首页 ❯

Unsatisfiedlinkerror OpenALPR test project for android

android java c++ android-ndk
2022-09-01 01:40:39

几天来，我正在尝试为Android构建OpenALPR示例项目。它生成并启动，但在调用本机方法来识别它之后，会例外：

java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:299)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
at java.util.concurrent.FutureTask.run(FutureTask.java:239)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
at java.lang.Thread.run(Thread.java:838)

Caused by: java.lang.UnsatisfiedLinkError: Native method not found: org.openalpr.AlprJNIWrapper.recognizeWithCountryRegionNConfig:(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;I)Ljava/lang/String;
at org.openalpr.AlprJNIWrapper.recognizeWithCountryRegionNConfig(Native Method)
at org.openalpr.app.AlprFragment$AlprTask.doInBackground(AlprFragment.java:78)
at org.openalpr.app.AlprFragment$AlprTask.doInBackground(AlprFragment.java:1)
at android.os.AsyncTask$2.call(AsyncTask.java:287)
at java.util.concurrent.FutureTask.run(FutureTask.java:234)
... 4 more

我什么也做不了，它一直都出现。

Application.mk

APP_ABI := armeabi-v7a
APP_CPPFLAGS := -frtti -fexceptions
APP_STL := gnustl_static

Android.mk 在我所有的尝试之后

LOCAL_PATH := $(call my-dir)
LIB_PATH := $(LOCAL_PATH)/../libs/armeabi-v7a

include $(CLEAR_VARS)

LOCAL_MODULE := leptonica
LOCAL_SRC_FILES := 3rdparty/liblept.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)

LOCAL_MODULE := tesseract
LOCAL_SRC_FILES := 3rdparty/libtess.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)

LOCAL_MODULE := simpleini
LOCAL_SRC_FILES := 3rdparty/libsimpleini.a
include $(PREBUILT_STATIC_LIBRARY)

include $(CLEAR_VARS)

LOCAL_MODULE := support
LOCAL_SRC_FILES := 3rdparty/libsupport.a
include $(PREBUILT_STATIC_LIBRARY)

include $(CLEAR_VARS)

LOCAL_MODULE := openalpr
LOCAL_SRC_FILES := 3rdparty/libopenalpr-static.a
include $(PREBUILT_STATIC_LIBRARY)

include $(CLEAR_VARS)

OPENCV_INSTALL_MODULES:=on
OPENCV_CAMERA_MODULES:=off

include d:\Other\robovisor_mobile\OpenCV-android-sdk\sdk\native\jni\OpenCV.mk

LOCAL_MODULE := openalpr-native
SOURCE_LIST := $(wildcard $(LOCAL_PATH)/*.cpp)
HEADER_LIST := $(wildcard $(LOCAL_PATH)/*.h)
LOCAL_SRC_FILES := AlprJNIWrapper.cpp
LOCAL_SRC_FILES += $(HEADER_LIST:$(LOCAL_PATH)/%=%)
LOCAL_SRC_FILES += $(SOURCE_LIST:$(LOCAL_PATH)/%=%)
LOCAL_EXPORT_C_INCLUDES += /home/sujay/builds/src/openalpr/src/openalpr
LOCAL_EXPORT_C_INCLUDES += /home/sujay/builds/src/OpenCV-2.4.9-android-sdk/sdk/native/include
FILE_LIST := $(foreach dir, $(LOCAL_EXPORT_C_INCLUDES), $(wildcard $(dir)/*.cpp))
LOCAL_SRC_FILES := $(FILE_LIST:$(LOCAL_PATH)/%=%)

LOCAL_C_INCLUDES += /home/sujay/builds/src/openalpr/src/openalpr
LOCAL_C_INCLUDES += /home/sujay/builds/src/OpenCV-2.4.9-android-sdk/sdk/native/include
LOCAL_C_INCLUDES += /home/sujay/tools/android-ndk-r10/platforms/android-19/arch-arm/usr/include
LOCAL_SHARED_LIBRARIES += tesseract leptonica
LOCAL_STATIC_LIBRARIES += openalpr support simpleini
LOCAL_LDLIBS := -llog

include $(BUILD_SHARED_LIBRARY)

AlprJNIWrapper.cpp包含我所需的本机函数

/**
 * Created by sujay on 13/11/14.
 */
#include <string>
#include <sstream>
#include <cstdio>
#include <iostream>

// openCV includes
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"

// open alpr includes
#include "support/filesystem.h"
#include "support/timing.h"
#include "alpr.h"
#include "cjson.h"

#include "AlprJNIWrapper.h"
#include "AlprNative.h"

using namespace alpr;

JNIEXPORT jstring JNICALL Java_org_openalpr_AlprJNIWrapper_recognize(JNIEnv *env,
        jobject object, jstring jimgFilePath, jint jtopN)
{
    jstring defaultCountry = env->NewStringUTF("us");
    jstring defaultRegion = env->NewStringUTF("");
    jstring defaultConfigFilePath = env->NewStringUTF(CONFIG_FILE);
    return _recognize(env, object, defaultCountry, defaultRegion, jimgFilePath, defaultConfigFilePath, jtopN);
}

JNIEXPORT jstring JNICALL Java_org_openalpr_AlprJNIWrapper_recognizeWithCountryNRegion(
        JNIEnv *env, jobject object, jstring jcountry,
        jstring jregion, jstring jimgFilePath, jint jtopN)
{
    jstring defaultConfigFilePath = env->NewStringUTF(CONFIG_FILE);
    return _recognize(env, object, jcountry, jregion, jimgFilePath, defaultConfigFilePath, jtopN);
}

JNIEXPORT jstring JNICALL Java_org_openalpr_AlprJNIWrapper_recognizeWithCountryRegionNConfig
  (JNIEnv *env, jobject object, jstring jcountry, jstring jregion,
          jstring jimgFilePath, jstring jconfigFilePath, jint jtopN)
{
    return _recognize(env, object, jcountry, jregion, jimgFilePath, jconfigFilePath, jtopN);
}

jstring _recognize(JNIEnv *env, jobject object,
        jstring jcountry, jstring jregion, jstring jimgFilePath,
        jstring jconfigFilePath, jint jtopN)
{

    const char* countryChars = env->GetStringUTFChars(jcountry, NULL);

    std::string country(countryChars);

    env->ReleaseStringUTFChars(jcountry, countryChars);

    if(country.empty())
    {
        country = "us";
    }

    const char* configFilePathChars = env->GetStringUTFChars(jconfigFilePath, NULL);

    std::string configFilePath(configFilePathChars);

    env->ReleaseStringUTFChars(jconfigFilePath, configFilePathChars);

    if(configFilePath.empty())
    {
        configFilePath = "/etc/openalpr/openalpr.conf";
    }

    const char* imgFilePath = env->GetStringUTFChars(jimgFilePath, NULL);

    int topN = jtopN;

    std::string response = "";

    cv::Mat frame;
    Alpr alpr(country, configFilePath);

    const char* regionChars = env->GetStringUTFChars(jregion, NULL);

    std::string region(regionChars);

    env->ReleaseStringUTFChars(jregion, regionChars);

    if(region.empty())
    {
        alpr.setDetectRegion(true);
        alpr.setDefaultRegion(region);
    }


    alpr.setTopN(topN);

    if (alpr.isLoaded() == false) {
        env->ReleaseStringUTFChars(jimgFilePath, imgFilePath);
        response = errorJsonString("Error initializing Open Alpr");
        return env->NewStringUTF(response.c_str());
    }

    if(fileExists(imgFilePath))
    {
        frame = cv::imread(imgFilePath);
        response = detectandshow(&alpr, frame, "");
    }
    else
    {
        response = errorJsonString("Image file not found");
    }
    env->ReleaseStringUTFChars(jimgFilePath, imgFilePath);
    return env->NewStringUTF(response.c_str());
}

JNIEXPORT jstring JNICALL Java_org_openalpr_AlprJNIWrapper_version
  (JNIEnv *env, jobject object)
{
    return env->NewStringUTF(Alpr::getVersion().c_str());
}

std::string detectandshow(Alpr* alpr, cv::Mat frame, std::string region) 
{
    std::vector < uchar > buffer;
    std::string resultJson = "";
    cv::imencode(".bmp", frame, buffer);

    std::vector < char > buffer1;

    for(std::vector < uchar >::iterator i = buffer.begin(); i < buffer.end(); i++) {
        buffer1.push_back(*i);
    }

    timespec startTime;
    getTimeMonotonic(&startTime);

    //std::vector < AlprResults > results = alpr->recognize(buffer);
    AlprResults results = alpr->recognize(buffer1);

    timespec endTime;
    getTimeMonotonic(&endTime);
    double totalProcessingTime = diffclock(startTime, endTime);

    //if (results.size() > 0)
    {
        resultJson = alpr->toJson(results/*, totalProcessingTime*/);
    }

    return resultJson;
}

std::string errorJsonString(std::string msg) 
{
    cJSON *root;
    root = cJSON_CreateObject();
    cJSON_AddTrueToObject(root, "error");
    cJSON_AddStringToObject(root, "msg", msg.c_str());

    char *out;
    out = cJSON_PrintUnformatted(root);

    cJSON_Delete(root);

    std::string response(out);

    free(out);
    return response;
}

AlprJNIWrapper.java调用本机方法

/**
 * 
 */
package org.openalpr;

/**
 * @author sujay
 *
 */
public class AlprJNIWrapper implements Alpr {

        static { 
            System.loadLibrary("lept");
            System.loadLibrary("tess");
            System.loadLibrary("opencv_java");
            System.loadLibrary("openalpr-native");
        }

    /* (non-Javadoc)
     * @see org.openalpr.Alpr#recognize(java.lang.String, int)
     */
    @Override
    public native String recognize(String imgFilePath, int topN);

    /* (non-Javadoc)
     * @see org.openalpr.Alpr#recognizeWithCountryNRegion(java.lang.String, java.lang.String, java.lang.String, int)
     */
    @Override
    public native String recognizeWithCountryNRegion(String country, String region,
            String imgFilePath, int topN);

    /* (non-Javadoc)
     * @see org.openalpr.Alpr#recognizeWithCountryRegionNConfig(java.lang.String, java.lang.String, java.lang.String, java.lang.String, int)
     */
    @Override
    public native String recognizeWithCountryRegionNConfig(String country,
            String region, String imgFilePath, String configFilePath, int topN);

    /*
     * (non-Javadoc)
     * @see org.openalpr.Alpr#version()
     */
    @Override
    public native String version();
}

编辑

我的手机上有关于处理器的信息。

Processor       : ARMv7 Processor rev 3 (v7l)
processor       : 0
BogoMIPS        : 1993.93

Features        : swp half thumb fastmult vfp edsp thumbee neon vfpv3 tls vfpv4
idiva idivt
CPU implementer : 0x41
CPU architecture: 7
CPU variant     : 0x0
CPU part        : 0xc07
CPU revision    : 3

再次编辑

我试图在结果文件中获取有关函数的信息，我得到了：.so

Symbol table '.dynsym' contains 6 entries:
   Num:    Value  Size Type    Bind   Vis      Ndx Name
     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND 
     1: 00000000     0 FUNC    GLOBAL DEFAULT  UND __cxa_finalize
     2: 00000000     0 FUNC    GLOBAL DEFAULT  UND __cxa_atexit
     3: 00002004     0 NOTYPE  GLOBAL DEFAULT  ABS _edata
     4: 00002004     0 NOTYPE  GLOBAL DEFAULT  ABS __bss_start
     5: 00002004     0 NOTYPE  GLOBAL DEFAULT  ABS _end

我从以下来源获得：

<ndk_path>\toolchains\arm-linux-androideabi-4.8\prebuilt\windows\bin>arm-linux-androideabi-readelf.exe 
-Ws <projects_path>\libs\armeabi-v7a\libopenalpr-native.so

我做错了什么吗？或者文件中真的没有我的函数？.so


答案 1

可能有几个问题。
首先，您在不受支持的设备上运行示例，例如，如果为 armeabi-v7 构建的 lib（由于 make 文件中的设置，它肯定是这样），并且您的设备是 intel x86 或低于 7 armeabi 版本，等等。
此外，
编译的 NDK lib 对包敏感，因此，如果您将 JNI 类放入其他包中，它也不会起作用。
此外，本机库 .so-file 必须放置在项目的正确位置，而不是通常放置 jar-lib 的 libs 文件夹。它有点像Android工作室的文件夹：APP_ABI := armeabi-v7a

...\src\main\jniLibs\aremabi-v7a\libYourLib.so （for aremabi-v7a version）
...\src\main\jniLibs\x86\libYourLib.so （for x86 version and etc）

更新：
不要忘记尊重最低API级别，即19。应用程序无法在具有较低API级别的设备上工作，我的意思是您可以在项目中更改最低API级别 - 不要这样做。
这里的问题是，它的名字中有一个破折号字符。Dash 是 AOS 中用于资源命名的受限字符。所以我用“_”替换了它，应用程序现在可以工作，并在这里替换它：libopenalpr-native.so-

System.loadLibrary("openalpr_native");

我没有使用您的 .so 版本，而只使用了项目一中包含的版本。
更新
看一看：http://prntscr.com/6w6qfx 与原始的1.7Mb相比，您的lib仅为5kb，那么肯定有问题。它在评论中解释了您的问题：

为什么 System.loadLibrary（“openalpr-native”） 上没有错误;？我只是无法理解这种情况 - 创建 libopenalpr-native.so 文件，它加载到程序，通过没有办法。

你能只使用示例项目中包含的原始库吗？只是为了测试。


答案 2

由于名称不匹配，在库中找不到正确的方法，您应该将 JNI 函数代码包装在C++代码中。extern "C"


推荐
更多 »
标签
更多 »
php pass-by-reference optional-parameters default-value javascript arrays dom function string object serialization tostring visibility syntax jslint use-strict operators equality equality-operator identity-operator datetime timestamp date-arithmetic redirect angularjs loops foreach iteration scope variables
推荐
更多 »