Android NDK is all about injecting high performance and portable code into your mobile apps by exploiting the maximum speed of these mobile devices. Android NDK allows you to write fast code for intensive tasks and port existing code to Android and non-Android platforms. Alternatively, if you have an application with multiple lines of C code, using NDK can considerably reduce the project development process. This is one of the most efficient operating systems for multimedia and games.
This Beginner's Guide will show you how to create applications enabled by C/C++ and integrate them with Java. By using this practical step-by-step guide, and gradually practicing your new skills using the tutorials, tips, and tricks, you will learn how to run C/C++ code embedded in a Java application or in a standalone application.
The books starts by teaching you how to access native API and port libraries used in some of the most successful Android applications. Next, you will move on to create a real native application project through the complete implementation of a native API and porting existing third-party libraries. As we progress through the chapters, you will gain a detailed understanding of rendering graphics and playing sound with OpenGL ES and OpenSL ES, which are becoming the new standard in mobility. Moving forward, you will learn how to access the keyboard and input peripherals, and read accelerometer or orientation sensors. Finally, you will dive into more advanced topics, such as RenderScript.
By the end of the book, you will be familiar enough with the key elements to start exploiting the power and portability of native code.
Chapter 1, Setting Up Your Environment, covers all the prerequisite packages installed on our system. This chapter also covers installing the Android Studio bundle, which contains both the Android Studio IDE and the Android SDK.
Chapter 2, Starting a Native Android Project, discusses how to build our first sample application using command-line tools and how to deploy it on an Android device. We also create our first native Android projects using Eclipse and Android Studio.
Chapter 3, Interfacing Java and C/C++ with JNI, covers how to make Java communicate with C/C++. We also handle Java object references in native code using Global references, and we learn the differences of Local references. Finally, we raise and check Java exceptions in native code.
Chapter 4, Calling Java Back from Native Code, calls Java code from native code with the JNI Reflection API. We also process bitmaps natively with the help of JNI and decode a video feed by hand.
Chapter 5, Writing a Fully Native Application, discusses creating NativeActivity that polls activity events to start or stop native code accordingly We also access the display window natively, such as a bitmap to display raw graphics. Finally, we retrieve time to make the application adapt to device speed using a monotonic clock.
Chapter 6, Rendering Graphics with OpenGL ES, covers how to initialize an OpenGL ES context and bind it to an Android window. Then, we see how to turn libpng into a module and load a texture from a PNG asset.
Chapter 7, Playing Sound with OpenSL ES, covers how to initialize OpenSL ES on Android. Then, we learn how to play background music from an encoded file and in-memory sounds with a sound buffer queue. Finally, we discover how to record and play a sound in a way that is thread-safe and non-blocking.
Chapter 8, Handling Input Devices and Sensors, discusses multiple ways to interact with Android from native code. More precisely, we discover how to attach an input queue to the Native App Glue event loop.
Chapter 9, Porting Existing Libraries to Android, covers how to activate the STL with a simple flag in the NDK makefile system. We port the Box2D library into an NDK module that is reusable among Android projects.
Chapter 10, Intensive Computing with RenderScript, introduces RenderScript, an advanced technology to parallelize intensive computation tasks. We also see how to use predefined RenderScript with built-in Intrinsics, which is currently mainly dedicated to image processing.