ndk-build returns non-zero value 2 (checked all the other stack questions already!)

Question

I know there is several questions with the same title but after working my way through every single one I could find for hours, I decided to post a new question.

my Android.mk looks like

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_SRC_FILES := com_lunaticcoding_colosseum_OpenCv.cpp

LOCAL_LDLIBS += -llog
LOCAL_MODULE := OpenCvFace


include $(BUILD_SHARED_LIBRARY)

my Application.mk

APP_OPTIM := release
APP_PLATFORM := android-21
APP_STL := gnustl_static
APP_CPPFLAGS += -frtti
APP_CPPFLAGS += -fexceptions
APP_CPPFLAGS += -DANDROID
APP_ABI := armeabi-v7a

my .h file

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
#include "opencv2/opencv.hpp"
/* Header for class com_lunaticcoding_colosseum_OpenCv */

#ifndef _Included_com_lunaticcoding_colosseum_OpenCv
#define _Included_com_lunaticcoding_colosseum_OpenCv
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     com_lunaticcoding_colosseum_OpenCv
 * Method:    faceDetection
 * Signature: (J)V
 */
 void detect(Mat& frame);

 JNIEXPORT void JNICALL Java_com_lunaticcoding_colosseum_OpenCv_faceDetection
 (JNIEnv *, jclass, jlong);

#ifdef __cplusplus
}
#endif
#endif

my .cpp file

#include <jni.h>
#include "com_lunaticcoding_colosseum_OpenCv.h"

JNIEXPORT void JNICALL Java_com_lunaticcoding_colosseum_OpenCv_faceDetection
  (JNIEnv *, jclass, jlong addrRgba){
    //Mat& frame = *(Mat *) addrRgba;

    //detect(frame);
}

void detect(Mat& frame) {

}

I added android.useDepricatedNdk=true to the properties file and my "error message" looks like:

EDIT (removed the error message because obsolete and makes question more difficult to read) (Reg. Adding OpenCV to Native C code through CMake on Android Studio) I feel like I am really close :O but no clue what I am missing now

#include <jni.h>
#include <string>
#include <opencv>

extern "C" JNIEXPORT jstring

JNICALL
Java_com_lunaticcoding_opencvtest_MainActivity_getFace(
        JNIEnv *env,
        jobject /* this */) {
    std::string hello = "Hello from test";
    return env->NewStringUTF(hello.c_str());
}

following error

Build command failed. Error while executing process /Users/lunaticcoding/Library/Android/sdk/cmake/3.6.4111459/bin/cmake with arguments {--build /Users/lunaticcoding/AndroidStudioProjects/OpenCvTest2/app/.externalNativeBuild/cmake/debug/x86_64 --target OpenCvFace} [1/2] Building CXX object CMakeFiles/OpenCvFace.dir/src/main/cpp/OpenCvFace.cpp.o FAILED: /Users/lunaticcoding/Library/Android/sdk/ndk-bundle/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang++ --target=x86_64-none-linux-android --gcc-toolchain=/Users/lunaticcoding/Library/Android/sdk/ndk-bundle/toolchains/x86_64-4.9/prebuilt/darwin-x86_64 --sysroot=/Users/lunaticcoding/Library/Android/sdk/ndk-bundle/sysroot -DOpenCvFace_EXPORTS -isystem /Users/lunaticcoding/Documents/OpenCV-android-sdk/sdk/native/jni/include -isystem /Users/lunaticcoding/Documents/OpenCV-android-sdk/sdk/native/jni/include/opencv -isystem /Users/lunaticcoding/Library/Android/sdk/ndk-bundle/sources/cxx-stl/gnu-libstdc++/4.9/include -isystem /Users/lunaticcoding/Library/Android/sdk/ndk-bundle/sources/cxx-stl/gnu-libstdc++/4.9/libs/x86_64/include -isystem /Users/lunaticcoding/Library/Android/sdk/ndk-bundle/sources/cxx-stl/gnu-libstdc++/4.9/include/backward -isystem /Users/lunaticcoding/Library/Android/sdk/ndk-bundle/sysroot/usr/include/x86_64-linux-android -D__ANDROID_API__=21 -g -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -Wa,--noexecstack -Wformat -Werror=format-security -frtti -fexceptions -O0 -fno-limit-debug-info -fPIC -MD -MT CMakeFiles/OpenCvFace.dir/src/main/cpp/OpenCvFace.cpp.o -MF CMakeFiles/OpenCvFace.dir/src/main/cpp/OpenCvFace.cpp.o.d -o CMakeFiles/OpenCvFace.dir/src/main/cpp/OpenCvFace.cpp.o -c /Users/lunaticcoding/AndroidStudioProjects/OpenCvTest2/app/src/main/cpp/OpenCvFace.cpp /Users/lunaticcoding/AndroidStudioProjects/OpenCvTest2/app/src/main/cpp/OpenCvFace.cpp:3:10: fatal error: 'opencv' file not found include ^~~~~~~~ 1 error generated. ninja: build stopped: subcommand failed.

Answer 1

Make sure that you have up-to-date Android Studio. Remove android.useDepricatedNdk=true and use externalNativeBuild as described in the official NDK tutorial.

I see that you need OpenCv to build and run your code. Please follow their instructions to have all needed headers and libraries referenced correctly in your Android.mk.

Please remember that Android Studio ignores APP_ABI defined in Application.mk. Instead, you should define abiFilters in your build.gradle.