Android Native Development Kit Cookbook

Chapter 2. Java Native Interface

In this chapter, we will cover the following recipes:

• Loading native libraries and registering native methods
• Passing parameters and receiving returns in primitive types
• Manipulating strings in JNI
• Managing references in JNI
• Manipulating classes in JNI
• Manipulating objects in JNI
• Manipulating arrays in JNI
• Accessing Java static and instance fields in native code
• Calling static and instance methods from native code
• Caching jfieldID, jmethodID, and reference data to improve performance
• Checking errors and handling exceptions in JNI
• Integrating assembly code in JNI

Introduction

Programming with Android NDK is essentially writing code in both Java and native languages such as C, C++, and assembly. Java code runs on Dalvik Virtual ...