Reputation: 239
How can I merge two Android.mk files when adding a library?
I'm new with Android so I don't fully understand how to make Android.mk files. My project was running fine, following a tutorial online where the Android.mk was provided. But later on I needed to add a missing library and the tutorial for that had another Android.mk, now I'm trying to merge the two together.
Here is my Android.mk :
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
#opencv
OPENCVROOT:= C:\OpenCV-2.4.10-android-sdk
OPENCV_CAMERA_MODULES:=on
OPENCV_INSTALL_MODULES:=on
OPENCV_LIB_TYPE:=SHARED
include ${OPENCVROOT}/sdk/native/jni/OpenCV.mk
LOCAL_SRC_FILES := com_example_adrien_ndkopencvtest4_OpencvNativeClass.cpp
LOCAL_LDLIBS += -llog
LOCAL_MODULE := MyOpencvLibs
include $(BUILD_SHARED_LIBRARY)
Here is the Android.mk I need to add :
LOCAL_PATH := $(call my-dir)
OPENCV_PATH := D:/CODE/OpenCV-2.4.10-android-sdk/sdk/native/jni
include $(CLEAR_VARS)
LOCAL_MODULE := nonfree
LOCAL_SRC_FILES := libnonfree.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
OPENCV_INSTALL_MODULES := on
OPENCV_CAMERA_MODULES := off
include $(OPENCV_PATH)/OpenCV.mk
LOCAL_C_INCLUDES := \
$(LOCAL_PATH) \
$(OPENCV_PATH)/include
LOCAL_SRC_FILES := \
nonfree_jni.cpp
LOCAL_MODULE := nonfree_demo
LOCAL_CFLAGS := -Werror -O3 -ffast-math
LOCAL_LDLIBS := -llog -ldl
LOCAL_SHARED_LIBRARIES += nonfree
include $(BUILD_SHARED_LIBRARY)
What I'm interested in in the last Android.mk is the libnonfree.so only, I don't need the cpp file.
Here is the structure of my project :
EDIT :
Thanks for your answers. I've done what was suggested and my Android.mk looks like that now :
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
#opencv
OPENCVROOT:= C:\OpenCV-2.4.10-android-sdk
OPENCV_CAMERA_MODULES:=on
OPENCV_INSTALL_MODULES:=on
OPENCV_LIB_TYPE:=SHARED
include ${OPENCVROOT}/sdk/native/jni/OpenCV.mk
LOCAL_SRC_FILES := com_example_adrien_ndkopencvtest4_OpencvNativeClass.cpp
LOCAL_LDLIBS += -llog
LOCAL_SHARED_LIBRARIES += nonfree
LOCAL_MODULE := MyOpencvLibs
include $(BUILD_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := nonfree
LOCAL_SRC_FILES := libnonfree.so
include $(PREBUILT_SHARED_LIBRARY)
But the problem remains. I've got "Undefined reference" to methods libnonfree.so should add. I assumed the problem was from the Android.mk but maybe it's from elsewhere then.
I've added System.loadLibrary("nonfree"); to my MainACtivity and
#include "opencv2/nonfree/nonfree.hpp"
#include "opencv2/nonfree/features2d.hpp"
I don't know what I'm doing wrong.
EDIT 2 :
Here is the error :
Application.mk :
APP_STL := gnustl_static
APP_CPPFLAGS := -frtti -fexceptions
APP_ABI := armeabi-v7a
APP_PLATFORM := android-16
I didn't know where to set arguments="V=1" in my build.gradle
My build.gradle :
apply plugin: 'com.android.application'
android {
compileSdkVersion 25
buildToolsVersion "25.0.2"
defaultConfig {
applicationId "com.example.adrien.ndkopencvtest4"
minSdkVersion 15
targetSdkVersion 25
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
sourceSets.main {
//jniLibs.srcDirs = ['src/main/jniLibs']
jni.srcDirs = [] //disable automatic ndk-build call
}
task ndkBuild(type: Exec, description: 'Compile JNI source via NDK') {
commandLine "C:/Users/Adrien/AppData/Local/Android/sdk/ndk-bundle/ndk-build.cmd",
'NDK_PROJECT_PATH=build/intermediates/ndk',
'NDK_LIBS_OUT=src/main/jniLibs',
'APP_BUILD_SCRIPT=src/main/jni/Android.mk',
'NDK_APPLICATION_MK=src/main/jni/Application.mk'
}
tasks.withType(JavaCompile) {
compileTask -> compileTask.dependsOn ndkBuild
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(include: ['*.jar'], dir: 'libs')
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
exclude group: 'com.android.support', module: 'support-annotations'
})
compile 'com.github.wseemann:FFmpegMediaMetadataRetriever-armeabi-v7a:1.0.14'
compile 'com.android.support:appcompat-v7:25.3.1'
compile 'com.android.support.constraint:constraint-layout:1.0.2'
testCompile 'junit:junit:4.12'
compile project(':openCVLibrary2410')
}
EDIT 3 :
Results of "ndk-build V=1" :
C:\Users\Adrien\AndroidStudioProjects\NDKOpencvTest4\app\src\main\jni>ndk-build V=1
[armeabi-v7a] SharedLibrary : libMyOpencvLibs.so
C:/Users/Adrien/AppData/Local/Android/sdk/ndk-bundle/build//../toolchains/llvm/preb
uilt/windows-x86_64/bin/clang++.exe -Wl,-soname,libMyOpencvLibs.so -shared --sysroo
t=C:/Users/Adrien/AppData/Local/Android/sdk/ndk-bundle/build//../platforms/android-
16/arch-arm C:/Users/Adrien/AndroidStudioProjects/NDKOpencvTest4/app/src/main/obj/l
ocal/armeabi-v7a/objs/MyOpencvLibs/com_example_adrien_ndkopencvtest4_OpencvNativeCl
ass.o C:/Users/Adrien/AppData/Local/Android/sdk/ndk-bundle/build//../sources/cxx-st
l/gnu-libstdc++/4.9/libs/armeabi-v7a/libgnustl_static.a -lgcc C:/Users/Adrien/Andro
idStudioProjects/NDKOpencvTest4/app/src/main/obj/local/armeabi-v7a/libopencv_java.s
o C:/Users/Adrien/AndroidStudioProjects/NDKOpencvTest4/app/src/main/obj/local/armea
bi-v7a/libnonfree.so -gcc-toolchain C:/Users/Adrien/AppData/Local/Android/sdk/ndk-
bundle/build//../toolchains/arm-linux-androideabi-4.9/prebuilt/windows-x86_64 -no-c
anonical-prefixes -target armv7-none-linux-androideabi -Wl,--fix-cortex-a8 -Wl,--b
uild-id -Wl,--no-undefined -Wl,-z,noexecstack -Wl,-z,relro -Wl,-z,now -Wl,--warn-sh
ared-textrel -Wl,--fatal-warnings -LC:/Users/Adrien/AppData/Local/Android/sdk/ndk
-bundle/build//../platforms/android-16/arch-arm/usr/lib -llog -lc -lm -o C:/Users/A
drien/AndroidStudioProjects/NDKOpencvTest4/app/src/main/obj/local/armeabi-v7a/libMy
OpencvLibs.so
C:/Users/Adrien/AndroidStudioProjects/NDKOpencvTest4/app/src/main/jni/com_example_a
drien_ndkopencvtest4_OpencvNativeClass.cpp:214: error: undefined reference to 'cv::
SURF::SURF(double, int, int, bool, bool)'
C:/Users/Adrien/AndroidStudioProjects/NDKOpencvTest4/app/src/main/jni/com_example_a
drien_ndkopencvtest4_OpencvNativeClass.cpp:222: error: undefined reference to 'cv::
SURF::SURF()'
C:/Users/Adrien/AndroidStudioProjects/NDKOpencvTest4/app/src/main/jni/com_example_a
drien_ndkopencvtest4_OpencvNativeClass.cpp:204: error: undefined reference to 'VTT
for cv::SURF'
C:/Users/Adrien/AndroidStudioProjects/NDKOpencvTest4/app/src/main/jni/com_example_a
drien_ndkopencvtest4_OpencvNativeClass.cpp:204: error: undefined reference to 'VTT
for cv::SURF'
C:/Users/Adrien/AndroidStudioProjects/NDKOpencvTest4/app/src/main/jni/com_example_a
C:/Users/Adrien/AndroidStudioProjects/NDKOpencvTest4/app/src/main/jni/com_example_adrien_ndkopencvtest4_OpencvNativeClass.cpp:204: error: undefined
reference to 'VTT for cv::SURF'
C:/Users/Adrien/AndroidStudioProjects/NDKOpencvTest4/app/src/main/jni/com_example_adrien_ndkopencvtest4_OpencvNativeClass.cpp:449: error: undefined
reference to 'cv::SURF::SURF(double, int, int, bool, bool)'
C:/Users/Adrien/AndroidStudioProjects/NDKOpencvTest4/app/src/main/jni/com_example_adrien_ndkopencvtest4_OpencvNativeClass.cpp:457: error: undefined
reference to 'cv::SURF::SURF()'
clang++.exe: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [C:/Users/Adrien/AndroidStudioProjects/NDKOpencvTest4/app/src/main/obj/local/armeabi-v7a/libMyOpencvLibs.so] Error 1
SOLUTION :
My libnonfree.so file was not correct, I downloaded another one. I also changed my Application.mk file to :
APP_STL := gnustl_static
APP_CPPFLAGS := -frtti -fexceptions
APP_ABI := armeabi-v7a
APP_PLATFORM := android-16
Upvotes: 1
Views: 1823
Answers (2)
Reputation: 568
Modify your android.mk as:
LOCAL_PATH := $(call my-dir)
OPENCV_PATH := D:/CODE/OpenCV-2.4.10-android-sdk/sdk/native/jni
include $(CLEAR_VARS)
LOCAL_MODULE := nonfree
LOCAL_SRC_FILES := libnonfree.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
#opencv
OPENCVROOT:= C:\OpenCV-2.4.10-android-sdk
OPENCV_CAMERA_MODULES:=on
OPENCV_INSTALL_MODULES:=on
OPENCV_LIB_TYPE:=SHARED
include ${OPENCVROOT}/sdk/native/jni/OpenCV.mk
LOCAL_SRC_FILES := com_example_adrien_ndkopencvtest4_OpencvNativeClass.cpp
LOCAL_SHARED_LIBRARIES += nonfree
LOCAL_LDLIBS += -llog
LOCAL_MODULE := MyOpencvLibs
include $(BUILD_SHARED_LIBRARY)
Here the prebuild library i.e. libnonfree.so is declared in the android.mk, and referenced to it later via
LOCAL_SHARED_LIBRARIES += nonfree
Now to use it you need to load the latest built library in yout MainActivity i.e.
System.loadLibrary("MyOpencvLibs");
Thats it, now you have merged both the android.mk files into a new module named: MyOpencvLibs
For better understanding you can read my blog : https://androidtutsweb.wordpress.com/2017/04/04/android-mk-for-ndk-build-using-pre-build-libraries/
Upvotes: 0
Reputation: 57163
If you want to add a prebuilt shared library to your project, you don't need a separate Android.mk
Let's take your script,
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
#opencv
OPENCVROOT:= C:\OpenCV-2.4.10-android-sdk
OPENCV_CAMERA_MODULES:=on
OPENCV_INSTALL_MODULES:=on
OPENCV_LIB_TYPE:=SHARED
include ${OPENCVROOT}/sdk/native/jni/OpenCV.mk
LOCAL_SRC_FILES := com_example_adrien_ndkopencvtest4_OpencvNativeClass.cpp
LOCAL_LDLIBS += -llog
LOCAL_MODULE := MyOpencvLibs
include $(BUILD_SHARED_LIBRARY)
and simply add to the bottom the extra module you need:
include $(CLEAR_VARS)
LOCAL_MODULE := nonfree
LOCAL_SRC_FILES := libnonfree.so
include $(PREBUILT_SHARED_LIBRARY)
Now the file C:\Users\Adrien\AndroidStudioProjects\NDKOpencvTest4\app\src\main\jni\libnonfree.so will be packed into your APK.
If you need this library to link your libMyOpencvLibs.so (this means, if your code in com_example_adrien_ndkopencvtest4_OpencvNativeClass.cpp uses some functions exported from libnonfree.so, you should also refeence it in your module:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
#opencv
OPENCVROOT:= C:\OpenCV-2.4.10-android-sdk
OPENCV_CAMERA_MODULES:=on
OPENCV_INSTALL_MODULES:=on
OPENCV_LIB_TYPE:=SHARED
include ${OPENCVROOT}/sdk/native/jni/OpenCV.mk
LOCAL_SRC_FILES := com_example_adrien_ndkopencvtest4_OpencvNativeClass.cpp
LOCAL_LDLIBS += -llog
LOCAL_SHARED_LIBRARIES += nonfree
LOCAL_MODULE := MyOpencvLibs
include $(BUILD_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := nonfree
LOCAL_SRC_FILES := libnonfree.so
include $(PREBUILT_SHARED_LIBRARY)
Upvotes: 1
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