txt in app/src/main/cpp
2. Add the following code to load the OpenCV package

set(ANDROID_OPENCV_COMPONENTS "opencv_java" CACHE STRING "")
message(STATUS "ANDROID_ABI=${ANDROID_ABI}")
find_package(OpenCV REQUIRED COMPONENTS ${ANDROID_OPENCV_COMPONENTS})

3. Link project with the library

target_link_libraries(${PROJECT_NAME} ${ANDROID_OPENCV_COMPONENTS})

Final: Sync Gradle

And now you can import OpenCV library in JNI

and in the java.

To study how to program OpenCV, read samples in the SDK folder you have downloaded. Enjoy~