Android NDK/JNI: Building a shared library that depends on other shared libraries

Question

I am writing an android app that wants to make JNI calls into a shared library built in using the NDK. The trick is this shared library calls functions provided by OTHER shared

Answer 1

Your problem is with the naming convention. NDK and Android insist on the shared library names to always begin with lib. Otherwise, the libraries will not be linked properly, and not copied to the libs/armeabi folder properly, and not installed on the device (copied to /data/data/package/lib directory properly.

If you rename support_lib1.so to libsupport_1.so and support_lib2.so to libsupport_2.so, and put these two files in jni/lib directory, then your Attempt #5 will work with minor change:

LOCAL_PATH := $(call my-dir)

#get support_lib1
include $(CLEAR_VARS)
LOCAL_MODULE           := support_lib1
LOCAL_SRC_FILES        := lib/libsupport_1.so
include $(PREBUILT_SHARED_LIBRARY)

#get support_lib2
include $(CLEAR_VARS)
LOCAL_MODULE           := support_lib2
LOCAL_SRC_FILES        := lib/libsupport_2.so
include $(PREBUILT_SHARED_LIBRARY)

#build native lib
include $(CLEAR_VARS)    
LOCAL_MODULE           := native_lib
LOCAL_SRC_FILES        := native_lib.cpp

LOCAL_LDLIBS := -L$(SYSROOT)/../usr/lib -llog
LOCAL_SHARED_LIBRARIES := support_lib1 support_lib2

include $(BUILD_SHARED_LIBRARY)

BTW, I don't think you need this -L$(SYSROOT)/../usr/lib.

PS Don't forget to update the Java side, too:

static {
    System.loadLibrary("support_lib1");
    System.loadLibrary("support_lib2");
    System.loadLibrary("native_lib");
}