UPDATE 21-Oct-19: Deprecated Git/Simpler Way in favor of new AndroidOpenCVGradlePlugin
UPDATE 22-May-18: Added missing step number 6.
UPDATE 10-May-17: New solution provides proper integration of OpenCV into application with CMake and Android Gradle plugin 2.3.1. Tested using Android Studio 2.3.1.
UPDATE 11-May-17: An additional solution has been provided
There are two ways of including OpenCV.
Using AndroidOpenCVGradlePlugin
Visit https://github.com/ahasbini/AndroidOpenCVGradlePlugin for more details.
Git/Simpler Way
Visit https://github.com/ahasbini/Android-OpenCV for more details.
Manual/Advanced Way
To include OpenCV libraries into Android Studio Project, its best to create a new Library Module in the project and port the files from OpenCV Android SDK bundle into it:
- Create a new module by selecting File>New Module.
- Select "Android Library", and then enter the details:
- Library name:
OpenCV
- Module name:
opencv
- Package name:
org.opencv
- Once the new module created, copy the contents of
path_to_opencv_sdk/sdk/java/src directory into path_to_your_project/opencv/src/main/java.
- Under
main, create the following directly path: aidl/org/opencv/engine and move main/java/org/opencv/engine/OpenCVEngineInterface.aidl into it.
- Copy the contents of
path_to_opencv_sdk/sdk/java/res into path_to_your_project/opencv/src/main/res.
- Create
sdk folder inside path_to_your_project/opencv/src/ and copy path_to_opencv_sdk/sdk/native folder into it.
- Within the
opencv module, create CMakeLists.txt file and add the following lines in the following order:
cmake_minimum_required(VERSION 3.4.1)
set(OpenCV_DIR "src/sdk/native/jni")
find_package(OpenCV REQUIRED)
message(STATUS "OpenCV libraries: ${OpenCV_LIBS}")
include_directories(${OpenCV_INCLUDE_DIRS})
- Within the
opencv module, edit the build.gradle file as such:
...
android {
...
defaultConfig {
minSdkVersion 8
targetSdkVersion 25
versionCode 3200
versionName "3.2.0"
...
externalNativeBuild {
cmake {
cppFlags "-frtti -fexceptions"
}
}
}
buildTypes {
...
}
externalNativeBuild {
cmake {
path "CMakeLists.txt"
}
}
sourceSets {
main {
jni.srcDirs = [jni.srcDirs, 'src/sdk/native/jni/include']
jniLibs.srcDirs = [jniLibs.srcDirs, 'src/sdk/native/3rdparty/libs', 'src/sdk/native/libs']
}
}
}
...
- Within the
app (application module, could be another name) module, create/edit CMakeLists.txt file and add the following lines in the following order (Note the different path set to OpenCV_DIR):
set(OpenCV_DIR "../opencv/src/sdk/native/jni")
find_package(OpenCV REQUIRED)
message(STATUS "OpenCV libraries: ${OpenCV_LIBS}")
target_link_libraries(YOUR_TARGET_LIB ${OpenCV_LIBS})
- Within the
app (application module, could be another name) module, edit the build.gradle file as such:
...
android {
...
defaultConfig {
...
externalNativeBuild {
cmake {
cppFlags "-frtti -fexceptions"
}
}
buildTypes {
...
}
externalNativeBuild {
cmake {
path "CMakeLists.txt"
}
}
}
dependencies {
...
compile project(':opencv')
}
- Do a gradle sync, and now the OpenCV native libs, header files and Java wrapper classes are included.
When project is built and apk is launched, you could inspect the packaged apk under path_to_project/path_to_app_module/build/output/ (drag the apk onto the text editor tabs of Android Studio)
You should see a libopencv_java3.so under each abi architecture folder.
Initialize the OpenCV SDK in your java class :
public class MyClass {
static {
if (BuildConfig.DEBUG) {
OpenCVLoader.initDebug();
}
}
...
}
And you should see within logcat messages specifying the OpenCV has been loaded (the first error is normal):
05-10 10:42:31.451 D/OpenCV/StaticHelper: Trying to get library list
05-10 10:42:31.452 E/OpenCV/StaticHelper: OpenCV error: Cannot load info library for OpenCV
05-10 10:42:31.452 D/OpenCV/StaticHelper: Library list: ""
05-10 10:42:31.452 D/OpenCV/StaticHelper: First attempt to load libs
05-10 10:42:31.452 D/OpenCV/StaticHelper: Trying to init OpenCV libs
05-10 10:42:31.452 D/OpenCV/StaticHelper: Trying to load library opencv_java3
05-10 10:42:32.031 D/OpenCV/StaticHelper: Library opencv_java3 loaded
05-10 10:42:32.031 D/OpenCV/StaticHelper: First attempt to load libs is OK
05-10 10:42:32.045 I/OpenCV/StaticHelper: General configuration for OpenCV 3.2.0 =====================================
05-10 10:42:32.045 I/OpenCV/StaticHelper: Version control: 3.2.0
05-10 10:42:32.045 I/OpenCV/StaticHelper: Platform:
05-10 10:42:32.045 I/OpenCV/StaticHelper: Timestamp: 2016-12-23T13:04:49Z
05-10 10:42:32.045 I/OpenCV/StaticHelper: Host: Linux 4.8.0-25-generic x86_64
05-10 10:42:32.045 I/OpenCV/StaticHelper: Target: Linux 1 x86_64
05-10 10:42:32.045 I/OpenCV/StaticHelper: CMake: 2.8.12.2
05-10 10:42:32.045 I/OpenCV/StaticHelper: CMake generator: Ninja
05-10 10:42:32.045 I/OpenCV/StaticHelper: CMake build tool: /usr/bin/ninja
05-10 10:42:32.045 I/OpenCV/StaticHelper: Configuration: Release
05-10 10:42:32.045 I/OpenCV/StaticHelper: C/C++:
05-10 10:42:32.045 I/OpenCV/StaticHelper: Built as dynamic libs?: NO
05-10 10:42:32.045 I/OpenCV/StaticHelper: C++ Compiler: /usr/bin/ccache /opt/android/android-ndk-r10e/toolchains/x86_64-4.9/prebuilt/linux-x86_64/bin/x86_64-linux-android-g++ (ver 4.9)
