android studio中的Opencv不起作用？

Question

我正在嘗試將本機代碼添加到我的Android應用程序。 NDK可以很好地處理簡單的C++代碼，比如「來自C++的Hello」，但我需要使用openCV，而且我被卡住了。

項目生成輸出：

:app:generateArmDebugSources UP-TO-DATE 
:app:compileArmDebugJava UP-TO-DATE 
:app:compileArmDebugNdk 
D:/android-ndk-r10c/toolchains/arm-linux-androideabi-4.6/prebuilt/windows-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld.exe: D:\AndroidStudioProjects\OpenCVFeatureDetection\app\build\intermediates\ndk\arm\debug\obj/local/armeabi-v7a/objs-debug/jni_part/D_\AndroidStudioProjects\OpenCVFeatureDetection\app\src\main\jni\jni_part.o: in function cv::Mat::~Mat():jni_part.cpp(.text._ZN2cv3MatD2Ev+0x3c): error: undefined reference to 'cv::fastFree(void*)' 
D:/android-ndk-r10c/toolchains/arm-linux-androideabi-4.6/prebuilt/windows-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld.exe: D:\AndroidStudioProjects\OpenCVFeatureDetection\app\build\intermediates\ndk\arm\debug\obj/local/armeabi-v7a/objs-debug/jni_part/D_\AndroidStudioProjects\OpenCVFeatureDetection\app\src\main\jni\jni_part.o: in function cv::Mat::release():jni_part.cpp(.text._ZN2cv3Mat7releaseEv+0x6c): error: undefined reference to 'cv::Mat::deallocate()' 
D:/android-ndk-r10c/toolchains/arm-linux-androideabi-4.6/prebuilt/windows-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld.exe: D:\AndroidStudioProjects\OpenCVFeatureDetection\app\build\intermediates\ndk\arm\debug\obj/local/armeabi-v7a/objs-debug/jni_part/D_\AndroidStudioProjects\OpenCVFeatureDetection\app\src\main\jni\jni_part.o: in function cv::FastFeatureDetector::~FastFeatureDetector():jni_part.cpp(.text._ZN2cv19FastFeatureDetectorD1Ev+0xa0): error: undefined reference to 'cv::FeatureDetector::~FeatureDetector()' 
...25+ similar lines... 
collect2: ld returned 1 exit status 
make.exe: *** [D:\AndroidStudioProjects\OpenCVFeatureDetection\app\build\intermediates\ndk\arm\debug\obj/local/armeabi-v7a/libjni_part.so] Error 1 

FAILED 

FAILURE: Build failed with an exception. 

* What went wrong: 
Execution failed for task ':app:compileArmDebugNdk'. 
> com.android.ide.common.internal.LoggedErrorException: Failed to run command: 
    D:\android-ndk-r10c\ndk-build.cmd NDK_PROJECT_PATH=null APP_BUILD_SCRIPT=D:\AndroidStudioProjects\OpenCVFeatureDetection\app\build\intermediates\ndk\arm\debug\Android.mk APP_PLATFORM=android-21 NDK_OUT=D:\AndroidStudioProjects\OpenCVFeatureDetection\app\build\intermediates\ndk\arm\debug\obj NDK_LIBS_OUT=D:\AndroidStudioProjects\OpenCVFeatureDetection\app\build\intermediates\ndk\arm\debug\lib NDK_DEBUG=1 APP_STL=stlport_static APP_ABI=armeabi-v7a 
Error Code: 
    2 
FAILURE: Build failed with an exception. 

* What went wrong: 
Execution failed for task ':app:compileArmDebugNdk'. 
> com.android.ide.common.internal.LoggedErrorException: Failed to run command: 
    D:\android-ndk-r10c\ndk-build.cmd NDK_PROJECT_PATH=null APP_BUILD_SCRIPT=D:\AndroidStudioProjects\OpenCVFeatureDetection\app\build\inter 

mediates\ndk\arm\debug\Android.mk APP_PLATFORM=android-21 NDK_OUT=D:\AndroidStudioProjects\OpenCVFeatureDetection\app\build\intermediates\ndk\arm\debug\obj NDK_LIBS_OUT=D:\AndroidStudioProjects\OpenCVFeatureDetection\app\build\intermediates\ndk\arm\debug\lib NDK_DEBUG=1 APP_STL=stlport_static APP_ABI=armeabi-v7a 
Error Code: 
    2 
Output: 
    D:/android-ndk-r10c/toolchains/arm-linux-androideabi-4.6/prebuilt/windows-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld.exe: D:\AndroidStudioProjects\OpenCVFeatureDetection\app\build\intermediates\ndk\arm\debug\obj/local/armeabi-v7a/objs-debug/jni_part/D_\AndroidStudioProjects\OpenCVFeatureDetection\app\src\main\jni\jni_part.o: in function cv::Mat::~Mat():jni_part.cpp(.text._ZN2cv3MatD2Ev+0x3c): error: undefined reference to 'cv::fastFree(void*)' 
    D:/android-ndk-r10c/toolchains/arm-linux-androideabi-4.6/prebuilt/windows-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld.exe: D:\AndroidStudioProjects\OpenCVFeatureDetection\app\build\intermediates\ndk\arm\debug\obj/local/armeabi-v7a/objs-debug/jni_part/D_\AndroidStudioProjects\OpenCVFeatureDetection\app\src\main\jni\jni_part.o: in function cv::Mat::release():jni_part.cpp(.text._ZN2cv3Mat7releaseEv+0x6c): error: undefined reference to 'cv::Mat::deallocate()' 
    D:/android-ndk-r10c/toolchains/arm-linux-androideabi-4.6/prebuilt/windows-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/../../../../arm-linux-androideabi/bin/ld.exe: D:\AndroidStudioProjects\OpenCVFeatureDetection\app\build\intermediates\ndk\arm\debug\obj/local/armeabi-v7a/objs-debug/jni_part/D_\AndroidStudioProjects\OpenCVFeatureDetection\app\src\main\jni\jni_part.o: in function cv::FastFeatureDetector::~FastFeatureDetector():jni_part.cpp(.text._ZN2cv19FastFeatureDetectorD1Ev+0xa0): error: undefined reference to 'cv::FeatureDetector::~FeatureDetector()' 
    ...and 25+ similar lines again... 
collect2: ld returned 1 exit status 
    make.exe: *** [D:\AndroidStudioProjects\OpenCVFeatureDetection\app\build\intermediates\ndk\arm\debug\obj/local/armeabi-v7a/libjni_part.so] Error 1 


* Try: 
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. 



BUILD FAILED 

Total time: 12.261 secs 

我注意到了類似的問題https://stackoverflow.com/a/22427267/4595220，但我還沒有找到一個解決方案。我做錯了什麼？

的build.gradle

apply plugin: 'com.android.application' 

android { 
    compileSdkVersion 21 
    buildToolsVersion "21.1.2" 

    defaultConfig { 
     applicationId "com.gogiant.opencvfeaturedetection" 
     minSdkVersion 15 
     targetSdkVersion 21 
    versionCode 1 
    versionName "1.0" 

    ndk { 
     moduleName "jni_part" 
     cFlags "-DANDROID_NDK" 
     ldLibs "log" 
     stl "stlport_static" 
    } 
} 

buildTypes { 
    release { 

     minifyEnabled false 
     proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' 
    } 

    // make per-variant version code 
    applicationVariants.all { variant -> 
     // get the single flavor 
     def flavorVersion = variant.productFlavors.get(0).versionCode 

     // set the composite code 
     variant.mergedFlavor.versionCode = flavorVersion * 1000000 + defaultConfig.versionCode 
    } 

    productFlavors { 
     x86 { 
      ndk { 
       abiFilter "x86" 
      } 

      // this is the flavor part of the version code. 
      // It must be higher than the arm one for devices supporting 
      // both, as x86 is preferred. 
      versionCode = 3 
     } 
     arm { 
      ndk { 
       abiFilter "armeabi-v7a" 
      } 
      versionCode = 2 
     } 
     mips { 
      ndk { 
       abiFilter "mips" 
      } 
      versionCode = 1 
     } 
     fat { 
      // fat binary, lowest version code to be 
      // the last option 
      versionCode = 0 
     } 
    } 

     debug.jniDebuggable true 
    } 
} 


dependencies { 
    compile fileTree(dir: 'libs', include: ['*.jar']) 
    compile 'com.android.support:appcompat-v7:21.0.3' 
    compile 'com.android.support:support-v4:21.0.3' 
    compile project(':libraries:opencv') 
} 

Android.mk

LOCAL_PATH := $(call my-dir) 
include $(CLEAR_VARS) 
OPENCV_LIB_TYPE:=STATIC 
OPENCV_INSTALL_MODULES:=on 
OPENCV_CAMERA_MODULES:=off 


include D:\OpenCV-2.4.9-android-sdk\sdk\native\jni\OpenCV.mk 

LOCAL_C_INCLUDES += D:\AndroidStudioProjects\OpenCVFeatureDetection\libraries\opencv\include 


LOCAL_MODULE := jni_part 
LOCAL_SRC_FILES := jni_part.cpp 

LOCAL_STATIC_LIBRARIES += libopencv_contrib libopencv_legacy libopencv_ml libopencv_stitching libopencv_nonfree libopencv_objdetect libopencv_videostab libopencv_calib3d libopencv_photo libopencv_video libopencv_features2d libopencv_highgui libopencv_androidcamera libopencv_flann libopencv_imgproc libopencv_ts libopencv_core 

LOCAL_LDLIBS += -llog -ldl 
include $(BUILD_SHARED_LIBRARY) 

Application.mk

APP_STL := gnustl_static 
APP_CPPFLAGS := -frtti -fexceptions 
APP_ABI := all 
APP_PLATFORM := android-8 

項目結構：http://i.stack.imgur.com/Yg5Jl.png 完整的項目：https://yadi.sk/d/brR5GUjber2Qo

感謝您的幫助。

Answer 1

我測試了你的項目。爲了使它成功構建，我必須刪除文件夾app/src/main/jni和文件夾app/src/main/3rdparty以及文件夾app/libs /中的文件opencvlibrary-2.4.9.jar。看起來你的項目中有幾個opencv庫（因此彼此衝突）。

希望這會有所幫助。

Answer 2

您是否嘗試過使用Eclipse構建項目？我在Intellij上使用OpenCV做了一些工作，並且遇到了一些麻煩使它工作，這也是NDK的問題。

Answer 3

Android Studio和Android gradle插件1.1.0中的當前NDK支持受到限制並且已被棄用。自動生成的Makefile被即時使用，並且不支持從NDK源鏈接外部NDK庫（如OpenCV）。

您應該刪除build.gradle中的ndk{}塊，並停用當前的NDK集成，以便直接依賴ndk-build和Makefiles。您還可以使用，而不是分裂的口味，以生成每個ABI的APK，就像這個要點：https://gist.github.com/ph0b/9e59058ac59cac104398

你的build.gradle會是這樣的：

import org.apache.tools.ant.taskdefs.condition.Os 

apply plugin: 'com.android.application' 

android { 
    compileSdkVersion 21 
    buildToolsVersion "21.1.2" 

    defaultConfig { 
     applicationId "com.gogiant.opencvfeaturedetection" 
     minSdkVersion 15 
     targetSdkVersion 21 
     versionCode 1 
     versionName "1.0" 
    } 

    sourceSets.main { 
     jniLibs.srcDir 'src/main/libs' 
     jni.srcDirs = [] //disable automatic ndk-build call 
    } 

    buildTypes { 
     release { 
      minifyEnabled false 
      proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' 
     } 
    } 

    splits { 
     abi { 
      enable true 
      reset() 
      include 'x86', 'armeabi-v7a', 'mips' //select ABIs to build APKs for 
      universalApk true //generate an additional APK that contains all the ABIs 
     } 
    } 

    project.ext.versionCodes = ['armeabi':1, 'armeabi-v7a':2, 'arm64-v8a':3, 'mips':5, 'mips64':6, 'x86':8, 'x86_64':9] //versionCode digit for each supported ABI, with 64bit>32bit and x86>armeabi-* 

    android.applicationVariants.all { variant -> 
    // assign different version code for each output 
     variant.outputs.each { output -> 
      output.versionCodeOverride = 
project.ext.versionCodes.get(output.getFilter(com.android.build.OutputFile.ABI), 0) * 1000000 + defaultConfig.versionCode 
     } 
    } 

    // call regular ndk-build(.cmd) script from app directory 
    task ndkBuild(type: Exec) { 
     if (Os.isFamily(Os.FAMILY_WINDOWS)) { 
      commandLine 'ndk-build.cmd', '-C', file('src/main').absolutePath 
     } else { 
      commandLine 'ndk-build', '-C', file('src/main').absolutePath 
     } 
    } 

    tasks.withType(JavaCompile) { 
     compileTask -> compileTask.dependsOn ndkBuild 
    } 
} 

dependencies { 
    compile fileTree(dir: 'libs', include: ['*.jar']) 
    compile 'com.android.support:appcompat-v7:21.0.3' 
    compile 'com.android.support:support-v4:21.0.3' 
    compile project(':libraries:opencv') 
}