Introduction

Thanks to the Android native application APIs, it is possible to write an Android application with pure native code since Android API level 9 (Android 2.3, Gingerbread). That is, not a single line of Java code is needed. The Android native APIs are defined in several header files under the <NDK root>/platforms/android-<API level>/arch-arm/usr/include/android/ folder. Based on the features provided by the functions defined in these header files, they can be grouped as follows:

• Activity lifecycle management:

  • native_activity.h

  • looper.h

• Windows management:

  • rect.h

  • window.h

  • native_window.h

  • native_window_jni.h

• Input (including key and motion events) and sensor events:

  • input.h

  • keycodes.h

  • sensor.h

• Assets, configuration, and storage management:

  • configuration.h

  • asset_manager.h

  • asset_manager_jni.h

  • storage_manager.h

  • obb.h

In addition, Android NDK also provides a static library named native app glue to help create and manage native activities. The source code of this library can be found under the...