Question

I have a java project and now I want to add some NDK functionality.

here is my Android.mk:

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE    := android
LOCAL_CFLAGS    := -Wno-psabi
LOCAL_SRC_FILES := android.c
LOCAL_LDLIBS    := -L$(SYSROOT)/usr/lib -llog

include $(BUILD_SHARED_LIBRARY)

here is my android.c

#include <jni.h>  
#include <string.h>  
#include <android/log.h>  

#define DEBUG_TAG "NDK_AndroidNDK1SampleActivity"  

void Java_ru_tonybo_app_NativeRenderer_print(JNIEnv* env, jobject thiz, jstring message) {
    jboolean isCopy;  
    const char * szMessage = (*env)->GetStringUTFChars(env, message, &isCopy);

    __android_log_print(ANDROID_LOG_DEBUG, DEBUG_TAG, "NDK:LC: [%s]", szMessage);

    (*env)->ReleaseStringUTFChars(env, message, szMessage);
}

here is my related java class

package ru.tonybo.app;

public class NativeRenderer {
    public NativeRenderer (String message) {
        print(message);
    }

    public native void print(String message);

    static {
        System.loadLibrary("android");
    }
}

NDK compilation through cygwin is ok

TonyBo@TonyBo-NoteBook /cygdrive/d/javaProjects/App_JNI/jni
$ /cygdrive/d/android-ndk-r8b/ndk-build -B
Cygwin         : Generating dependency file converter script
Compile thumb  : android <= android.c
SharedLibrary  : libandroid.so
Install        : libandroid.so => libs/armeabi/libandroid.so

libandroid.so is created and placed in /libs/armeabi/libandroid.so

but when I launch the application in eclipse on the device, I got the exception UnsatisfiedLinkError on native call print(message);

What I’m missing here or doing wrong?
May be I should somehow tell eclipse to look for shared libraries, if so how to do this?

Answer 1

Your choice of libandroid name is not a good idea. The library libandroid.so exists in the system folder /system/lib. It is loaded into your app, and therefore your Load() call simply returns. If you change the name of your native library, everything will be well.