[英]Building OpenCV for Android and using it with the NDK
背景:我目前正在Android Studio上為Moverio BT 200增強現實眼鏡開發應用程序。 我正在使用OpenCV,特別是庫的arUco模塊。 該模塊必須與NDK一起使用。 此外,它不在穩定版本上,所以我自己編譯了庫(使用本指南: https : //zami0xzami.wordpress.com/2016/03/17/building-opencv-for-android-from-source/ ) 。 圖書館的建設進展順利。 之后,我做了一個android studio項目(customOCVtest)。 我在使用OpenCV與Android Studio和NDK時總是這樣做,除了這次使用自定義構建。 我檢查了庫是否正確加載:
private static final String OCVdevTAG = "OCVmainAct";
static {
System.loadLibrary("native-lib");
if(!OpenCVLoader.initDebug()) {
Log.d(OCVdevTAG, "OpenCV not loaded");
} else {
Log.d(OCVdevTAG, "OpenCV loaded");
}
}
我構建時確實加載了庫。
現在出現了問題:當我嘗試在我的本機代碼中實際使用arUco模塊時(這是我的native-lib.cpp):
#include <jni.h>
#include <string>
#include <opencv2/aruco.hpp>
extern "C" {
jstring
Java_com_jambonsama_customocvtest_MainActivity_stringFromJNI(
JNIEnv *env,
jobject /* this */) {
std::string hello = "Hello from C++";
cv::Ptr<cv::aruco::Dictionary> dict = cv::aruco::getPredefinedDictionary(cv::aruco::DICT_6X6_250);
cv::Mat marker;
cv::aruco::drawMarker(dict, 25, 200, marker, 1);
return env->NewStringUTF(hello.c_str());
}
}
gradle sync工作,但我無法構建。 我收到以下錯誤:
Error:FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':app:externalNativeBuildDebug'.
> Build command failed.
Error while executing 'C:\Users\JambonSama\AppData\Local\Android\Sdk\cmake\3.6.3155560\bin\cmake.exe' with arguments {--build C:\Users\JambonSama\AndroidStudioProjects\customOCVtest\app\.externalNativeBuild\cmake\debug\mips64 --target native-lib}
[1/1] Linking CXX shared library ..\..\..\..\build\intermediates\cmake\debug\obj\mips64\libnative-lib.so
FAILED: cmd.exe /C "cd . && C:\Users\JambonSama\AppData\Local\Android\sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\clang++.exe -target mips64el-none-linux-android -gcc-toolchain C:/Users/JambonSama/AppData/Local/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/windows-x86_64 --sysroot=C:/Users/JambonSama/AppData/Local/Android/sdk/ndk-bundle/platforms/android-21/arch-mips64 -fPIC -g -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -Wa,--noexecstack -Wformat -Werror=format-security -fno-exceptions -fno-rtti -g -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -Wa,--noexecstack -Wformat -Werror=format-security -fno-exceptions -fno-rtti -O0 -fno-limit-debug-info -O0 -fno-limit-debug-info -Wl,--build-id -Wl,--warn-shared-textrel -Wl,--fatal-warnings -Wl,--no-undefined -Wl,-z,noexecstack -Qunused-arguments -Wl,-z,relro -Wl,-z,now -Wl,--build-id -Wl,--warn-shared-textrel -Wl,--fatal-warnings -Wl,--no-undefined -Wl,-z,noexecstack -Qunused-arguments -Wl,-z,relro -Wl,-z,now -shared -Wl,-soname,libnative-lib.so -o ..\..\..\..\build\intermediates\cmake\debug\obj\mips64\libnative-lib.so CMakeFiles/native-lib.dir/src/main/cpp/native-lib.cpp.o C:/Libs/opencv_src/opencv/platforms/build_android_arm/install/sdk/native/libs/armeabi-v7a/libopencv_core.a C:/Libs/opencv_src/opencv/platforms/build_android_arm/install/sdk/native/libs/armeabi-v7a/libopencv_aruco.a -llog -lm "C:/Users/JambonSama/AppData/Local/Android/sdk/ndk-bundle/sources/cxx-stl/gnu-libstdc++/4.9/libs/mips64/libgnustl_static.a" && cd ."
C:/Users/JambonSama/AppData/Local/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/windows-x86_64/lib/gcc/mips64el-linux-android/4.9.x/../../../../mips64el-linux-android/bin\ld: C:/Libs/opencv_src/opencv/platforms/build_android_arm/install/sdk/native/libs/armeabi-v7a/libopencv_core.a(alloc.cpp.o): Relocations in generic ELF (EM: 40)
C:/Users/JambonSama/AppData/Local/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/windows-x86_64/lib/gcc/mips64el-linux-android/4.9.x/../../../../mips64el-linux-android/bin\ld: C:/Libs/opencv_src/opencv/platforms/build_android_arm/install/sdk/native/libs/armeabi-v7a/libopencv_core.a(alloc.cpp.o): Relocations in generic ELF (EM: 40)
C:/Users/JambonSama/AppData/Local/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/windows-x86_64/lib/gcc/mips64el-linux-android/4.9.x/../../../../mips64el-linux-android/bin\ld: C:/Libs/opencv_src/opencv/platforms/build_android_arm/install/sdk/native/libs/armeabi-v7a/libopencv_core.a(alloc.cpp.o): Relocations in generic ELF (EM: 40)
C:/Users/JambonSama/AppData/Local/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/windows-x86_64/lib/gcc/mips64el-linux-android/4.9.x/../../../../mips64el-linux-android/bin\ld: C:/Libs/opencv_src/opencv/platforms/build_android_arm/install/sdk/native/libs/armeabi-v7a/libopencv_core.a(alloc.cpp.o): Relocations in generic ELF (EM: 40)
C:/Users/JambonSama/AppData/Local/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/windows-x86_64/lib/gcc/mips64el-linux-android/4.9.x/../../../../mips64el-linux-android/bin\ld: C:/Libs/opencv_src/opencv/platforms/build_android_arm/install/sdk/native/libs/armeabi-v7a/libopencv_core.a(alloc.cpp.o): Relocations in generic ELF (EM: 40)
C:/Users/JambonSama/AppData/Local/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/windows-x86_64/lib/gcc/mips64el-linux-android/4.9.x/../../../../mips64el-linux-android/bin\ld: C:/Libs/opencv_src/opencv/platforms/build_android_arm/install/sdk/native/libs/armeabi-v7a/libopencv_core.a(alloc.cpp.o): Relocations in generic ELF (EM: 40)
C:/Users/JambonSama/AppData/Local/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/windows-x86_64/lib/gcc/mips64el-linux-android/4.9.x/../../../../mips64el-linux-android/bin\ld: C:/Libs/opencv_src/opencv/platforms/build_android_arm/install/sdk/native/libs/armeabi-v7a/libopencv_core.a(alloc.cpp.o): Relocations in generic ELF (EM: 40)
C:/Users/JambonSama/AppData/Local/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/windows-x86_64/lib/gcc/mips64el-linux-android/4.9.x/../../../../mips64el-linux-android/bin\ld: C:/Libs/opencv_src/opencv/platforms/build_android_arm/install/sdk/native/libs/armeabi-v7a/libopencv_core.a(alloc.cpp.o): Relocations in generic ELF (EM: 40)
C:/Users/JambonSama/AppData/Local/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/windows-x86_64/lib/gcc/mips64el-linux-android/4.9.x/../../../../mips64el-linux-android/bin\ld: C:/Libs/opencv_src/opencv/platforms/build_android_arm/install/sdk/native/libs/armeabi-v7a/libopencv_core.a(alloc.cpp.o): Relocations in generic ELF (EM: 40)
C:/Libs/opencv_src/opencv/platforms/build_android_arm/install/sdk/native/libs/armeabi-v7a/libopencv_core.a: error adding symbols: File in wrong format
clang++.exe: error: linker command failed with exit code 1 (use -v to see invocation)
ninja: build stopped: subcommand failed.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
特別是,此錯誤消息告訴我,我嘗試使用以下參數進行構建:
{--build C:\Users\JambonSama\AndroidStudioProjects\customOCVtest\app\.externalNativeBuild\cmake\debug\mips64 --target native-lib}
該參數由AS自動生成,我找不到傳遞它的文件。 我相信,如果我能找到它,我可以為手臂(這是我想要的)而不是mips建造。 問題是,我找不到它。 (而且我甚至不確定那確實是我正在尋找的。我只是想讓我的項目為我的眼鏡而建。)
以下是我的CMakeLists.txt:
# Sets the minimum version of CMake required to build the native
# library. You should either keep the default value or only pass a
# value of 3.4.0 or lower.
cmake_minimum_required(VERSION 3.4.1)
# Creates and names a library, sets it as either STATIC
# or SHARED, and provides the relative paths to its source code.
# You can define multiple libraries, and CMake builds it for you.
# Gradle automatically packages shared libraries with your APK.
add_library( # Sets the name of the library.
native-lib
# Sets the library as a shared library.
SHARED
# Provides a relative path to your source file(s).
# Associated headers in the same location as their source
# file are automatically included.
src/main/cpp/native-lib.cpp )
include_directories(C:/Libs/opencv_src/opencv/platforms/build_android_arm/install/sdk/native/jni/include)
# Searches for a specified prebuilt library and stores the path as a
# variable. Because system libraries are included in the search path by
# default, you only need to specify the name of the public NDK library
# you want to add. CMake verifies that the library exists before
# completing its build.
find_library( # Sets the name of the path variable.
log-lib
# Specifies the name of the NDK library that
# you want CMake to locate.
log )
# Specifies libraries CMake should link to your target library. You
# can link multiple libraries, such as libraries you define in the
# build script, prebuilt third-party libraries, or system libraries.
target_link_libraries( # Specifies the target library.
native-lib
C:/Libs/opencv_src/opencv/platforms/build_android_arm/install/sdk/native/libs/armeabi-v7a/libopencv_core.a
C:/Libs/opencv_src/opencv/platforms/build_android_arm/install/sdk/native/libs/armeabi-v7a/libopencv_aruco.a
# Links the target library to the log library
# included in the NDK.
${log-lib} )
這是我的app build.gradle:
apply plugin: 'com.android.application'
android {
compileSdkVersion 25
buildToolsVersion "25.0.1"
defaultConfig {
applicationId "com.jambonsama.customocvtest"
minSdkVersion 14
targetSdkVersion 25
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
externalNativeBuild {
cmake {
cppFlags ""
}
}
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
externalNativeBuild {
cmake {
path "CMakeLists.txt"
}
}
sourceSets { main { jni.srcDirs = ['src/main/jni', 'src/main/jniLibs/'] } }
}
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.android.support:appcompat-v7:25.0.1'
testCompile 'junit:junit:4.12'
compile project(':openCVLibrary310dev')
}
和我的openCVLibrary310dev build.gradle
apply plugin: 'com.android.library'
android {
compileSdkVersion 25
buildToolsVersion "23.0.2"
defaultConfig {
ndk {
abiFilter("armeabi-v7a")
}
minSdkVersion 14
targetSdkVersion 25
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
}
}
}
我嘗試過的,主要是復制那些幫助其他人解決類似地雷問題的東西:
#set(CMAKE_SYSTEM_NAME Android)
要么
#set(CMAKE_TOOLCHAIN_FILE "Toolchain file" CACHE FILEPATH "C:/Libs/opencv_src/opencv/platforms/android.toolchain.cmake")
要么
#set( CMAKE_CXX_COMPILER "C:/Libs/android-ndk-r13b/toolchains/arm-linux-androideabi-4.9/prebuilt/windows-x86_64/bin/arm-linux-androideabi-g++.exe" )
在CMakeLists.txt中
和
splits {
abi {
enable true
reset()
include 'armeabi-v7a'
universalApk true
}
}
要么
tasks.getByPath(":app:linkMipsDebugRemoteDesktopSharedLibrary").enabled = false
在build.gradle中(我試過這兩個因為我不知道哪一個應該擁有它)。
除了最后一點代碼(task.getByPath ...),同步工作,但我無法構建。 對於最后一個,我甚至無法同步。
我也嘗試為mips重建庫,因為架構似乎是問題,但我不知道如何做到這一點。
我在哪里可以找到以下參數所在的文件:
{--build C:\Users\JambonSama\AndroidStudioProjects\customOCVtest\app\.externalNativeBuild\cmake\debug\mips64 --target native-lib}
建築時通過? 和/或如何讓Android Studio構建我的arm架構項目?
所以mips架構問題可以通過在android塊的末尾添加以下代碼到app的gradle.build來解決:
productFlavors {
armv7 {
ndk {
abiFilter "armeabi-v7a"
}
}
fat
}
但隨后出現了其他問題。 值得注意的是,該庫是使用Android Studio不喜歡的胡蘿卜素選項構建的,然后,gzlib錯過了,因此Android Studio無法構建和/或運行。 經過多次試驗,我終於實現了我的目標:在Windows上交叉編譯openCV與Android的額外模塊,並使用所述內置庫構建AS項目以使其正常工作 。 我記錄了我的整個過程,從下載openCV源代碼直到在我的arm-architected設備上運行我的應用程序,我只是將它粘貼到這里,以便任何需要這樣做的人。 以下說明主要基於本教程 (感謝編寫它的Zamrath Nizam)。 該教程唯一的問題是它可能有點舊,所以需要改變一些選項/步驟。
*第一:先決條件*
* SECOND:配置CMake *
通過“搜索”字段更改以下附加選項:
驗證是否正確設置了以下選項(通過“搜索”字段):
按'配置'
*第三:用mingw *編譯
*第四個:android項目*
轉到文件 - >新建 - >導入模塊...
更改openCVLibraryXXX(導入模塊)文件夾中build.gradle文件中的目標:
在openCVLibraryXXX(導入的模塊)文件夾中的build.gradle文件中:
將導入的庫作為依賴項添加到文件 - >'項目結構'中的'app'模塊
在'app / src / main'中創建一個jniLibs文件夾:
將OpenCV的庫從'opencv-source / platforms / android_arm / install / sdk / native / libs'復制到'AndroidStudioProjects / cOCV / app / src / main / jniLibs'文件夾中新創建的文件夾(jniLibs)中
在'opencv-contrib-source / modules / module_you_desperately_need / CMakeLists.txt'中,更改'ocv_define_module(module_you_desperately_need opencv opencv)以及'ocv_define_module(module_you_desperately_need opencv,其他一些模塊WRAP java)'
在CMakeLists.txt中,添加:
'add_library'塊之后和'find_library'塊之前的以下兩行:
include_directories(../opencv_src/opencv/platforms/build_android_armn/install/sdk/native/jni/include) link_directories(../AndroidStudioProjects/cOCVn/app/src/main/jniLibs/armeabi-v7a)
'find_library'塊之后和'target_link_libraries'塊之后的以下行:
file(GLOB PARTYLIBS "../opencv_src/opencv/platforms/build_android_armn/install/sdk/native/3rdparty/libs/armeabi-v7a/*.a") file(GLOB CVLIBS "../opencv_src/opencv/platforms/build_android_armn/install/sdk/native/libs/armeabi-v7a/*.a")
以下路徑,AS WRITTEN,在'target_link_libraries'中,在'native-lib'變量之后,在'$ {log-lib}'變量之前:
${CVLIBS} ${PARTYLIBS} ${CVLIBS}
在app的gradle.build中,添加以下代碼:
productFlavors { armv7 { ndk { abiFilter "armeabi-v7a" } } fat }
在android塊的末尾
在native-lib.cpp中:
在'stringFromJNI'函數中嘗試以下代碼(這個函數在創建項目時由AS自動生成)
cv::Mat test; cv::VideoCapture camera; camera.open(0); cv::Ptrcv::aruco::Dictionary dict = cv::aruco::getPredefinedDictionary(cv::aruco::DICT_6X6_250); cv::Mat marker; cv::aruco::drawMarker(dict, 25, 200, marker, 1); std::string hello = "Hello from C++"; return env-NewStringUTF(hello.c_str());
不要忘記以下內容包括:
#include jni.h #include string #include opencv2/aruco.hpp #include opencv2/videoio.hpp
時間來測試:
你很高興\\ o \\\\ O // o /
補充筆記 :
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