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UnsatisfiedLinkError problem

开发者 https://www.devze.com 2023-04-04 22:44 出处:网络
I\'m developing an Android application that uses JNI. The command javah -jni com.company.tests.MainRenderer gave me this output:

I'm developing an Android application that uses JNI.

The command javah -jni com.company.tests.MainRenderer gave me this output:

/*
 * Class:     com_company_tests_MainRenderer
 * Method:    nativeInit
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_com_company_tests_MainRenderer_nativeInit
  (JNIEnv *, jclass);

/*
 * Class:     com_company_tests_MainRenderer
 * Method:    nativeRender
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_com_company_tests_MainRenderer_nativeRender
  (JNIEnv *, jclass);

The command nm -Ca libRotateJNI.so gave me this output:

00001c25 T Java_com_company_tests_MainRenderer_nativeInit(_JNIEnv*, _jclass*)
00001c29 T Java_com_company_tests_MainRenderer_nativeRe开发者_如何学运维nder(_JNIEnv*, _jclass*)

This is how are defined these functions:

void Java_com_company_tests_MainRenderer_nativeInit( JNIEnv*  env, jobject thiz )
{
    // ...
}

void Java_com_company_tests_MainRenderer_nativeRender( JNIEnv*  env, jobject thiz )
{
    // ...
}

And running it with this message:

WARN/dalvikvm(639): No implementation found for native Lcom/company/tests/MainRenderer;.nativeInit ()V

I'm sure library is loaded. Do you know how can I fix this problem?


I suspect you compiled your native methods with a C++ compiler, and didn't give them extern "C" linkage. The -C option you're providing to nm demangles the C++ names, but in reality, the symbols have names different from what the JVM is looking for because the code was compiled with C++ linkage. Enclose your C++ code in an extern "C" block and this should clear things up.


I don't know what your MainRenderer is and what native library you are hitting but my c file functions always look something like this:

void Java_com_ndkfoo_NDKFooActivity_invokeNativeFunction(JNIEnv* env, jobject javaThis) {

The method/class I am calling is NDKFooActivity and its invoking a native Function...

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