The Android NDK is a companion tool to the Android SDK that lets you build performance-critical portions of your apps in native code. It provides headers and libraries that allow you to build activities, handle user input, use hardware sensors, access application resources, and more, when programming in C or C++. If you write native code, your applications are still packaged into an .apk file and they still run inside of a virtual machine on the device. The fundamental Android application model does not change.
Using native code does not result in an automatic performance increase, but always increases application complexity. If you have not run into any limitations using the Android framework APIs, you probably do not need the NDK. Read What is the NDK? for more information about what the NDK offers and whether it will be useful to you.
The NDK is designed for use only in conjunction with the Android SDK. If you have not already installed and setup the Android SDK, please do so before downloading the NDK.
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The sections below provide information and notes about successive releases of the NDK, as denoted by revision number.
This release of the NDK does not include any new features compared to r5. The r5b release addresses the following problems in the r5 release:
ndk-buildissues are fixed:
cygpath -mfrom GNU Make for every source or object file, which caused problems with very large source trees. In case this doesn't work properly, define
NDK_USE_CYGPATH=1in your environment to use
NDK_MODULE_PATHenvironment variable from working properly when it contained multiple directories separated with a colon.
prebuilt-common.shscript contains fixes to check the compiler for 64-bit generated machine code, instead of relying on the host tag, which allows the 32-bit toolchain to rebuild properly on Snow Leopard. The toolchain rebuild scripts now also support using a 32-bit host toolchain.
INET_ADDRSTRLENwas added to
IN6_IS_ADDR_MC_GLOBALwere added to
<asm/byteorder.h>to allow compilation with
This release of the NDK includes many new APIs, most of which are introduced to
support the development of games and similar applications that make extensive use
of native code. Using the APIs, developers have direct native access to events, audio,
graphics and window management, assets, and storage. Developers can also implement the
Android application lifecycle in native code with help from the new
NativeActivity class. For detailed information describing the changes in this
release, read the
CHANGES.HTML document included in the downloaded NDK package.
./configure && make. See docs/STANDALONE-TOOLCHAIN.html for the details. The binaries for GCC 4.4.0 are still provided, but the 4.2.1 binaries were removed.
cpufeatureshelper library that improves reporting of the CPU type (some devices previously reported ARMv7 CPU when the device really was an ARMv6). We recommend developers that use this library to rebuild their applications then upload to Market to benefit from the improvements.
native-activity, to demonstrate how to write a native activity.
Includes fixes for several issues in the NDK build and debugging scripts — if you are using NDK r4, we recommend downloading the NDK r4b build. For detailed information describing the changes in this release, read the CHANGES.TXT document included in the downloaded NDK package.
armeabi-v7a. The new ABI extends the existing
armeabiABI to include these CPU instruction set extensions:
cpufeaturesstatic library (with sources) that lets your app detect the host device's CPU features at runtime. Specifically, applications can check for ARMv7-A support, as well as VFPv3-D32 and NEON support, then provide separate code paths as needed.
hello-neon, that illustrates how to use the
cpufeatureslibrary to check CPU features and then provide an optimized code path using NEON instrinsics, if supported by the CPU.
Bitmapobjects from native code.
hello-gl2, that illustrates the use of OpenGL ES 2.0 vertex and fragment shaders.
Originally released as "Android 1.6 NDK, Release 1".
san-angeles, that renders 3D graphics through the native OpenGL ES APIs, while managing activity lifecycle with a
Originally released as "Android 1.5 NDK, Release 1".
Installing the NDK on your development computer is straightforward and involves extracting the NDK from its download package.
Before you get started make sure that you have downloaded the latest Android SDK and upgraded your applications and environment as needed. The NDK is compatible with older platform versions but not older versions of the SDK tools. Also, take a moment to review the System and Software Requirements for the NDK, if you haven't already.
To install the NDK, follow these steps:
android-ndk-<version>. You can rename the NDK directory if necessary and you can move it to any location on your computer. This documentation refers to the NDK directory as
You are now ready to start working with the NDK.
Once you've installed the NDK successfully, take a few minutes to read the documentation
included in the NDK. You can find the documentation in the
directory. In particular, please read the OVERVIEW.HTML document completely, so that you
understand the intent of the NDK and how to use it.
If you used a previous version of the NDK, take a moment to review the list of NDK changes in the CHANGES.HTML document.
Here's the general outline of how you work with the NDK tools:
<project>/jni/Android.mkto describe your native sources to the NDK build system
cd <project> <ndk>/ndk-build
The build tools copy the stripped, shared libraries needed by your application to the proper location in the application's project directory.
For complete information on all of the steps listed above, please see the documentation included with the NDK package.
The NDK includes sample Android applications that illustrate how to use native code in your Android applications. For more information, see Sample Applications.
If you have questions about the NDK or would like to read or contribute to discussions about it, please visit the android-ndk group and mailing list.