java.lang.UnsatisfiedLinkError：运行时调用该本地方法时未找到本地方法 Eclipse

Question

我是 android 编程新手，所以我尝试编写一个简单的程序，可以从 java 调用 jni 文件夹本机 cpp 文件方法。虽然我尝试运行 OPENCV 示例并尝试了相同的调用方式，但没有一个m 甚至没有计算出 OpenCV 教程 2 - 混合处理。它在我的模拟器中启动并崩溃。

com_rukna_myfirstandroidimageapp_MainActivity.h

extern "C"{
 * Class:     com_rukna_myfirstandroidimageapp_MainActivity
 * Method:    getStringfromNative
 * Signature: (I)Ljava/lang/String;

JNIEXPORT jstring JNICALL Java_com_rukna_myfirstandroidimageapp_MainActivity_getStringfromNative
  (JNIEnv *, jobject, jint);
}

CPPCALL.cpp

#include <com_rukna_myfirstandroidimageapp_MainActivity.h>     
#include <opencv2/core/core.hpp>         
#include <opencv2/imgproc/imgproc.hpp>
JNIEXPORT jstring JNICALL Java_com_rukna_myfirstandroidimageapp_MainActivity_getStringfromNative (JNIEnv *env , jobject obj, jint src)     
{
        return (env)->NewStringUTF("HELLO from JNI CPPCALL !!");     
}

使用命令提示符我也在 MYProject/bin/classpath/javap -s -p MainActivity
中使用过 ----这个我有很多---

public native java.lang.String getStringfromNative(int);    
  descriptor: (I)Ljava/lang/String;

但是当我像下面这样从 MainActivity 调用此方法时

package com.rukna.myfirstandroidimageapp;    
import library    
public class MainActivity extends Activity {   
/* some declarations and other functions */   
int a = 0;int b = 1;      
String s = getStringfromNative( a); /*---> error when call for the cpp method*/   
_field.setText(s);  
_field.setSelection(_field.getText().toString().length());  


public native String getStringfromNative(int a);

    static {
        if (!OpenCVLoader.initDebug()) {
            // Handle initialization error
        }
        else{
        System.loadLibrary("MyLib");}
    }
}

运行应用程序时出现以下错误：

java.lang.UnsatisfiedLinkError: Native method not found: com.rukna.myfirstandroidimageapp.MainActivity.getStringfromNative:(I)Ljava/lang/String;

Android.mk

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

#OPENCV_CAMERA_MODULES:=off
#OPENCV_INSTALL_MODULES:=on
#OPENCV_LIB_TYPE:=SHARED
#OPENCV_LIB_TYPE:=STATIC
# OpenCV
OPENCV_CAMERA_MODULES:=on
OPENCV_INSTALL_MODULES:=on
OPENCV_LIB_TYPE:=STATIC
include D:/OpenCV-2.4.11-android-sdk/sdk/native/jni/OpenCV.mk


#LOCAL_MODULE    := CLAHE_test
LOCAL_MODULE    := MyLib
LOCAL_SRC_FILES := CPPCALL.cpp
#LOCAL_SRC_FILES := CLAHE_test.cpp
#LOCAL_C_INCLUDES := $(LOCAL_PATH)
LOCAL_LDLIBS +=  -llog

include $(BUILD_SHARED_LIBRARY)

Application.mk

APP_STL := gnustl_static
APP_CPPFLAGS := -frtti -fexceptions
APP_ABI := x86
APP_PLATFORM := android-19

当我签入 myproject.apk 时，我在 MyFirstAndroidImageApp.apk\lib\x86

下找到

libhydrogen.so
libimageutils.so
liblept.so
libMyLib.so
libnative_camera_r2.3.3.so
libnative_camera_r3.0.1.so
libnative_camera_r4.0.3.so
libnative_camera_r4.1.1.so
libnative_camera_r4.2.0.so
libnative_camera_r4.3.0.so
libnative_camera_r4.4.0.so
libopticalflow.so
libtess.so

项目属性->C/C++ 通用-> 路径和符号-> 包含-> GNU C++

${NDKROOT}/platforms/android-9/arch-arm/usr/include
${NDKROOT}/sources/cxx-stl/gnu-libstdc++/4.6/include
${NDKROOT}/sources/cxx-stl/gnu-libstdc++/4.6/libs/armeabi-v7a/include
${NDKROOT}/toolchains/arm-linux-androideabi-4.8/prebuilt/windows-x86_64/lib/gcc/arm-linux-androideabi/4.8/include
D:/OpenCV-2.4.11-android-sdk/sdk/native/jni/include
D:\android-ndk-r10d\platforms\android-19\arch-x86\usr\include

帮助我，当我在没有任何参数的情况下调用相同的方法然后它运行正常我不明白为什么.....如果是，我是否需要给构造函数一种东西，如果是，那么在哪里以及如何？

Answer 1

您是否尝试在 Application.mk 中修改 APP_ABI := armeabi-v7a。另外，如果cpp编译成功，你应该在libs/armeabi-v7a中找到so文件