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How to add static c-library (libsrtp) to Android-Project using NDK

so I'm relatively new to Android-NDK and trying to add an uncompiled c-library to android.
I've downloaded the library's source from here and followed these instructions to create a static library (.a-File) from the downloaded files using ndk-build.
So now I have a folder-structure that looks like this:
-srtp
--include (srtp.h, crypto.h)
--srtp (srtp.c...)
--obj
---local
----armeabi
-----libsrtp_static.a
In my Android-project I want to include srtp.h in a c-file inside my /jni/ folder. I've tried to just add the .a-file to the /jni folder but than it says "srtp.h no such file or direcotry". If I add the entire srtp-folder to the project and include the header with "srtp/include/srtp.h" it compiles but fails to link the source as I get the error "Undefined reference to srtp-function-call"
Here's my Android.mk (parts of it copied from Android.mk within the downloaded source):
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_LDLIBS := -llog
LOCAL_MODULE := ndk1 #name of my project
LOCAL_SRC_FILES := native.c #name of the c-source file
include $(BUILD_SHARED_LIBRARY)
LOCAL_PATH:= /home/dev/programing/srtp
common_SRC_FILES := \
srtp/srtp.c \
srtp/ekt.c \
crypto/cipher/cipher.c \
#...more files like that
common_CFLAGS := \
-DPOSIX -iquote$(LOCAL_PATH)/crypto/include \
-Werror \
-Wno-ignored-qualifiers \
-Wno-sign-compare \
-Wno-missing-field-initializers
common_C_INCLUDES = $(LOCAL_PATH)/include
# For the device
# =====================================================
# Device static library
include $(CLEAR_VARS)
ifneq ($(TARGET_ARCH),x86)
LOCAL_NDK_VERSION := 5
LOCAL_SDK_VERSION := 9
endif
LOCAL_SRC_FILES := libsrtp_static.a
LOCAL_CFLAGS += $(common_CFLAGS)
LOCAL_C_INCLUDES += /home/dev/programing/srtp/include
LOCAL_MODULE:= libsrtp_static
LOCAL_MODULE_TAGS := optional
include $(BUILD_STATIC_LIBRARY)
Any help is greatly appreciated! Thank you very much.

You need to add the reference to libsrtp_static from your lib (ndk1) declaration :
LOCAL_STATIC_LIBRARIES := libsrtp_static
Also, you don't need to copy all the strp sources to your project, only add this to your static prebuilt library definition
LOCAL_EXPORT_C_INCLUDES += /home/dev/programing/srtp/include
This path will then be automatically added to the LOCAL_C_INCLUDES of your library that is using the library.
Are you building libsrtp or just using a prebuilt static library ? If you're using a prebuilt (lib*.a), replace BUILD_STATIC_LIBRARY with PREBUILT_STATIC_LIBRARY and set only the .a as SRC_FILE:
In summary, once libstrp_static.a is built, this should work:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_LDLIBS := -llog
LOCAL_MODULE := ndk1 #name of my project
LOCAL_SRC_FILES := native.c #name of the c-source file
LOCAL_STATIC_LIBRARIES := libsrtp_static
include $(BUILD_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_SRC_FILES := /home/dev/programing/srtp/libsrtp_static.a #check path to libsrtp_static.a
LOCAL_EXPORT_C_INCLUDES += /home/dev/programing/srtp/include
LOCAL_MODULE:= libsrtp_static
LOCAL_MODULE_TAGS := optional
include $(BUILD_STATIC_LIBRARY)

How to link .so file in android

I have two projects. The output of first one is libtest.so file. Using this shared object file in the 2nd project, i want to generate final android executable, AndroidExe.
I generated libtest.so and its Android.mk is given below
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_CFLAGS := -g
LOCAL_ARM_MODE := arm
LOCAL_MODULE :=test
LOCAL_SRC_FILES := test.c
export LD_LIBRARY_PATH=/data/local/tmp
include $(BUILD_SHARED_LIBRARY)
Here the problem i am facing is that, i don't know how to link this .so file in my final executable project. In this final project, i am using one of the function (sum(a,b)) defined in the .so lib.While do build, showing error undefined reference to 'sum'.Its Android.mk file is given below:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_CFLAGS := -g
LOCAL_ARM_MODE := arm
LOCAL_MODULE :=AndroidExe
LOCAL_SHARED_LIBRARIES := libtest.so
LOCAL_SRC_FILES := AndroidExe.c
include $(BUILD_EXECUTABLE)

just check ndk documentation and try some of the samples.

Prebuild of static library failed

I try to set up an Android NDK build based on CMake scripts, which dynamically create the required Android make files. While I can't use the JNI folder structure I split the build process in several separated make scripts:
1st Create root Android.mk file located in project root:
#ANDROID ROOT MAKEFILE
LOCAL_PATH := D:/binrev/repository/bar
include $(CLEAR_VARS)
MY_LOCAL_CFLAGS := -DDEBUG
include D:/binrev/repository/bar/src/Android.mk
2nd Create source Android.mk file in project source folder and perform module build:
$(info "[INFO] Source Makefile invoked")
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := bar
LOCAL_C_INCLUDES:= D:/binrev/repository/bar/include
LOCAL_SRC_FILES := bar.cpp
ifeq (debug,"debug")
MY_LOCAL_CFLAGS := -DDEBUG
endif
ifeq (false,true)
LOCAL_ARM_MODE := arm
endif
LOCAL_EXPORT_C_INCLUDES := D:/binrev/repository/bar/include
LOCAL_LDLIBS := -llog
LOCAL_LDLIBS += -landroid
LOCAL_STATIC_LIBRARIES += foo
ifeq (OFF, ON)
include $(BUILD_SHARED_LIBRARY)
else
include $(BUILD_STATIC_LIBRARY)
endif
Basicly this mechanism works and I could compile my sources, but I fail if I try to include a Prebuild of a library. I tried the following ways to include a pre-build
of a static library (with modified source/include definitions):
include $(CLEAR_VARS)
LOCAL_MODULE := foo
LOCAL_SRC_FILES := lib/android/$(TARGET_ARCH_ABI)/libfoo.a
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include
include $(PREBUILT_STATIC_LIBRARY)
1st Prebuild definition in source Android.mk file
2nd Call import-module mechanism and add Prebuild Android.mk file to prebuild-lib
3rd Prebuild definition in root Android.mk file
[Edit:] Here is the snipped of the call-import test which also fail:
$(info "[INFO] Source Makefile invoked")
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := bar
LOCAL_C_INCLUDES:= D:/binrev/repository/bar/include
LOCAL_SRC_FILES := bar.cpp
ifeq (debug,"debug")
MY_LOCAL_CFLAGS := -DDEBUG
endif
ifeq (false,true)
LOCAL_ARM_MODE := arm
endif
LOCAL_EXPORT_C_INCLUDES := D:/binrev/repository/bar/include
LOCAL_LDLIBS := -llog
LOCAL_LDLIBS += -landroid
LOCAL_STATIC_LIBRARIES += foo
ifeq (ON, ON)
include $(BUILD_SHARED_LIBRARY)
else
include $(BUILD_STATIC_LIBRARY)
endif
$(call import-module, external-deps/foo)
In each case the Script with the prebuild-definition is invoked, but the prebuild
is not performed. When my NDK build has been compleded, the prebuild library and
objects are not copied to my obj folder. It seems to me that the prebuild is
completely ignored. But the path to prebuild sources are correct, otherwise the
compile fails with missing file error.
You could get the complete source of this test implementation here:
[Test projects][1]https://sourceforge.net/projects/binrevengine/files/publications/
Hint: The bar project is the project which tries to prebuild the foo project.
The foo project contains the prebuild sources.
The added tests projects could be build by your own using MinGW64 with GCC 4.7/4.8 in handshake with CMake and pre installed NDK (using r8e).
I completly get lost and running out of ideas ...
Thanks for any help.

The Android build system will not build a static library without it being used by a shared library. Just create a dummy shared library that has your static library as a dependency and voila:
include $(CLEAR_VARS)
LOCAL_MODULE := dummy
LOCAL_PATH := $(LOCAL_PATH)
LOCAL_SRC_FILES := dummy.c
LOCAL_STATIC_LIBRARIES := foo
include $(BUILD_SHARED_LIBRARY)

To exclude possible sources of defects I've reduced the Android make file to simplest case without using CMake generator of those files:
LOCAL_PATH := D:/binrev/repository/bar
include $(CLEAR_VARS)
LOCAL_MODULE := foo-prebuilt
LOCAL_SRC_FILES := external-deps/foo/lib/android/$(TARGET_ARCH_ABI)/libfoo.a
include $(PREBUILT_STATIC_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := bar
LOCAL_C_INCLUDES:= D:/binrev/repository/bar/include
LOCAL_C_INCLUDES+= D:/binrev/repository/bar/external-deps/foo/include
LOCAL_SRC_FILES := src/bar.cpp
LOCAL_LDLIBS := -llog
LOCAL_LDLIBS += -landroid
LOCAL_SHARED_LIBRARIES := foo-prebuilt
include $(BUILD_SHARED_LIBRARY)
and:
LOCAL_PATH := D:/binrev/repository/foo
include $(CLEAR_VARS)
LOCAL_MODULE := foo
LOCAL_C_INCLUDES:= D:/binrev/repository/foo/include
LOCAL_SRC_FILES := src/foo.cpp
LOCAL_LDLIBS := -llog
LOCAL_LDLIBS += -landroid
include $(BUILD_STATIC_LIBRARY)
The failure still exists. The prebuild of the foo library is not executed. I also excluded MinGW64 as possible source of defect, if I try to build the project with Windows command line it results in same issue. The shared library is build, but the prebuild is not executed.
I checked my sources and scripts multiple times, but can't find any failure.
Any ideas what could be wrong or missing?

ADT tool chain not producing output for static libraries

Trying to build a static NDK library using Android's ADT Eclipse tool chain. However, whenever I build with BUILD_STATIC_LIBRARY, no output is produced: I get the message
make: Nothing to be done for `all'."
Any recommendations?
LOCAL_PATH := $(call my-dir)
STL_PATH := "C:/Android/ndk/sources/cxx-stl/gnu-libstdc++/4.6/include"
PLATFORM_INCLUDE := "C:/Android/ndk/sources/cxx-stl/gnu-libstdc++/4.6/libs/armeabi/include"
APP_STL := gnustl_static
include $(CLEAR_VARS)
LOCAL_MODULE := libCore
LOCAL_CPPFLAGS += -std=c++11 -fexceptions -D_OS_ANDROID
LOCAL_LDLIBS := -lGLESv2 -lEGL -lstdc++
LOCAL_C_INCLUDES += $(LOCAL_PATH)/Headers
...
LOCAL_SRC_FILES += Source/Engine/Game.cpp
...
include $(BUILD_STATIC_LIBRARY)

Here is the content of Android.mk file of two-libs sample project from Android NDK.
LOCAL_PATH:= $(call my-dir)
# first lib, which will be built statically
#
include $(CLEAR_VARS)
LOCAL_MODULE := libtwolib-first
LOCAL_SRC_FILES := first.c
include $(BUILD_STATIC_LIBRARY)
# second lib, which will depend on and include the first one
#
include $(CLEAR_VARS)
LOCAL_MODULE := libtwolib-second
LOCAL_SRC_FILES := second.c
LOCAL_STATIC_LIBRARIES := libtwolib-first
include $(BUILD_SHARED_LIBRARY)
You may try building the static library as part of another shared library as shown in the example.
I just did a ndk-build on the two-libs sample project and i could see the .a file along with .so in obj\local\armeabi directory.
Edit:
By default, ndk-build will only build shared libraries and executables, and the modules they depend on. To force a build specify libCore in APP_MODULES as follows.
APP_MODULES := libCore
or in command line as
ndk-build APP_MODULES=libCore

Error in linking C++ static library with android ndk(Error: file format not recognized)

I am trying to include static cpp library in android. This library is already compiled(on mac os) and i have its include files.
Here is my Android.mk file
LOCAL_PATH := $(call my-dir)
include $(call all-subdir-makefiles)
include $(CLEAR_VARS)
LOCAL_MODULE:= utils
LOCAL_SRC_FILES:= libUtils.a
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/utils
include $(PREBUILT_STATIC_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := sample
LOCAL_SRC_FILES := sample_cpp.cpp
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)
LOCAL_STATIC_LIBRARIES := utils
LOCAL_LDLIBS := -llog
include $(BUILD_SHARED_LIBRARY)
and here is Application.mk file
APP_STL := stlport_static
APP_CPPFLAGS = -fexceptions
but whenever it try to compile it using NDK i get the error
(Path of file)/libUtils.a: file not recognized: File format not recognized
collect2: ld returned 1 exit status

From the comments and so on it sounds like you trying to use a non arm version of the library. You should build the library with the ndk. The documentation has even documentation on how to do that.
For example building sigc++ could be like (from a project of mine, where sigc++ resides in the sigc++ subdirectory)
# SIGC++ Library built as static library
LOCAL_MODULE := sigc
LOCAL_PATH = $(CURRENT_DIR)
LOCAL_CPP_EXTENSION := .cc
LOCAL_SRC_FILES := sigc++/signal.cc sigc++/signal_base.cc sigc++/trackable.cc
LOCAL_SRC_FILES += sigc++/functors/slot_base.cc sigc++/adaptors/lambda/lambda.cc
LOCAL_SRC_FILES += sigc++/connection.cc sigc++/functors/slot.cc
LOCAL_C_INCLUDES := sigc++
include $(BUILD_STATIC_LIBRARY)
But you should really read how the compiling linking works. I am afraid building for android with ndk is more low level than using Xcode or Msvc.