OpenCv 与 Android Studio 2.2+ 使用带有 cmake 的新 gradle - 未定义的参考

Question

我在使用原生 OpenCv 3.0.0 和 Android Studio 2.2 时遇到问题，它支持新的 ndk，即使用 CMAKE 构建脚本。以下是我得到的错误。我的 gradle 或 cmake 文件中是否缺少任何内容？请告诉我。

错误：失败：构建失败并出现异常。

• 出了什么问题： 任务 ':app:externalNativeBuildDebug' 执行失败。

  构建命令失败。 使用参数执行“C:\Users\User\AppData\Local\Android\sdk\cmake\3.6.3155560\bin\cmake.exe”时出错 {--build E:\OpenCvAndroid\OPecvTry2CSupport\app.externalNativeBuild\cmake\调试\mips64 --target native-lib} [1/1] 链接 CXX 共享库 ..\obj\mips64\libnative-lib.so 失败： cmd.exe /C "cd . && C:\Users\User\AppData\Local\Android\sdk\ndk-bundle\toolchains\llvm\prebuilt\windows-x86_64\bin\clang++.exe -target mips64el-none -linux-android -gcc-toolchain C:/Users/User/AppData/Local/Android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/windows-x86_64 --sysroot=C:/Users /User/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 -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 -shared -Wl,-soname,libnative -lib.so -o ..\obj\mips64\libnative-lib.so CMakeFiles/native-lib.dir/src/main/cpp/native-lib.cpp.o -llog -lm "C:/Users/User /AppData/Local/Android/sdk/ndk-bundle/sources/cxx-stl/gnu-libstdc++/4.9/libs/mips64/libgnustl_static.a" && 光盘。” CMakeFiles/native-lib.dir/src/main/cpp/native-lib.cpp.o：在函数~Mat': E:/OpenCVSdk/sdk/native/jni/include\opencv2/core/mat.hpp:278: undefined reference tocv::fastFree(void*)' CMakeFiles/native-lib.dir/src/main/cpp/native-lib.cpp.o：在函数cv::Mat::release()': E:/OpenCVSdk/sdk/native/jni/include\opencv2/core/mat.hpp:367: undefined reference tocv::Mat::deallocate()' clang++.exe：错误：链接器命令失败，退出代码为 1（使用 -v 查看调用） 忍者：构建停止：子命令失败。

还有我的 Cmake.txt

 cmake_minimum_required(VERSION 3.4.1)
 add_library( native-lib
         SHARED
         src/main/cpp/native-lib.cpp )
include_directories(E\:\\OpenCVSdk\\sdk\\native\\jni\\include )
find_library( log-lib log )
target_link_libraries(native-lib ${log-lib} )

还有我的 Gradle 构建文件

 {    apply plugin: 'com.android.application'

 android {

compileSdkVersion 24
buildToolsVersion "24.0.2"
defaultConfig {
    applicationId "viki.opecvtry2csupport"
    minSdkVersion 16
    targetSdkVersion 24
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"



    externalNativeBuild {
        cmake {
            cppFlags ""

        }
    }
}

Answer 1

我通过将“lib_opencv”库添加到 target_link_libraries 解决了我的问题

target_link_libraries(
                   native-lib lib_opencv #Just add the lib_opencv
                   ${log-lib} )

别忘了Link Gradle to your native library

我的完整 CMakeList.txt

cmake_minimum_required(VERSION 3.4.1)

add_library( native-lib
             SHARED
             src/main/cpp/native-lib.cpp )

find_library( log-lib
              log )

target_link_libraries(native-lib lib_opencv
                       ${log-lib} )

set(CMAKE_VERBOSE_MAKEFILE on)
add_library(lib_opencv SHARED IMPORTED)
set_target_properties(lib_opencv PROPERTIES IMPORTED_LOCATION /PROJECT_PATH/openCVLibrary320/src/main/jniLibs/${ANDROID_ABI}/libopencv_java3.so)

include_directories(/OpenCV-android-sdk/sdk/native/jni/include)

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++11")

Answer 2

设置OpenCV_DIR 对我来说适用于 OpenCV 3.1 和 AS 2.2 以及最新的 Gradle 插件。这是我的 CMakeLists.txt 的相关部分。

cmake_minimum_required(VERSION 3.6)

SET(OpenCV_DIR $ENV{HOME}/AndroidDevelopment/opencv-3.1.0/sdk/native/jni)

find_package(OpenCV REQUIRED)
message(STATUS "opencv found: ${OpenCV_LIBS}")

include_directories(${CMAKE_CURRENT_SOURCE_DIR}
                    ${OpenCV_DIR}/include/)
[...]
target_link_libraries(myTarget log ${OpenCV_LIBS} m z android )