Android NDK: No Implementation Found For Native Xxxxxx

I do a project in using Tess-two, i want to use the method pixConvertRGBToLuminance, but it always the error: No implementation found for native Lcom/googlecode/leptonica/android/

Solution 1:

Another question where the answer is C++ name mangling - declare your function as èxtern "C"

Solution 2:

extern "C" jint Java_com_googlecode_letonica_android_Pix_nativePixConvertRGBToLuminance(JNIEnv *env,
    jclass clazz, jint nativePixs){

PIX *pixs = (PIX *)nativePixs;

LOGE("------------------>Failed to find native pixConvertRGBToLuminance File");
PIX *pixd = pixConvertRGBToLuminance(pixs);
return (jint) pixd;
}

Refer Calling a Java function from C++ on Android over JNI