Question

Im trying to use libspotify for an android app but Im having some problems building my c wrapper. Ive created a very small wrapper that only asks libspotify what its version is.

My folder structure looks like this:

jni
 |-libs
 |  |-Android.mk
 |  |-libspotify.so    (symlink)
 |  |-libspotify.so.12 (symlink)
 |  |-libspotify.so.12.1.51
 |
 |-include
 |  |-libspotify
 |     |-api.h
 |
 |-Android.mk
 |-spotifywrap.c

/jni/Android.mk

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)
LOCAL_SHARED_LIBRARIES := libspotify
LOCAL_MODULE := spotifywrap
LOCAL_SRC_FILES := spotifywrap.c
LOCAL_C_INCLUDES := $(LOCAL_PATH)/include
include $(BUILD_SHARED_LIBRARY)

/jni/spotifywrap.c

include <jni.h>
include <libspotify/api.h>

jstring Java_com_example_ndktest_MainActivity_getBuild(JNIEnv * env, jobject this)
{
    jstring result = (*env)->NewStringUTF( env, sp_build_id() );
    return result;
}

/jni/libs/Android.mk

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)
LOCAL_MODULE := libspotify
LOCAL_SRC_FILES := libspotify.so
include $(PREBUILT_SHARED_LIBRARY)

When I run ndk-build I get this:

spotifywrap.c:6: undefined reference to `sp_build_id'

sp_build_id is part of the interface in api.h.

Any ideas on what Im doing wrong?

Answer 1

I have a feeling that your directory structure within the jni subdirectory is what’s causing you problems. Try editing your Android.mk build file to add this:

LOCAL_CPPFLAGS = -std=c++0x -D__STDC_INT64__
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include

Also, I have a feeling that you’ll need to copy libspotify.so to your top-level libs/armeabi directory to link successfully.