I am trying to connect Unity with simple Java android development and I actually succeeded to get to the part where I can import unity project to android and if needed start it up.
The problem I am facing at the moment is how to pass variables back and forth between those 2 platforms. I found some tutorials and they all suggest to use Android NDK. I am new in this field and got some problems while getting it to work.
I followed this tutorial and got stuck on building the application. I have my Android.mk file but when I run make (make app=ndk-demo) it throws an exception:
"make: *** No targets specified and no makefile found. Stop."
My Android.mk file looks like:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := ndk-demo
LOCAL_SRC_FILES := $(call all-subdir-java-files)
include $(BUILD_SHARED_LIBRARY)
I have 3 activities in my project, one .h and one .c files. I don't know whether I should include them or all-subdir-java-files does it for me.
In the answer to this question I've described step-by-step instructions how to make a native project. Hope this help you.
Related
I am new to Android development and I have no idea how to include the library that comes with the Google Tango SDK.
The app, as it is, is a small java wrapper around a c++ core that is basically a lightweight render engine. It can render one model and handle input. It is all done in C++ using Android NDK.
The problem is that I now want to use functions like onXyzIjAvailable(). How do I include and use the library? I know of this, but I need to include the library and get access to the TangoService_connectOnXYZijAvailable() function.
I want to stress that I am new to android development and I have never included anything. I have only written the code myself or used Android Studio to download and include the SDKs, generate the GRADLE files and take care of the compilation/makefles. I found this SO post talking about adding a library, but I did not understand the answer. How do I import it to this project and build it?
Thank you so much for the help.
You must download the current tango api and service sdk for C here
Unzip and place the folders (I named them tango_client_api and tango_service_sdk) you want to. I prefer a structure like that:
ProjectFolder/app/
ProjectFolder/build/...
...
tango_client_api/
tango_service_sdk/
third-party/...
...
Now you have to include the lib paths into your Android.mk makefile (located in path like ProjectFolder/app/src/main/jni/Android.mk) as followed:
LOCAL_PATH := $(call my-dir)
PROJECT_ROOT_FROM_JNI:= ../../../../..
PROJECT_ROOT:= $(call my-dir)/../../../../..
include $(CLEAR_VARS)
LOCAL_MODULE := lib_your_project_name
LOCAL_SHARED_LIBRARIES := tango_client_api
LOCAL_CFLAGS := -std=c++11
LOCAL_C_INCLUDES := $(PROJECT_ROOT)/tango_service_sdk/include/ \
LOCAL_SRC_FILES := your-project-file1.cc \
your-project-file2.cc \
your-project-file3.cc
LOCAL_LDLIBS := -llog -lGLESv2 -L$(SYSROOT)/usr/lib
include $(BUILD_SHARED_LIBRARY)
$(call import-add-path, $(PROJECT_ROOT))
$(call import-module,tango_client_api)
In your .h files you can use for example: #include <tango_client_api.h>
to get access to all TangoService_functions
And that's it. I really recommend you to look into the tango C examples on github https://github.com/googlesamples/tango-examples-c
I want to use libcurl in my native project. How can I integrate this library and build using ndk? Is there any post available that can guide me through the process?
I tried the docs from official site, but that's not working. FYI I am on windows platform.
Create a JNI folder within your project and add a folder for each architecture(arm, armv7,x86 etc). Place the corresponding libcurl.so files in the respective folders. Since this is a rebuilt shared binary you need to add this to your Android.mk file
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := <Curl> //add the module name here.
LOCAL_SRC_FILES := <libCurl.so> //add the .so file name here
LOCAL_C_INCLUDES := $(LOCAL_PATH)/../jni/include
include $(PREBUILT_SHARED_LIBRARY)
Create a JNI C file that uses the libraries from Curl and call the native code from Java source.
static {
System.loadLibrary("curl");
}
It shouldnt make a difference if you are on Windows platform. Adding open source liv files to Android NDK is pretty much the same process on all platforms.
No idea about windows, but as to the linker magic, see the links in
Integrating MuPDF as a library project (Android)
I'm trying out NDK for the first time, and I'm stuck with building this project. I'm attempting to use the libraries used in Android's screencap recording program to read data from my screen. I understand that I need to use LibGUI, which I've pulled from my phone. Whenever I compile, however, I get this as an error message:
C:/Users/Kevin/Desktop/ScreenCapture//jni/main.cpp:2:34: fatal error: gui/ISurfaceComposer.h: No such file or directory
Which is odd, considering that I have libgui.so included.
What my main file looks like:
#include <stdio.h>
#include <gui/ISurfaceComposer.h>
int main() {
printf("Started!");
return 0;
}
What my Android.mk looks like:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := libgui-prebuilt
LOCAL_SRC_FILES := libgui.so
include $(PREBUILT_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := screencapture
LOCAL_SRC_FILES := main.cpp
LOCAL_SHARED_LIBRARIES := libgui-prebuilt
include $(BUILD_EXECUTABLE)
And I have both the main file and libgui.so in the same folder.
main.cpp:2:34: fatal error: gui/ISurfaceComposer.h: No such file or directory
Your error message indicates that the compiler is unable to find a header file, but your attempted solution is to provide a shared object (.so) library from the phone.
Libraries might help at link time, but before you can link you must successfully compile, and to do that you are going to have to obtain the missing header (perhaps from AOSP sources, as source code it will not be found on the phone) or else recreate it by deducing its contents from clues you collect. Unfortunately, it often isn't possible to take just one internal header out of AOSP, as it will likely depend on many others.
Linking against private system internals also introduces a risk of your program breaking if the private interface between internal components changes between Android versions.
(Normally I would also mention that you are unlikely to be able to record a screen with the NDK in it's normal usage of making a shared library to link into an application process, however your Android.mk seems to indicate you are building an executable - that might work if you can succesfully build it and you run it as a user with sufficient permission such as adb's shell userid or using a root hack)
Add one line for module screencapture:
LOCAL_C_INCLUDES := $(LOCAL_PATH)/
If you haven't folder gui, you need to copy&paste includes headers *.h into folder jni/gui. Always such a requirement about using like that for ndk...
Or second case - using other location of this source for ldlibs:
LOCAL_LDLIBS := -L/full_path_to_source_gui/gui/
I'm currently implementing a custom Logging mechanism that I need to be accessible from both native and Java code. The fundamentals of the logging are implemented in C/C++ with a Java wrapper, and the two together are being built as an android Library Project.
The issue at hand is that while my Java code can access the Library project output, there doesn't seem to be a way for my native code to access the native .so or headers from the Library project. Is there an additional step I'm missing or is this just a limitation of the current ADT? More specifically, is there a makefile/eclipse configuration that will address the things I'm used to getting out of Library projects in general? (Build .so as needed, import rebuilt .so, import relevant headers for c/c++ compilation, etc.)
I don't think it's a limitation. We are supposed to declare native code dependencies in Android.mk and Application.mk
Worked out a way to get what I wanted - most of the information is (of course) in the NDK documentation, but what I was trying to do isn't 100% supported within the ADT. It should also be noted that I'm currently stuck developing in a windows environment, so much of this might be easier or unnecessary in Linux. The first key is the $(call import-module ...) macro. Within your library project, move the source files and the Android.mk folder into a named directory you can locate later. My Library project directory looked like this:
MyProject
> src
> res
v jni
- Application.mk
v MyLib
- source.cpp
- source.h
- Android.mk
I also had to edit my Application.mk to point to the project:
APP_PROJECT_PATH := <path-to-my-project>
APP_BUILD_SCRIPT := $(APP_PROJECT_PATH)/jni/MyProject/Android.mk
Annoyingly, this broke my Android.mk in ways unforseen until I added a ./ to my source files. Also you need to export your includes for linking:
LOCAL_SRC_FILES := ./source.cpp
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)
Ensure that the system path variable NDK_MODULE_PATH is set to include your library's JNI directory, e.g. <path-to-my-project>/jni (Note: I had to restart eclipse after I did this).
In the receiving application's Android.mk file (the one you'd like to link natively to your app), import the module:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := MyNativeProject
LOCAL_SRC_FILES := source.cpp
LOCAL_CFLAGS := -DANDROID_NDK -g -std=c99
LOCAL_SHARED_LIBRARIES := MyLib
include $(BUILD_SHARED_LIBRARY)
$(call import-module,android/native_app_glue)
$(call import-module, IntelLog)
At this point everything built perfectly, but the APK packager didn't like the generated .so binary being included twice (once from the Library project's natural import process, and again from the import-module call). To solve this, clean the library and don't build it again! the import-module call will build the .so and import it into your project. (Obviously, if your project only requires the Java API, you would need that .so file to be built). Congratulations! you have a functional (if not straightforward) build process with a hybrid native/Java Library
I found a lot of tutorials showing how to start developing Android Applications using NDK.
But I have a rather "easy/stupid" question:
Please consider the following two tutorials:
http://mobile.tutsplus.com/tutorials/android/ndk-tutorial/
http://www.indiedb.com/tutorials/creating-compiling-and-deploying-native-projects-from-the-android-ndk
http://mindtherobot.com/blog/452/android-beginners-ndk-setup-step-by-step/
http://marakana.com/forums/android/examples/49.html
Now, in the second tutorial they are building the hello-jni example.
My question is:
After using the ndk-build
and producting the:
is it possible to use the resulted libhello-jni.so and distribute this to others instead of the actual C code?
For example modifying the Android.mk and replacing com_myproject_MyActivity.c to something.so in order to include the shared library?:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := mylib
LOCAL_SRC_FILES := com_myproject_MyActivity.c
include $(BUILD_SHARED_LIBRARY)
Any suggestions or tutorials welcome. Thanks in advance.
You can use a prebuilt NDK library by copying it into libs/armeabi (or whatever architecture is it for), then loading in run-time. From the standpoint of the Android build system, it's just another file to include in the APK.
The problem, however, is that the JNI function names include, by convention, the name of the package and class they will belong to; so from the standpoint of a SO consumer project, its use will look rather unnatural, as none of the JNI functions would fit into its classes. You'll probably have to ship a companion JAR where the respective Java classes are declared.
Via VitamioBundle,
You no need to do re-using code:
is it possible to use the resulted libhello-jni.so and distribute this to others instead of the actual C code? For example modifying the Android.mk and replacing com_myproject_MyActivity.c to something.so in order to include the shared library?
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := mylib
LOCAL_SRC_FILES := com_myproject_MyActivity.c
include $(BUILD_SHARED_LIBRARY)
VitamioBundle can be considered as shared library,
Therefore, you can use it as your Android Library.
Let's fun.