Question

我在使用Tess-2做一个项目，我想使用方法pixConvertRGBToLuminance，但它始终是错误：

No implementation found for native Lcom/googlecode/leptonica/android/Pix;.nativePixConvertRGBToLuminance:(I)I.

我的代码Java是：

public static Pix pixConvertRGBToLuminance(Pix pixs){
    if (pixs == null)
        throw new IllegalArgumentException("Source pix must be non-null");

    int nativePixd = nativePixConvertRGBToLuminance(pixs.getNativePix());

    return new Pix(nativePixd);

}

我的代码.cpp是：

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;
}

Leptonica的原始代码是：

PIX * pixConvertRGBToLuminance(PIX *pixs)
{
  return pixConvertRGBToGray(pixs, 0.0, 0.0, 0.0);
}`

那么为什么我总是有这个错误呢？Thx。

Answer 1

答案是C ++名称修改的另一个问题 - 将您的函数声明为èxtern "C"

Answer 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;
}

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

Android NDK：找不到本机xxxxxx的实现

2 个答案: