ci/build.py build MXNet for Android_armv7

[bykim555]

OS: Ubuntu 18.04 64bit LTS
Anaconda3-2019.03-Linux-x86_64
conda env used, Python: 3.6.8

pip install docker, pip install docker-compose
git clone --recursive https://github.com/apache/incubator-mxnet.git
cd incubator-mxnet
git checkout 1.5.1
git submodule update --init --recursive
ci/build.py -p android_armv7 ( ndk17, api 24)

Tried to build Android_armv7 using ci/build.py and sucess.

Use Android Studio.

Android.mk,
include $(CLEAR_VARS)
LOCAL_MODULE := mxnet_inference
LOCAL_SRC_FILES := $(LOCAL_PATH)/libs/libmxnet.so
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include/mxnet
include $(PREBUILT_SHARED_LIBRARY)
...
LOCAL_SHARED_LIBRARIES += mxnet_inference
include $(BUILD_SHARED_LIBRARY)
Application.mk
APP_ABI := armeabi-v7a
APP_PLATFORM := android-24
APP_STL := c++_static
NDK_TOOLCHAIN_VERSION := clang
APP_BUILD_SCRIPT := Android.mk

build.gradle
android {
compileSdkVersion 29
buildToolsVersion "29.0.2"
defaultConfig {
applicationId "com.tistory.webnautes.useopencvwithndk_build"
minSdkVersion 21
targetSdkVersion 25
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"

// ndk {
// abiFilters "armeabi-v7a"
// }
}

buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
externalNativeBuild {
ndkBuild {
path 'src/main/jni/Android.mk'
}
}

packagingOptions {
// pickFirst 'lib/arm64-v8a/'
pickFirst 'lib/armeabi-v7a/'
// pickFirst 'lib/x86/'
// pickFirst 'lib/x86_64/'
}
}

error showed as follows:
#==================
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.tistory.webnautes.useopencvwithndk_build, PID: 12657
java.lang.UnsatisfiedLinkError: dlopen failed: cannot locate symbol "__aeabi_memcpy4" referenced by "/data/app/com.tistory.webnautes.useopencvwithndk_build-2/lib/arm/libmxnet.so"...
at java.lang.Runtime.loadLibrary(Runtime.java:372)
at java.lang.System.loadLibrary(System.java:1076)
at com.tistory.webnautes.useopencvwithndk_build.MainActivity.(MainActivity.java:48)
at java.lang.Class.newInstance(Native Method)
at android.app.Instrumentation.newActivity(Instrumentation.java:1095)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3083)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3349)
at android.app.ActivityThread.access$1100(ActivityThread.java:221)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7224)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
I/Process: Sending signal. PID: 12657 SIG: 9
#=======================================
How to fix that? Thank you.

[leezu]

Please try MXNet 1.8 or master branch

[bykim555]

Tried to build version mxnet1.8.0.rc2, Android_armv7 using ci/build.py and sucess.
But ./cpp-package/include/mxnet-cpp/op.h not found.
This file include MxNetCpp.h...