Book Image

Android Native Development Kit Cookbook

By : Liu Feipeng
Book Image

Android Native Development Kit Cookbook

By: Liu Feipeng

Overview of this book

Building Android applications would usually mean that you spend all of your time working in Java. There are however times when this is not the most efficient or best method for the application being built. This is where Android NDK comes in. Android NDK allows the developer to write in Native C/C++, giving you the power to reuse code and libraries and also, in most cases, increase the speed and efficiency of your application.The "Android Native Development Kit Cookbook" will help you understand the development, building, and debugging of your native Android applications. We will discover and learn JNI programming and essential NDK APIs such as OpenGL ES, and the native application API. We will then explore the process of porting existing libraries and software to NDK. By the end of this book you will be able to build your own apps in NDK apps."Android Native Development Kit Cookbook" begins with basic recipes that will help you in the building and debugging of native apps, and JNI programming. The recipes cover various topics of application development with Android NDK such as OpenGL programming and Multimedia programming. We will begin with a simple recipe, Hello NDK, before moving on to cover advanced topics with recipes on OpenGL ES that focus on 2D and 3D graphics, as well as recipes that discuss working with NDK and external APIs. If you are looking for ways to make your application available in Android and take measures to boost your application's performance, then this Cookbook is for you.
Table of Contents (16 chapters)
Android Native Development Kit Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Accessing Java static and instance fields in the native code


We have demonstrated how to pass parameters of different types to native methods and return data back to Java. This is not the only way of sharing data between the native code and Java code. This recipe covers another method—accessing Java fields from the native code.

Getting ready

We're going to cover how to access Java fields of different types, including primitive types, strings, instance objects, and arrays. The following recipes should be read first before reading this recipe:

  • Passing parameters and receiving returns in primitive types

  • Manipulating strings in JNI

  • Manipulating classes in JNI

  • Manipulating objects in JNI

  • Manipulating arrays in JNI

Readers are also expected to be familiar with Java reflection API.

How to do it…

Follow these steps to create a sample Android project that demonstrates how to access Java static and instance fields from the native code:

  1. Create a project named AccessingFields. Set the package name as cookbook...