I am exploring Android platform source code. I'd like to understand how parts of the platform are implemented. I am looking for a way to leverage Eclipse's java development tools and C/C++ development tools to explore the code efficiently. I need a way for Eclipse to find related code in different sub-modules. For example I'd like to have "show declaration" facility (ctrl+mouse click) that will take to source code located in different directory/module.
I need to be able to explore Java and C/C++ platform code in same Eclipse window.
I don't dream about Java to JNI C++ code traversal, just inside same language (Java-to-Java and C++-to-C++). I also don't dream about traversal from C library code to kernel code.
Are you aware of a way to make Eclipse import every sub-module of Android platform as separate project while retaining dependencies/includes, or any other way to make code browsing easy?
I have stumbled upon some commercial Eclipse distribution that does it (don't remember it name), but nothing free/flexible.
You may install CDT and create project for native part needed or as whole. But it is not as good as source insight for c/c++ parts.
Related
JSI is about to become quite popular in native module development but there's still very little information on how to get started with it.
One of the things I'm wasting more of my time on is setting up an IDE to get IntelliSense / code completion with the c++ side of things.
I have both CLion and Android studio and i couldn't figure out a way to make it work at all. Android studio seems to just ignore the CMakeLists.txt file inside the android/ folder. On clion when loading the CMakeLists.txt file it just can't find half the variables and paths needed and if i manually set the variables via the settings it keeps giving errors on errors.
I'm pretty new to c++ development but i managed to setup a few c++ projects so far, but i have no idea how to do this for RN.
Basically, you need two IDEs, one for react-native's codes, and one for C++ code.
In my experience, Qt Creator IDE had best support for CMakeLists.txt as project, but give newer MSVC versions a try (they added support recently).
Also, VS Code was good for react-native.
But if you don't write much C++ code, simply use VS Code for both.
I have coded a library that provides some function add, sub, divide, multi by c/c++ programming language. It's built to library.so by using Android NDK. So now, I want to call these function of library by using Android. I want to as How I can do ?
Thank.
For a working example project, you can find one from here: https://github.com/russell-shizhen/JniExample
NDK Package
Android Studio only includes the default tools and SDK, so download and install the NDK package separately. There are two ways to do this. The first and easiest is the automatic installation option in the SDK Tools tab. This is a large download (~1GB) so be sure to have a good internet connection and/or patience.
The second way is to download the NDK manually from the NDK Downloads page. This saves some time because of the smaller download size (<.5 GB) but will need some setting up. Download the appropriate NDK package for your platform and follow the installation instructions. You can put the extracted package anywhere you want, but remember this location as you will need it later.
Hello World
Let’s run a test project to see if the NDK installation works. The NDK package folder contains samples but they don’t seem to work out of the box in Android Studio without extra configuration. Instead we’ll import samples that work from the welcome screen. These NDK samples from GitHub can also be downloaded or cloned directly. This collection of samples has better compatibility with the latest version of Android Studio.
Select Import an Android code sample and type hello in the search box to filter the list. Choose Hello JNI from the filtered list under the Ndk category. Click Next to edit the app name and project location, then click Finish.
JNI
After the code has loaded and Gradle has synced, let’s take a look at the resulting project structure. You might have noticed what appears to be a discrepancy in the project’s name. Why is it called HelloJNI and not HelloNDK? What is ‘JNI’ and how does it differ from the ‘NDK’? The ‘Java Native Interface’ is a framework that enables Java applications to interact with native code. The JNI and the NDK work together to bring native support to Android apps. The NDK is part of the Android framework while the JNI is available to any Java application, not just Android apps.
Inside the project is a folder named jni which will hold all the native C or C++ source code of the app. The JNI provides a two-way interface. The C/C++ code is able to call Java code, including the standard Android libraries, and the Java code is able to call native functions defined in C/C++ code. Native code is governed by the same sandbox and security rules as Java code so the app will not have full unrestricted access to hardware. For a more detailed discussion on the JNI, read the JNI articles from the Android Developer website.
I am building C libraries that will be used by an android app(through either JNI or the NDK, I've never used the NDK though) and I am wondering what IDE/development environment is best to use? I've basically only used Visual Studio for native development and I'm not sure how to adapt to building .so libraries for use on android.
Thanks
EDIT: Update -- I want to avoid makefiles if possible (never used them) and rather use a complete IDE such as the case with visual stuido to compile
Generally, cygwin (i.e. command line) is used for building Android native code. But you can also try to use Eclipse for this purpose. It doesn't help very much but it highlights syntax and you don't have to switch to other apps to write code and build your app. You can read more about using Eclipse for C/C++ Android development here.
I would strongly recommend that you use the NDK's compiler.
Normally this is done by writing an Android.mk in accordance with the instructions for the NDK. It is not complicated. The easiest thing to do is to grab the hello-jni sample app and just make the necessary changes, for example substituting your source files into its android.mk.
You can stay in visual studio if you like that as an editing environment, simply using the ability to bind an external command to a keystroke to launch the ndk build script. Ages ago I had figured out how to reformat GCC error messages with sed into something that VS could parse to make them click-able, though I soon moved development of that project under linux.
I think a lot of people use Eclipse as their IDE for Android development. I use it and its pretty good. You shouldn't have any problems if you're used to VS.
The Android SDK comes with a plugin, the Android Development Tools (ADT), to develop applications for Android inside the Eclipse IDE, which is same kind of beast as Visual Studio. And within that IDE, it is possible to use JavaCPP (disclaimer: I am the author) to have it compile all the native C/C++ stuff we need through the Android NDK, but without needing Makefiles and such. More details here:
http://code.google.com/p/javacpp/#Instructions_for_Android
I'd like to build some native libraries for android using the NDK (native development kit), but i'd like to use Visual Studio 2010 to do it. I've googled quite a bit but haven't found any information on it. Does anyone have any experience with this and know the steps necessary to make this happen? I have CYGWin installed, made sure i get Make (per the NDK instructions), but i'm not really sure of the next steps in terms of setting up the project, compiler in visual studio, etc.
If anyone knows of any write-ups, tutorials, or links to sample projects, that would be awesome, as there isn't much on google yet.
thanks!
Here's another solution, which integrates the NDK fully within Visual Studio. No makefiles. It behaves like a proper Win32 project:
Here's an excellent blog post about how you can configure your environment to debug android NDK code using Visual Studio.
Visual Studio is officially not supported.
Some problems (but not limited to):
MSVS cannot create the proper ARM binaries
Android makefiles (.mk) are not supported by MSVS
There are however, third party solutions:
vs-android
VisualGDB
You might want to check out DS-5 as well, though it's not Visual Studio.
The answer depends on what kind of integration you require.
To just build the native Android code from Visual Studio you can create a new Makefile project, and make it run ndk-build.cmd when you press "build". If you would like to get the error messages mapped as well, you will need to parse the output of ndk-build.cmd and convert it to a format that Visual Studio can udnerstand.
If you want to debug your native Android code from Visual Studio, you will need a third party tool that will control ndk-gdb on behalf of Visual Studio and provide workarounds for several bugs (e.g. rebind breakpoints when libraries are loaded).
You can try our VisualGDB for Android tool that does exactly that - creates projects that wrap ndk-build and controls NDK debugger on behalf of Visual Studio. If you need more information, there is a step-by-step tutorial available.
I have not found a direct clean solution, here is my workaround.
I develop my native code on VS as a static library, and use some test project to try it as a console aplication.
When it is ok, from cygwin I use a little bash script that copies all needed files to the jni folder and launch the standard android ndk make command. (also copy some file to assets folder when needed), producing the executable in the right folder.
To use the pthreads I have linked my projects to pthreads-win32.
The only files I do not compile in VS are the jni code.
I hope this can help you.
There's also a couple of other third party alternatives for developing ANdroid apps with VS in addition to those above. There is the open source dot42 located at http://www.dot42.com and Remobjects, http://www.remobjects.com , which allows you to program in c#, Pascal, and Swift. I have played with the trial of Remobjects and am now starting to play around with dot42.
My use of the remobjects trial allowed me to recreate in c# the first five chapter projects in the textbook of the Android course I took. I haven't had the same success with dot42 so far but I need to find some time to really give it a chance.
I've been running the Android SDK for a while now in Eclipse (MAC OSX). I've downloaded the NDK and installed the C/C++ tools in Eclipse, but could anyone guide me on using the NDK? For example, do I just create an Android project like normal and build it with the NDK instead?
Really could do with a decent tutorial if anyone know of any.
EDIT: OK so I have the NDK installed now (I think) but does anyone have any idea how to use it? I got as far as this (taken from here):
Run Terminal
cd ~/android-ndk-1.5_r1
make APP=hello-jni
In order to run the hello-jni sample application, but I get an error in terminal saying:
Android NDK: APP variable defined to
unknown applications: hellojni
Android NDK: You might want to use
one of the following:
build/core/main.mk:81: *** Android
NDK: Aborting . Stop.
Any ideas why?
As simply as I can describe it, building an Android app from within Eclipse that uses the NDK requires two steps.
First, inside your terminal you need to run the NDK build script on your project. cd into the root of your project directory and then execute the ndk-build script within that directory.
For example:
cd ~/workspace/hello-jni
./~/android-ndk-1.5_r1/ndk-build
After doing this, you should see some output that results in the creation of a *.SO file within the obj directory within your project directory.
Once you have the *.SO file, the final step to building an application with the Android NDK through Eclipse is to build it with Eclipse like you would any other application and then deploy it for testing.
If you make any changes to the C/C++ code you'll need to repeat step one and regenerate your *.SO file before building and deploying your application from within Eclipse again.
I would like to note that by using the Android NDK your android apps are still based upon Java. They're just communicating with code written in C/C++ by way of the Java Native Interface.
Finally, I am not aware of any Eclipse plugins that will aid with NDK development. Everything I know about the NDK I have learned the official Android NDK documentation. Please feel free to comment and let me know if there anything I can clear up in my response.
Native development and debugging support came into Eclipse environment as of ADT version 20. http://tools.android.com/recent/usingthendkplugin
Set path to NDK from Eclipse Preferences -> Android -> NDK
Right-click on your project and choose Android Tools -> Add Native Support
developer.android.com states you also need Cygwin.
http://developer.android.com/tools/sdk/ndk/index.html#Contents
Required development tools
For all development platforms, GNU Make 3.81 or later is required. Earlier versions of GNU Make might work but have not been tested.
A recent version of awk (either GNU Awk or Nawk) is also required.
For Windows, Cygwin 1.7 or higher is required. The NDK will not work with Cygwin 1.5 installations.
The docs directory in the NDK has some pretty good information on how to use the NDK itself. Read the overview, Application.mk, and Android.mk HTML docs. You'll want to google for the Sun JNI PDF, download it, and learn what JNI is all about before you go any further. This is because simply compiling a bunch of C/C++ code into libraries with the NDK is only part of the process. You have to write native Java code that calls your C/C++, and you have to create wrapper functions in C/C++ that adhere to JNI conventions that the native Java code can invoke. JNI has been around a long time, it's not Android specific by any means. So, you can, to learn about it, go quite far following tutorials geared towards JNI, using command line tools like javah and javac, and then return to integrating with the NDK after you know the basics. (For an example of what these C shims look like, take a look at the hello-jni sample in the NDK; the C source file there shows you typically what the shims look like. Using javah to generate these shims is the way to go, you create Java classes that have native methods, process them with javah, and it generates the C headers for you, then you code up C functions that adhere to the generated function prototypes).
Note: while the NDK docs would have you manually building from command line and then going into Eclipse to build your app (a laborious sequence of steps, to be sure, especially if you are changing the C/C++ code), it turns out you can integrate easily with Eclipse so that the NDK is run each time you build from Eclipse. To see how, read here.
This is for benefit of others who want to create the project from scratch from within eclipse: I followed steps mentioned here in this blog here and it works fine: http://mhandroid.wordpress.com/2011/01/23/using-eclipse-for-android-cc-development/
To attempt to answer the question directly - you need to run ndk-build in the folder with the native code within your project folder. This creates the .so files found in the file explorer/resources tree under jni in Eclipse. These functions, if the syntax in the code is correct, can now be called from your java code.
I found many sources of help when install and getting to grips with Android Developer Tools and the NDK. I wrote a blog post to share my experiences and hopefully give back to the community that helped me get there which may help understand my answer: http://workingmatt.blogspot.co.uk/2013/03/set-up-android-sdk-and-ndk.html