Android studio 1.3 NDK 无法解析 c++ header /代码

Question

我是 Android Studio 1.3.2 的新手，使用 NDK 更是如此。我正在尝试使用 OpenCV 2.4.11 和 C++。我正在使用 Gradle 2.6。

奇怪的是，到目前为止，OpenCV 没有在 C++ 代码中生成任何错误。就在我包含像 or 这样的 C++ header 时，它无法解析它们。 Unresolved Try...Catch 也是如此。同样，我在 2 周前开始使用 Android Studio，1 周前开始使用 NDK。我仍然不确定自己在做什么。

#include "jni.h"
#include <vector>
#include <string>
#include <opencv2/contrib/contrib.hpp>

#ifdef __cplusplus
extern "C" {
#endif

JNIEXPORT jlong JNICALL Java_face_rt_facert_FisherFaceRecognizer_createFisherFaceRecognizer_10(JNIEnv *env,
                                                                         jclass type) {

try {
    cv::Ptr<cv::FaceRecognizer> pfr = cv::createFisherFaceRecognizer();
    pfr.addref(); // this is for the 2.4 branch, 3.0 would need a different treatment here
    return (jlong) pfr.obj;
     } catch (...) {
    jclass je = env->FindClass("java/lang/Exception");
    env->ThrowNew(je, "sorry, dave..");
    }
    return 0;
}

#ifdef __cplusplus
}
#endif

项目的 build.gradle 文件:

apply plugin: 'com.android.model.application'

model {
android {
    compileSdkVersion = 23
    buildToolsVersion = "23.0.1"

    defaultConfig.with {
        applicationId = "face.rt.facert"
        minSdkVersion.apiLevel = 19
        targetSdkVersion.apiLevel = 19
        versionCode = 1
        versionName = "1.0.1"
    }

}

android.buildTypes {
    release {
        minifyEnabled = false
        proguardFiles += file('proguard-rules.txt')
    }
}

android.ndk { // keeping it to make AS correctly support C++ code editing and debugging
    moduleName = "Face"
    ldLibs += ['log']
    cppFlags += "-std=c++11"
    cppFlags += "-fexceptions"
    cppFlags += "-I${file("src/main/jni/prebuilts/include")}".toString()
    cppFlags  += "-I${file("C:/Android-dev/SDKs/OpenCV-android-sdk/sdk/native/jni/include")}".toString()
    cppFlags  += "-I${file("C:/Android-dev/SDKs/OpenCV-android-sdk/sdk/native/jni/include/opencv")}".toString()
    cppFlags  += "-I${file("C:/Android-dev/SDKs/OpenCV-android-sdk/sdk/native/jni/include/opencv2")}".toString()
    stl = "gnustl_shared" //"stlport_static"
}


android.productFlavors {
    // for detailed abiFilter descriptions, refer to "Supported ABIs" @
    // https://developer.android.com/ndk/guides/abis.html#sa
    create("arm") {
        ndk.with {
            abiFilters += "armeabi"

            File curDir = file('./')
            curDir = file(curDir.absolutePath)
            String libsDir = curDir.absolutePath+"\\src\\main\\jniLibs\\armeabi\\" //"-L" +

            ldLibs += libsDir + "libnative_camera_r4.3.0.so"
            ldLibs += libsDir + "libopencv_contrib.a"
            ldLibs += libsDir + "libopencv_core.a"
            ldLibs += libsDir + "libopencv_highgui.a"
            ldLibs += libsDir + "libopencv_imgproc.a"
            ldLibs += libsDir + "libopencv_info.so"
            ldLibs += libsDir + "libopencv_java.so"
            ldLibs += libsDir + "libopencv_legacy.a"
            ldLibs += libsDir + "libopencv_ml.a"
            ldLibs += libsDir + "libopencv_ts.a"

        }
    }
    create("armv7") {
        ndk.with {
            abiFilters += "armeabi-v7a"

            File curDir = file('./')
            curDir = file(curDir.absolutePath)
            String libsDir = curDir.absolutePath+"\\src\\main\\jniLibs\\armeabi-v7a\\" //"-L" +

            ldLibs += libsDir + "libnative_camera_r4.3.0.so"
            ldLibs += libsDir + "libopencv_contrib.a"
            ldLibs += libsDir + "libopencv_core.a"
            ldLibs += libsDir + "libopencv_highgui.a"
            ldLibs += libsDir + "libopencv_imgproc.a"
            ldLibs += libsDir + "libopencv_info.so"
            ldLibs += libsDir + "libopencv_java.so"
            ldLibs += libsDir + "libopencv_legacy.a"
            ldLibs += libsDir + "libopencv_ml.a"
            ldLibs += libsDir + "libopencv_ts.a"

        }
    }
    create("x86") {
        ndk.with {
            abiFilters += "x86"
        }
    }
    create("mips") {
        ndk.with {
            abiFilters += "mips"
        }
    }
    create("fat") {

    }

    // To include all cpu architectures, leaves abiFilters empty
    create("all")
}
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    compile 'com.android.support:appcompat-v7:23.0.1'
    compile project(':openCVLibrary2411')
}

这是我在项目中的依赖项:

classpath 'com.android.tools.build:gradle-experimental:0.3.0-alpha3'

编辑:

出于测试目的，从函数中删除了 Try...Catch。奇怪的是， vector 和字符串 header 现在已解析并正常工作。

但现在我在编译时遇到了一些关于 OpenCV 的错误。

Error:(16) undefined reference to `cv::createFisherFaceRecognizer(int, double)'

Error:(2607) undefined reference to `cv::fastFree(void*)'

Error:Execution failed for task ':app:linkArm64-v8aDebugAllFaceSharedLibrary'. A build operation failed. Linker failed while linking libFace.so.

Answer 1

我在我的 build.gradle 中发现:

    // To include all cpu architectures, leaves abiFilters empty
    create("all")

all 表示 32 位和 64 位。由于我的库只有 32 位，编译器找不到 64 位版本并失败。

我删除了这一行并且效果更好(仍然有一些错误但不是编译错误)