|Mac OS X (intel)||android-ndk-r8-darwin-x86.tar.bz2||96650992 bytes||81ce5de731f945692123b377afe0bad9|
|Linux 32/64-bit (x86)||android-ndk-r8-linux-x86.tar.bz2||88310791 bytes||5c9afc9695ad67c61f82fbf896803c05|
The NDK is a toolset that allows you to implement parts of your app using native-code languages such as C and C++. For certain types of apps, this can be helpful so that you may reuse existing code libraries written in these languages and possibly increased performance.
Before downloading the NDK, you should understand that the NDK will not benefit most apps. As a developer, you need to balance its benefits against its drawbacks. Notably, using native code on Android generally does not result in a noticable performance improvement, but it always increases your app complexity. In general, you should only use the NDK if it is essential to your app—never because you simply prefer to program in C/C++.
Typical good candidates for the NDK are self-contained, CPU-intensive operations that don't allocate much memory, such as signal processing, physics simulation, and so on. When examining whether or not you should develop in native code, think about your requirements and see if the Android framework APIs provide the functionality that you need.
The sections below provide information and notes about successive releases of the NDK, as denoted by revision number.
This release of the NDK includes support for MIPS ABI and a few additional fixes.
docs/CPU-MIPS.htmlin the NDK package.
By default, code is generated for ARM-based devices. You can add
APP_ABI definition in your
Application.mk file to build
for MIPS platforms. For example, the following line instructs
to build your code for three distinct ABIs:
APP_ABI := armeabi armeabi-v7a mips
Unless you rely on architecture-specific assembly sources, such as ARM assembly
code, you should not need to touch your
Android.mk files to build MIPS
--arch=mipsoption when calling
docs/STANDALONE-TOOLCHAIN.htmlfor more details.
Note: To ensure that your applications are available to users only if their devices are capable of running them, Google Play filters applications based on the instruction set information included in your application ? no action is needed on your part to enable the filtering. Additionally, the Android system itself also checks your application at install time and allows the installation to continue only if the application provides a library that is compiled for the device's CPU architecture.
dynamic_cast<D>(b)of base class object
bto derived class
Dis incorrectly adjusted in the opposite direction from the base class. (Issue 28721)
make-standalone-toolchain.shfails to copy
ndk-build.cmdto ensure that
ndk-build.cmdworks correctly even if the user has redefined the
SHELLenvironment variable, which may be changed when installing a variety of development tools in Windows environments.
This release of the NDK includes an important fix for Tegra2-based devices, and a few additional fixes and improvements:
NDK_OUTenvironment variable. When defined, this variable is used to store all intermediate generated files, instead of
$PROJECT_PATH/obj. The variable is also recognized by
This change forces the NDK build system to put most linker or archiver options
into list files, as a work-around for command-line length limitations.
docs/ANDROID-MK.html for details.
android_getCpuCount()implementation in the
cpufeatureshelper library. On certain devices, where cores are enabled dynamically by the system, the previous implementation would report the total number of active cores the first time the function was called, rather than the total number of physically available cores.
This release of the NDK includes fixes for native Windows builds, Cygwin and many other improvements:
sys/atomics.hto avoid correctness issues on some multi-core ARM-based devices. Rebuild your unmodified sources with this version of the NDK and this problem should be completely eliminated. For more details, read
binutils2.19 to fix debugging issues that appeared in NDK r7 (which switched to
ndk-buildon 32-bit Linux. A packaging error put a 64-bit version of the
prebuilt/linux-x86/binin NDK r7.
ndk-build.cmd). Other build modes were not affected. The fixes include:
ndk-build.cmdfrom a directory that was not the top of your project path (e.g., in any sub-directory of it).
-lstdc++(i.e., linking against the GNU
libstdc++C++ runtime). You should use
-lgnustl_sharedif you want to link against the shared library version or
-lstdc++for the static version.
docs/STANDALONE-TOOLCHAIN.html for more details about this fix.
gnustl_sharedon Cygwin. The linker complained that it couldn't find
libsupc++.aeven though the file was at the right location.
libstdc++runtime, the compiler will no longer forcibly enable exceptions and RTTI. This change results in smaller code.
If you need these features, you must do one of the following:
'rtti'or both in your
docs/APPLICATION-MK.htmlfor more details.
ndk-gdbnow works properly when your application has private services running in independent processes. It debugs the main application process, instead of the first process listed by
ps, which is usually a service process.
LOCAL_ARM_MODEvalue and always compile certain source files (but not all) to 32-bit instructions.
stlport: Refresh the sources to match the Android platform version. This update fixes a few minor bugs:
For complete details, see the commit log.
stlport: Removed 5 unnecessary static initializers from the library.
cpu-featureshelper library was updated to report three optional x86 CPU features (
docs/CPU-FEATURES.htmlfor more details.
docs/NDK-BUILD.htmlwas updated to mention
NDK_APP_APPLICATION_MKto select a custom
ndk-buildno longer creates an empty "NUL" file in the current directory when invoked.
ndk-builddoes not try to use the native Windows tools under
$NDK/prebuilt/windows/binwith certain versions of Cygwin and/or GNU Make.
This release of the NDK includes new features to support the Android 4.0 platform as well as many other additions and improvements:
<OMXAL/OpenMAXAL_Android.h>headers allow applications targeting API level 14 to perform multimedia output directly from native code by using a new Android-specific buffer queue interface. For more details, see
NDK_CCACHEenvironment variable to
ccache(or the path to your
ccachebinary). When declared, the NDK build system automatically uses CCache when compiling any source file. For example:
Note: CCache is not included in the NDK release so you must have it installed prior to using it. For more information about CCache, see http://ccache.samba.org.
allto indicate that you want to build your NDK modules for all the ABIs supported by your given NDK release. This means that either one of the following two lines in your
Application.mkare equivalent with this release:
APP_ABI := all APP_ABI := armeabi armeabi-v7a x86
This also works if you define
APP_ABI when calling
ndk-build from the command-line, which is a quick way to check that your
project builds for all supported ABIs without changing the project's
Application.mk file. For example:
Android.mkthat allows you to declare which C++ features (RTTI or Exceptions) your module uses. This ensures that the final linking works correctly if you have prebuilt modules that depend on these features. See
docs/CPLUSPLUS-SUPPORT.htmlfor more details.
$NDK/ndk-buildfrom your project path, the paths to the source, object, and binary files that are passed to the build commands are significantly shorter now, because they are passed relative to the current directory. This is useful when building projects with a lot of source files, to avoid limits on the maximum command line length supported by your host operating system. The behavior is unchanged if you invoke
ndk-buildfrom a sub-directory of your project tree, or if you define
NDK_PROJECT_PATHto point to a specific directory.
ndk-build.cmdscript from the command line from your project path. The script takes exactly the same arguments as the original
ndk-buildscript. The Windows NDK package comes with its own prebuilt binaries for GNU Make, Awk and other tools required by the build. You should not need to install anything else to get a working build system.
ndk-gdb does not work on
Windows, so you still need Cygwin to debug.
This feature is still experimental, so feel free to try it and report issues on the public bug database or public forum. All samples and unit tests shipped with the NDK succesfully compile with this feature.
APP_MODULESis not defined in your
Application.mk. For example, if a top-level module
fooimports a module
bar, then both
libbar.soare copied to the install location. Previously, only
libfoo.sowas copied, unless you listed
APP_MODULEStoo. If you define
APP_MODULESexplicitly, the behavior is unchanged.
ndk-gdbnow works correctly for activities with multiple categories in their MAIN intent filters.
fooimports static library
barthat imports static library
libfoo.sowill now be linked against both
docs/NATIVE-ACTIVITY.HTML: Fixed typo. The minimum API level should be 9, not 8 for native activities.
docs/STABLE-APIS.html: Added missing documentation listing EGL as a supported stable API, starting from API level 9.
download-toolchain-sources.sh: Updated to download the toolchain sources from android.googlesource.com, which is the new location for the AOSP servers.
gabi++. More details about it are available in the updated
gnustl_sharedthat corresponds to the shared library version of GNU libstdc++ v3 (GPLv3 license). See more info at
LOCAL_CPP_EXTENSION. For example, to compile both
bar.cxxas C++ sources, declare the following:
LOCAL_CPP_EXTENSION := .cpp .cxx
The extensions that are available depend on your actual device and GPU drivers,
not the platform version the device runs on. The header changes simply add new
constants and types to make it easier to use the extensions when they have been
following list describes the newly supported extensions:
This release of the NDK does not include any new features compared to r6. The r6b release addresses the following issues in the r6 release:
APP_ABI="armeabi x86"is used for multi-architecture builds.
atexit()usage in shared libraries with the x86standalone toolchain.
make-standalone-toolchain.sh --arch=x86. It used to fail to copy the proper GNU libstdc++ binaries to the right location.
__dso_handlesymbol (ARM only).
$(SYSROOT)/usr/includefor x86 builds. See the bug for more information.
size_tin x86-specific systems when they are used with the x86 standalone toolchain.
This release of the NDK includes support for the x86 ABI and other minor changes.
For detailed information describing the changes in this release, read the
CHANGES.HTML document included in the NDK package.
docs/CPU-X86.htmlin the NDK package.
By default, code is generated for ARM-based devices, but you can add x86 to your
APP_ABI definition in your
Application.mk file to build
for x86 platforms. For example, the following line instructs
to build your code for three distinct ABIs:
APP_ABI := armeabi armeabi-v7a x86
Unless you rely on ARM-based assembly sources, you shouldn't need to touch
Android.mk files to build x86 machine code.
--toolchain=x86-4.4.3option when calling
docs/STANDALONE-TOOLCHAIN.htmlfor more details.
ndk-stacktool lets you translate stack traces in
logcatthat are generated by native code. The tool translates instruction addresses into a readable format that contains things such as the function, source file, and line number corresponding to each stack frame. For more information and a usage example, see
arm-eabi-4.4.0, which had been deprecated since NDK r5, has been removed from the NDK distribution.
This release of the NDK does not include any new features compared to r5b. The r5c release addresses the following problems in the r5b release:
ndk-build: Fixed a rare bug that appeared when trying to perform parallel builds of debuggable projects.
LOCAL_WHOLE_STATIC_LIBRARIESto work correctly with the new toolchain and added documentation for this in
gnustl_staticcrashed when run on platform releases older than API level 8 (Android 2.2).
ndk-gdb: Fixed a bug that caused a segmentation fault when debugging Android 3.0 or newer devices.
<android/input.h>: Two functions that were introduced in API level 9 (Android 2.3) were incorrect and are fixed. While this breaks the source API, the binary interface to the system is unchanged. The incorrect functions were missing a
history_indexparameter, and the correct definitions are shown below:
float AMotionEvent_getHistoricalRawX(const AInputEvent* motion_event, size_t pointer_index, size_t history_index); float AMotionEvent_getHistoricalRawY(const AInputEvent* motion_event, size_t pointer_index, size_t history_index);
LOCAL_SRC_FILES. This was not the case previously because the files were grouped by source extensions instead.
import-modulefails, it now prints the list of directories that were searched. This is useful to check that the
NDK_MODULE_PATHdefinition used by the build system is correct.
import-modulesucceeds, it now prints the directory where the module was found to the log (visible with
ndk-gdb: Better detection of
adb shellfailures and improved error messages.
<pthread.h>: Fixed the definition of
PTHREAD_RWLOCK_INITIALIZERfor API level 9 (Android 2.3) and higher.
LOCAL_ARM_NEONwas set to true (typo in
.Sfiles were okay).
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 Google Play 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".
The sections below describe the system and software requirements for using the Android NDK, as well as platform compatibility considerations that affect appplications using libraries produced with the NDK.
|Native Code CPU Architecture Used||Compatible Android Platform(s)|
|ARM, ARM-NEON||Android 1.5 (API Level 3) and higher|
|x86||Android 2.3 (API Level 9) and higher|
|MIPS||Android 2.3 (API Level 9) and higher|
These requirements mean you can use native libraries produced with the NDK in applications that are deployable to ARM-based devices running Android 1.5 or later. If you are deploying native libraries to x86 and MIPS-based devices, your application must target Android 2.3 or later.
<uses-sdk>element in its manifest file, with an
android:minSdkVersionattribute value of "3" or higher. For example:
<manifest> <uses-sdk android:minSdkVersion="3" /> ... </manifest>
android:minSdkVersionattribute value, as shown in the following table.
|OpenGL ES Version Used||Compatible Android Platform(s)||Required uses-sdk Attribute|
|OpenGL ES 1.1||Android 1.6 (API Level 4) and higher||
|OpenGL ES 2.0||Android 2.0 (API Level 5) and higher||
For more information about API Level and its relationship to Android platform versions, see Android API Levels.
<uses-feature>element in its manifest, with an
android:glEsVersionattribute that specifies the minimum OpenGl ES version required by the application. This ensures that Google Play will show your application only to users whose devices are capable of supporting your application. For example:
<manifest> <uses-feature android:glEsVersion="0x00020000" /> ... </manifest>
For more information, see the
Bitmappixel buffers or utilizes native activities, the application containing the library can be deployed only to devices running Android 2.2 (API level 8) or higher. To ensure compatibility, make sure that your application declares
<uses-sdk android:minSdkVersion="8" />attribute value in its manifest.
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 Android framework provides two ways to use native code:
Write a native activity, which allows you to implement the lifecycle callbacks in native
code. The Android SDK provides the
NativeActivity class, which is a
convenience class that notifies your
native code of any activity lifecycle callbacks (
onResume(), etc). You can implement the callbacks in your native code to handle
these events when they occur. Applications that use native activities must be run on Android
2.3 (API Level 9) or later.
You cannot access features such as Services and Content Providers natively, so if you want to use them or any other framework API, you can still write JNI code to do so.
The NDK contains the APIs, documentation, and sample applications that help you write your native code. Specifically:
.apk) that can be deployed on Android devices
The latest release of the NDK supports the following instruction sets:
docs/CPU-ARCH-ABIS.htmlfor more information)
docs/CPU-ARM-NEON.htmlfor more information)
docs/CPU-X86.htmlfor more information)
docs/CPU-MIPS.htmlfor more information)
ARMv5TE machine code will run on all ARM-based Android devices. ARMv7-A will run only on
devices such as the Verizon Droid or Google Nexus One that have a compatible CPU. The main
difference between the two instruction sets is that ARMv7-A supports hardware FPU, Thumb-2, and
NEON instructions. You can target either or both of the instruction sets — ARMv5TE is the
default, but switching to ARMv7-A is as easy as adding a single line to the application's
Application.mk file, without needing to change anything else in the file. You can also build for
both architectures at the same time and have everything stored in the final
Complete information is provided in the CPU-ARCH-ABIS.HTML in the NDK package.
The NDK provides stable headers for libc (the C library), libm (the Math library), OpenGL ES (3D graphics library), the JNI interface, and other libraries, as listed in the Development tools section.
The NDK includes a set of cross-toolchains (compilers, linkers, etc..) that can generate native ARM binaries on Linux, OS X, and Windows (with Cygwin) platforms.
It provides a set of system headers for stable native APIs that are guaranteed to be supported in all later releases of the platform:
The NDK also provides a build system that lets you work efficiently with your sources, without having to handle the toolchain/platform/CPU/ABI details. You create very short build files to describe which sources to compile and which Android application will use them — the build system compiles the sources and places the shared libraries directly in your application project.
Important: With the exception of the libraries listed above, native system libraries in the Android platform are not stable and may change in future platform versions. Your applications should only make use of the stable native system libraries provided in this NDK.
The NDK package includes a set of documentation that describes the capabilities of the NDK and
how to use it to create shared libraries for your Android applications. In this release, the
documentation is provided only in the downloadable NDK package. You can find the documentation in
<ndk>/docs/ directory. Included are these files (partial listing):
cpufeaturesstatic library that lets your application code detect the target device's CPU family and the optional features at runtime.
Additionally, the package includes detailed information about the "bionic" C library provided
with the Android platform that you should be aware of, if you are developing using the NDK. You
can find the documentation in the
The NDK includes sample applications that illustrate how to use native code in your Android applications:
hello-jni— a simple application that loads a string from a native method implemented in a shared library and then displays it in the application UI.
two-libs— a simple application that loads a shared library dynamically and calls a native method provided by the library. In this case, the method is implemented in a static library imported by the shared library.
san-angeles— a simple application that renders 3D graphics through the native OpenGL ES APIs, while managing activity lifecycle with a
hello-gl2— a simple application that renders a triangle using OpenGL ES 2.0 vertex and fragment shaders.
hello-neon— a simple application that shows how to use the
cpufeatureslibrary to check CPU capabilities at runtime, then use NEON intrinsics if supported by the CPU. Specifically, the application implements two versions of a tiny benchmark for a FIR filter loop, a C version and a NEON-optimized version for devices that support it.
bitmap-plasma— a simple application that demonstrates how to access the pixel buffers of Android
Bitmapobjects from native code, and uses this to generate an old-school "plasma" effect.
native-activity— a simple application that demonstrates how to use the native-app-glue static library to create a native activity
native-plasma— a version of bitmap-plasma implemented with a native activity.
For each sample, the NDK includes the corresponding C source code and the necessary Android.mk
and Application.mk files. There are located under
and their source code can be found under
You can build the shared libraries for the sample apps by going into
<ndk>/samples/<name>/ then calling the
The generated shared libraries will be located under
<ndk>/samples/<name>/libs/armeabi/ for (ARMv5TE machine code) and/or
<ndk>/samples/<name>/libs/armeabi-v7a/ for (ARMv7 machine code).
Next, build the sample Android applications that use the shared libraries:
<ndk>/samples/<name>/. Then, set up an AVD, if necessary, and build/run the application in the emulator.
androidtool to create the build file for each of the sample projects at
<ndk>/samples/<name>/. Then set up an AVD, if necessary, build your project in the usual way, and run it in the emulator.
For more information about developing with the Android SDK tools and what you need to do to create, build, and run your applications, see the Overview section for developing on Android.
The hello-jni sample is a simple demonstration on how to use JNI from an Android application. The HelloJni activity receives a string from a simple C function and displays it in a TextView.
The main components of the sample include:
resdirectories, and a main activity)
jni/directory that includes the implemented source file for the native code as well as the Android.mk file
tests/directory that contains unit test code.
androidtool to update the project so it generates a build.xml file that you can use to build the sample.
android update project -p . -s
cd <ndk-root>/samples/hello-jni <ndk_root>/ndk-build
ant debug adb install bin/HelloJni-debug.apk
When you run the application on the device, the string
Hello JNI should appear on
your device. You can explore the rest of the samples that are located in the
<ndk-root>/samples directory for more examples on how to use the JNI.
The native-activity sample provided with the Android NDK demonstrates how to use the android_native_app_glue static library. This static library makes creating a native activity easier by providing you with an implementation that handles your callbacks in another thread, so you do not have to worry about them blocking your main UI thread. The main parts of the sample are described below:
resdirectories). The AndroidManifest.xml declares that the application is native and specifies the .so file of the native activity. See
NativeActivityfor the source or see the
jni/directory contains the native activity, main.c, which uses the
android_native_app_glue.hinterface to implement the activity. The Android.mk that describes the native module to the build system also exists here.
To build this sample application:
androidtool to update the project so it generates a build.xml file that you can use to build the sample.
android update project -p . -s
cd <ndk-root>/platforms/samples/android-9/samples/native-activity <ndk_root>/ndk-build
ant debug adb install bin/NativeActivity-debug.apk