java.lang.UnsatisfiedLinkError：在Android中找不到本机方法

Question

Could someone help me locate my error, I have looked at looked I can't seem to find it, I am trying to run my code but it keeps giving me the error java.lang.UnsatisfiedLinkError: Native method not found: nemo.lungu.receiptor.scanlibrary.ScanActivity.getPoints:(Landroid/graphics/Bitmap;)[F below is my activity method getPoints() :

   public native float[] getPoints(Bitmap bitmap); 

the Header version of the method getPoints() :

JNIEXPORT jfloatArray JNICALL  Java_nemo_lungu_receiptor_scanlibrary_ScanActivity_getPoints
(JNIEnv *, jobject, jobject);

and finally the implementation of the method getPoints() in my .cpp file:

JNIEXPORT jfloatArray JNICALL Java_nemo_lungu_receiptor_scanlibrary_ScanActivity_getPoints
(JNIEnv *env, jobject thiz,jobject bitmap)
{
__android_log_print(ANDROID_LOG_VERBOSE, APPNAME, "Scaning getPoints");
int ret;
AndroidBitmapInfo info;
void* pixels = 0;

if ((ret = AndroidBitmap_getInfo(env, bitmap, &info)) < 0) {
    __android_log_print(ANDROID_LOG_VERBOSE, APPNAME,"AndroidBitmap_getInfo() failed ! error=%d", ret);
    return 0;
}

if (info.format != ANDROID_BITMAP_FORMAT_RGBA_8888 )
{       __android_log_print(ANDROID_LOG_VERBOSE, APPNAME,"Bitmap format is not RGBA_8888!");
    return 0;
}

if ((ret = AndroidBitmap_lockPixels(env, bitmap, &pixels)) < 0) {
    __android_log_print(ANDROID_LOG_VERBOSE, APPNAME,"AndroidBitmap_lockPixels() failed ! error=%d", ret);
}

// init our output image
Mat mbgra(info.height, info.width, CV_8UC4, pixels);
vector<Point> img_pts = getPoints(mbgra);

jfloatArray jArray = env->NewFloatArray(8);

if (jArray != NULL)
{
    jfloat *ptr = env->GetFloatArrayElements(jArray, NULL);

    for (int i=0,j=i+4; j<8; i++,j++)
    {
        ptr[i] = img_pts[i].x;
        ptr[j] = img_pts[i].y;
    }
    env->ReleaseFloatArrayElements(jArray, ptr, NULL);
}
AndroidBitmap_unlockPixels(env, bitmap);
return jArray;

}

Am loading the library like:

  static {

    System.loadLibrary("myLibraryName");
   }

Which seems to load successfully as it gives me the message Added shared lib /data/app-lib/nemo.lungu.receiptor-2/myLibraryName.so 0xa4fe5e78 but again after that it gives me another message to say No JNI_OnLoad found in /data/app-lib/nemo.lungu.receiptor-2/myLibraryName.so 0xa4fe5e78, skipping init so I do not know if that is the cause or something else.

Answer 1

我需要将extern "C"放在我的getPoints()前面，因为JNI无法理解C++命名转换，因此我的.cpp文件中的getPoints()方法需要看起来像extern C JNIEXPORT jfloatArray JNICALL Java_nemo_lungu_receiptor_scanlibrary_ScanActivity_getPoints (JNIEnv *env, jobject thiz,jobject bitmap) {//method implementation}