Chapter 1, Hello NDK, covers how to set up an Android NDK development environment in Windows, Linux, and MacOS. We will write a "Hello NDK" application at the end of the chapter.

Chapter 2, Java Native Interface, describes the usage of JNI in detail. We will call native methods from the Java code and vice versa.

Chapter 3, Build and Debug NDK Applications, demonstrates building native code from a command line and Eclipse IDE. We will also look at debugging native code with gdb, cgdb, eclipse, and so on.

Chapter 4, Android NDK OpenGL ES API, illustrates OpenGL ES 1.x and 2.0 APIs. We will cover 2D drawing, 3D graphics, texture mapping, EGL, and so on.

Chapter 5, Android Native Application API, discusses Android native application APIs, including managing native windows, accessing sensors, handling input events, managing assets, and so on. We will see how to write a pure native app in this chapter.

Chapter 6, Android NDK Multithreading, depicts Android multithreading API. We will cover creating and terminating native threads, various thread synchronization techniques (mutex, conditional variables, semaphore, and reader/writer lock), thread scheduling, and thread data management.

Chapter 7, Other Android NDK API, discusses a few more Android libraries, including jnigraphics, the dynamic linker library, the zlib compression library, the OpenSL ES library, and the OpenMAX AL library.

Chapter 8, Porting and Using Existing Libraries with Android NDK, describes various techniques of porting and using existing C/C++ libraries with NDK. We will port the boost library at the end of the chapter.

Chapter 9, Porting Existing Applications to Android with NDK, provides a step-by-step guide for porting an existing application to Android with NDK. We use an open source image resizing program as an example.

Bonus Chapter 1, Developing Multimedia Applications with NDK, demonstrates how to write multimedia applications with the ffmpeg library. We will port the ffmpeg library and use the library APIs to write a frame grabber application.

Bonus Chapter 2, Developing Games with NDK, discusses writing games with NDK. We will port the Wolfenstein 3D game to show how to set up game display, add game control, and enable audio effects for a game.

You can download the bonus chapters from http://www.packtpub.com/sites/default/files/downloads/Developing_Multimedia_Applications_with_NDK.pdf and http://www.packtpub.com/sites/default/files/downloads/Developing_Games_with_NDK.pdf.

A computer with Windows, Ubuntu Linux, or MacOS installed is necessary (Linux or MacOS is preferable). Although we can run Android apps with an emulator, it is slow and inefficient for Android development. Therefore, it is recommended to have an Android device.

The book assumes a basic understanding of C and C++ programming languages. You should also be familiar with Java and Android SDK.

Note that the sample code of this book is based on Android ndk r8 unless otherwise stated, since it is the latest version of NDK at the time of writing. By the time the book is published, there should be newer versions. The code should also run on any newer versions. Therefore we can install NDK r8 or later.

The book is written for anyone who is interested in writing native code for Android. The chapters are arranged from basic to intermediate to advanced, and they are relatively independent. Readers who are new to NDK are recommended to read from the beginning to the end, while readers who are familiar with NDK can pick up any specific chapters or even specific recipes.

In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

Code words in text are shown as follows: "Windows NDK comes with a new ndk-build.cmd build script."

A block of code is set as follows:

#include <string.h>
#include <jni.h>

jstring 
Java_cookbook_chapter1_HelloNDKActivity_naGetHelloNDKStr(JNIEnv* pEnv,  jobject pObj)
{
    return (*pEnv)->NewStringUTF(pEnv, "Hello NDK!");
}

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE  := framegrabber
LOCAL_SRC_FILES := framegrabber.c
#LOCAL_CFLAGS := -DANDROID_BUILD
LOCAL_LDLIBS := -llog -ljnigraphics -lz  
LOCAL_STATIC_LIBRARIES := libavformat_static libavcodec_static libswscale_static libavutil_static
include $(BUILD_SHARED_LIBRARY)
$(call import-module,ffmpeg-1.0.1/android/armv5te)

Any command-line input or output is written as follows:

$sudo update-java-alternatives -s <java name>

New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: "Go to Control Panel | System and Security | System | Advanced system settings."

Feedback from our readers is always welcome. Let us know what you think about this book—what you liked or may have disliked. Reader feedback is important for us to develop titles that you really get the most out of.

To send us general feedback, simply send an e-mail to <[email protected]>, and mention the book title via the subject of your message.

If there is a topic that you have expertise in and you are interested in either writing or contributing to a book, see our author guide on www.packtpub.com/authors.

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