NDK Introduction

The Android Native Development Kit (NDK)
NDK Info
What , Why , Why not ?
Requirement Tools & Installation of NDK
Developing an ADD application that uses the NDK

1. Android NDK Intoduction Rahul Tripathi

2. Agenda The Android Native Development Kit ( NDK ) NDK Info What , Why , Why not ? Requirement Tools & Installation of NDK Developing an ADD application that uses the NDK Final Output

3. NDK info Android Native Development Kit (Android NDK) Developer(s) - Google Initial release - June 2009; 5 years ago Stable release - 10d / December 2014; 2 months ago Written in- C and C++ Operating system- Cross-platform Available in- English Type- IDE, SDK Website- developer.android.com/tools/sdk/ndk/index.html

4. Native Development Kit What , Why ,Why Not? The NDK is a toolset that allows you to implement parts of your app using native-code languages such as C and C++. What is it? Build scripts/toolkit to incorporate native code in Android * apps via the Java Native Interface (JNI) Why use it? Performance e.g., complex algorithms, multimedia applications, games Why not use it? Performance improvement isn’t always guaranteed, in contrary to the added complexity

5. NDK Build Process 1. 3. 2. Dalvik Application Android NDK Application

6. What is JNI ? Android is put together of about equal part Java and C. we need an easy way to bridge between these two totally different worlds. Java offers Java Native Interface (JNI) as a framework connecting the world of Java to the native code.

7. NDK - System and Software Requirements The Android SDK A complete Android SDK installation (including all dependencies) is required. Android 1.5 SDK or later version is required. Supported operating systems Windows XP (32-bit) or Vista (32- or 64-bit) Mac OS X 10.4.8 or later (x86 only) Linux (32 or 64-bit; Ubuntu 8.04, or other Linux distributions) 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.

8. How to Install NDK On Linux and Mac OS X (Darwin): Download the appropriate package from this page. Open a terminal window. Go to the directory to which you downloaded the package. Run chmod a+x on the downloaded package. Execute the package. For example: ndk$ chmod a+x android-ndk-r10c-darwin-x86_64.bin ndk$ ./android-ndk-r10c-darwin-x86_64.bin The folder containing the NDK extracts itself. Note that you can also use a program like 7z to extract the package. On Windows: Download the appropriate package from this page. Navigate to the folder to which you downloaded the package. Double-click the downloaded file. The folder containing the NDK extracts itself.

9. Configure NDK Now Open Eclipse and Configure NDK . Go to window Option on the top. Click Preference : In Android ----> Select NDK ----> Give the path of your NDK Which you have Extracted by Terminal . (Note : Please Don't Make any Space in Contains Path Folder) You have to download For NDK .. Click Help : Install New Software ----> Select Release / Juno Link .. Now Select C/C++ GCC Cross Compiler Support C/C++ GDB Hardware Debugging Now Finish ....

10. Now Start With Project Create a Android Application Project --> Right Click on project --> Select Android tool --> Add Native Support -->

11. NDK Project Explorer in Eclipse Jni Folder C/C++ File Android.mk file Application.mk file After do that, your project has a folder called “jni” . Inside this folder, you have the Android.mk file, which goes your library configuration for the compiler. And there is a another file with .cpp (C++) extension, this is where your native code goes.You have to create A file in side jni folder Application.mk which describe which native 'modules' (i.e. static/shared libraries) are needed by your application.

12. Now Here is .Java , .MK

13. Android.MK & Application.MK Android.mk :- sub-makefile that describes the C++ static libraries and *.so files you want to build. Application.mk :- contains settings that apply to all the C/C++ code (processor type, API level, standard library, project-wide compiler options)

14. Calling Native From Java Create an activity .JAVA . Write A native method in side that Activity . JNI program uses a static initializer to load a shared library (" myjni.dll " in Windows or " libmyjni.so " in Ubuntu). It declares a native method. Code for your activity and usage of created .so file in your libs folder.

15. Create A JNI .h Header File Using "Javah" Generating C/C++ Header File using "javah" Utility Now We Have to Create Header File (.h) under JNI Folder . Using Terminal/Cygwin Go to your bin directory using cd command .. On Terminal/Cygwin . No..... You Can Create Manual Javah Builder ...

16. Header file for C/C++ Programs Run javah utility on the class file to create a header file for C/C++ programs.

17. C/C++ Implementation Write Your C/C++ Code JNI environment interface function

18. What is Javah ? Java is bundled with JDK .it Has command to generate c header file from a java class. this file provide connective glue that allow your java and c code to intract. How to find your Javah from Terminal : Which Javah

19. Setting up Automatic NDK Builds in Eclipse Start by right clicking on your android project and select Properties. In the resulting dialog, choose the Builders entry in the list to the left and press the New... button:

20. Here We Go .......... NDK Build

21. NDK Build Finish ....

22. Generated Shared Library .So File The Android OS loads the Java code and starts executing it The Java code calls System.loadLibrary() to load a native library. The Java code starts calling functions from the native code.

23. Final Output

24. Thank You