Android NDK C++ JNI (no implementation found for native...)

user_255293 0
Viewed 106121

I'm trying to use the NDK with C++ and can't seem to get the method naming convention correct. my native method is as follows:

extern "C" {
JNIEXPORT void JNICALL Java_com_test_jnitest_SurfaceRenderer_drawFromJni
(JNIEnv* env, jclass c)
{
   //
}
}

with a header wrapped in extern "C" {} aslo.

Everything compiles fine, creates a .so file and copies to the libs folder under my project, but when I debug and run in Eclipse I keep getting a log cat message that of "no implementation found for native...". Is there something i'm missing as all the NDK examples are in C?

Thanks.

android-ndk android
11 Answers

There are a couple of things that can lead to "no implementation found". One is getting the function prototype name wrong, another is failing to load the .so at all. Are you sure that System.loadLibrary() is being called before the method is used?

If you don't have a JNI_OnLoad function defined, you may want to create one and have it spit out a log message just to verify that the lib is getting pulled in successfully.

You already dodged the most common problem -- forgetting to use extern "C" -- so it's either the above or some slight misspelling. What does the Java declaration look like?

user_2942480
user_2667150

I Faced the same problem, and in my case the reason was that I had underscore in package name "RFID_Test" I renamed the Package and it worked. Thanks user1222021

user_20340090

I faced the same problem twice. It happened, that the phone I tried to start the app from Android Studio used an API level that I haven't downloaded yet in Android Studio.

  1. Upgrade Android Studio to the latest version
  2. Download the necessary API from within Android Studio
user_90939670
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