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android_frameworks_base/docs/html/tools/sdk/ndk/index.jd
Scott Main a39d13c1be docs: move NDK into Download section 
Change-Id: I7c16b465c45ac4456f689ff81300f65f767acb12
2012-06-22 17:15:11 -07:00

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ndk=true
ndk.win_download=android-ndk-r8-windows.zip
ndk.win_bytes=109928336
ndk.win_checksum=37b1a2576f28752fcc09e1b9c07e3f14
ndk.mac_download=android-ndk-r8-darwin-x86.tar.bz2
ndk.mac_bytes=96650992
ndk.mac_checksum=81ce5de731f945692123b377afe0bad9
ndk.linux_download=android-ndk-r8-linux-x86.tar.bz2
ndk.linux_bytes=88310791
ndk.linux_checksum=5c9afc9695ad67c61f82fbf896803c05
page.title=Android NDK
@jd:body
<div id="qv-wrapper">
<div id="qv">
<h2>In this document</h2>
<ol>
<li><a href="#Downloads">Downloads</a></li>
<li><a href="#Revisions">Revisions</a></li>
<li><a href="#Reqs">System and Software Requirements</a></li>
<li><a href="#Installing">Installing the NDK</a></li>
<li><a href="#GetStarted">Getting Started with the NDK</a>
<ol>
<li><a href="#Using">Using the NDK</a></li>
</ol>
</li>
<li><a href="#Contents">Contents of the NDK</a>
<ol>
<li><a href="#Tools">Development tools</a></li>
<li><a href="#Docs">Documentation</a></li>
<li><a href="#Samples">Sample apps</a></li>
</ol>
</li>
</ol>
</div>
</div>
<p>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.</p>
<p>Before downloading the NDK, you should understand that <strong>the NDK
will not benefit most apps</strong>. 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&mdash;never because you simply prefer to program in C/C++.</p>
<p>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.</p>
<h2 id="Downloads">Downloads</h2>
<script>
$('#Downloads').after($('#download-table'));
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<h2 id="Revisions">Revisions</h2>
<p>The sections below provide information and notes about successive releases of
the NDK, as denoted by revision number. </p>
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Android NDK, Revision 8</a> <em>(May 2012)</em>
<div class="toggleme">
<p>This release of the NDK includes support for MIPS ABI and a few additional fixes.</p>
</dl>
<dt>New features:</dt>
<dd>
<ul>
<li>Added support for the MIPS ABI, which allows you to generate machine code that runs on
compatible MIPS-based Android devices. Major features for MIPS include MIPS-specific
toolchains, system headers, libraries and debugging support. For more details regarding
MIPS support, see {@code docs/CPU-MIPS.html} in the NDK package.
<p>By default, code is generated for ARM-based devices. You can add {@code mips} to
your {@code APP_ABI} definition in your {@code Application.mk} file to build
for MIPS platforms. For example, the following line instructs {@code ndk-build}
to build your code for three distinct ABIs:</p>
<pre>APP_ABI := armeabi armeabi-v7a <strong>mips</strong></pre>
<p>Unless you rely on architecture-specific assembly sources, such as ARM assembly
code, you should not need to touch your {@code Android.mk} files to build MIPS
machine code.</p>
</li>
<li>You can build a standalone MIPS toolchain using the {@code --arch=mips}
option when calling <code>make-standalone-toolchain.sh</code>. See
{@code docs/STANDALONE-TOOLCHAIN.html} for more details.
</li>
</ul>
<p class="note"><strong>Note:</strong> 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.</p>
</dd>
<dt>Important bug fixes:</dt>
<dd>
<ul>
<li>Fixed a typo in GAbi++ implementation where the result of {@code
dynamic_cast&lt;D&gt;(b)} of base class object {@code b} to derived class {@code D} is
incorrectly adjusted in the opposite direction from the base class.
(<a href="http://code.google.com/p/android/issues/detail?id=28721">Issue 28721</a>)
</li>
<li>Fixed an issue in which {@code make-standalone-toolchain.sh} fails to copy
{@code libsupc++.*}.</li>
</ul>
</dd>
<dt>Other bug fixes:</dt>
<dd>
<ul>
<li>Fixed {@code ndk-build.cmd} to ensure that {@code ndk-build.cmd} works correctly even
if the user has redefined the {@code SHELL} environment variable, which may be changed
when installing a variety of development tools in Windows environments.
</li>
</ul>
</dd>
</dl>
</div>
</div>
<div class="toggleable closed">
<a href="#" onclick="return toggleDiv(this)"><img src=
"{@docRoot}assets/images/triangle-closed.png" class="toggle-img" height="9px" width="9px">
Android NDK, Revision 7c</a> <em>(April 2012)</em>
<div class="toggleme">
<p>This release of the NDK includes an important fix for Tegra2-based devices, and a few
additional fixes and improvements:</p>
<dl>
<dt>Important bug fixes:</dt>
<dd>
<ul>
<li>Fixed GNU STL armeabi-v7a binaries to not crash on non-NEON
devices. The files provided with NDK r7b were not configured properly,
resulting in crashes on Tegra2-based devices and others when trying to use
certain floating-point functions (e.g., {@code cosf}, {@code sinf}, {@code expf}).</li>
</ul>
</dd>
<dt>Important changes:</dt>
<dd>
<ul>
<li>Added support for custom output directories through the {@code NDK_OUT}
environment variable. When defined, this variable is used to store all
intermediate generated files, instead of {@code $PROJECT_PATH/obj}. The variable is
also recognized by {@code ndk-gdb}. </li>
<li>Added support for building modules with hundreds or even thousands of source
files by defining {@code LOCAL_SHORT_COMMANDS} to {@code true} in your {@code Android.mk}.
<p>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.
See {@code docs/ANDROID-MK.html} for details.</p>
</li>
</ul>
</dd>
<dt>Other bug fixes:</dt>
<dd>
<ul>
<li>Fixed {@code android_getCpuCount()} implementation in the {@code cpufeatures}
helper library. On certain devices, where cores are enabled dynamically by the system, the previous
implementation would report the total number of <em>active</em> cores the first time the function
was called, rather than the total number of <em>physically available</em> cores.</li>
</ul>
</dd>
</dl>
</div>
</div>
<div class="toggleable closed">
<a href="#" onclick="return toggleDiv(this)"><img src=
"{@docRoot}assets/images/triangle-closed.png" class="toggle-img" height="9px" width="9px">
Android NDK, Revision 7b</a> <em>(February 2012)</em>
<div class="toggleme">
<p>This release of the NDK includes fixes for native Windows builds, Cygwin and many other
improvements:</p>
<dl>
<dt>Important bug fixes:</dt>
<dd>
<ul>
<li>Updated {@code sys/atomics.h} to 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 {@code docs/ANDROID-ATOMICS.html}.</li>
<li>Reverted to {@code binutils} 2.19 to fix debugging issues that
appeared in NDK r7 (which switched to {@code binutils} 2.20.1).</li>
<li>Fixed {@code ndk-build} on 32-bit Linux. A packaging error put a 64-bit version
of the {@code awk} executable under {@code prebuilt/linux-x86/bin} in NDK r7.</li>
<li>Fixed native Windows build ({@code ndk-build.cmd}). Other build modes were not
affected. The fixes include:
<ul>
<li>Removed an infinite loop / stack overflow bug that happened when trying
to call {@code ndk-build.cmd} from a directory that was <em>not</em> the top of
your project path (e.g., in any sub-directory of it).</li>
<li>Fixed a problem where the auto-generated dependency files were ignored. This
meant that updating a header didn't trigger recompilation of sources that included
it.</li>
<li>Fixed a problem where special characters in files or paths, other than spaces and
quotes, were not correctly handled.</li>
</ul>
</li>
<li>Fixed the standalone toolchain to generate proper binaries when using
{@code -lstdc++} (i.e., linking against the GNU {@code libstdc++} C++ runtime). You
should use {@code -lgnustl_shared} if you want to link against the shared library
version or {@code -lstdc++} for the static version.
<p>See {@code docs/STANDALONE-TOOLCHAIN.html} for more details about this fix.</p>
</li>
<li>Fixed {@code gnustl_shared} on Cygwin. The linker complained that it couldn't find
{@code libsupc++.a} even though the file was at the right location.</li>
<li>Fixed Cygwin C++ link when not using any specific C++ runtime through
{@code APP_STL}.</li>
</ul>
</dd>
</dl>
<dl>
<dt>Other changes:</dt>
<dd>
<ul>
<li>When your application uses the GNU {@code libstdc++} runtime, the compiler will
no longer forcibly enable exceptions and RTTI. This change results in smaller code.
<p>If you need these features, you must do one of the following:</p>
<ul>
<li>Enable exceptions and/or RTTI explicitly in your modules or
{@code Application.mk}. (recommended)</li>
<li>Define {@code APP_GNUSTL_FORCE_CPP_FEATURES} to {@code 'exceptions'},
{@code 'rtti'} or both in your {@code Application.mk}. See
{@code docs/APPLICATION-MK.html} for more details.</li>
</ul>
</li>
<li>{@code ndk-gdb} now 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 {@code ps}, which is usually a service process.</li>
<li>Fixed a rare bug where NDK r7 would fail to honor the {@code LOCAL_ARM_MODE} value
and always compile certain source files (but not all) to 32-bit instructions.</li>
<li>{@code stlport}: Refresh the sources to match the Android platform version. This
update fixes a few minor bugs:
<ul>
<li>Fixed instantiation of an incomplete type</li>
<li>Fixed minor "==" versus "=" typo</li>
<li>Used {@code memmove} instead of {@code memcpy} in {@code string::assign}</li>
<li>Added better handling of {@code IsNANorINF}, {@code IsINF}, {@code IsNegNAN},
etc.</li>
</ul>
<p>For complete details, see the commit log.</p>
</li>
<li>{@code stlport}: Removed 5 unnecessary static initializers from the library.</li>
<li>The GNU libstdc++ libraries for armeabi-v7a were mistakenly compiled for
armeabi instead. This change had no impact on correctness, but using the right
ABI should provide slightly better performance.</li>
<li>The {@code cpu-features} helper library was updated to report three optional
x86 CPU features ({@code SSSE3}, {@code MOVBE} and {@code POPCNT}). See
{@code docs/CPU-FEATURES.html} for more details.</li>
<li>{@code docs/NDK-BUILD.html} was updated to mention {@code NDK_APPLICATION_MK} instead
of {@code NDK_APP_APPLICATION_MK} to select a custom {@code Application.mk} file.</li>
<li>Cygwin: {@code ndk-build} no longer creates an empty "NUL" file in the current
directory when invoked.</li>
<li>Cygwin: Added better automatic dependency detection. In the previous version, it
didn't work properly in the following cases:
<ul>
<li>When the Cygwin drive prefix was not {@code /cygdrive}.</li>
<li>When using drive-less mounts, for example, when Cygwin would translate
{@code /home} to {@code \\server\subdir} instead of {@code C:\Some\Dir}.</li>
</ul>
</li>
<li>Cygwin: {@code ndk-build} does not try to use the native Windows tools under
{@code $NDK/prebuilt/windows/bin} with certain versions of Cygwin and/or GNU Make.</li>
</ul>
</dd>
</dl>
</div>
</div>
<div class="toggleable closed">
<a href="#" onclick="return toggleDiv(this)"><img src=
"{@docRoot}assets/images/triangle-closed.png" class="toggle-img" height="9px" width="9px">
Android NDK, Revision 7</a> <em>(November 2011)</em>
<div class="toggleme">
<p>This release of the NDK includes new features to support the Android 4.0 platform as well
as many other additions and improvements:</p>
<dl>
<dt>New features</dt>
<dd>
<ul>
<li>Added official NDK APIs for Android 4.0 (API level 14), which adds the following
native features to the platform:
<ul>
<li>Added native multimedia API based on the Khronos Group OpenMAX AL? 1.0.1
standard. The new <code>&lt;OMXAL/OpenMAXAL.h&gt;</code> and
<code>&lt;OMXAL/OpenMAXAL_Android.h&gt;</code> 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
<code>docs/openmaxal/index.html</code> and <a href=
"http://www.khronos.org/openmax/">http://www.khronos.org/openmax/</a>.</li>
<li>Updated the native audio API based on the Khronos Group OpenSL ES 1.0.1?
standard. With API Level 14, you can now decode compressed audio (e.g. MP3, AAC,
Vorbis) to PCM. For more details, see <code>docs/opensles/index.html</code> and
<a href=
"http://www.khronos.org/opensles">http://www.khronos.org/opensles/</a>.</li>
</ul>
</li>
<li>Added CCache support. To speed up large rebuilds, define the
<code>NDK_CCACHE</code> environment variable to <code>ccache</code> (or the path to
your <code>ccache</code> binary). When declared, the NDK build system automatically
uses CCache when compiling any source file. For example:
<pre>
export NDK_CCACHE=ccache
</pre>
<p class="note"><strong>Note:</strong> CCache is not included in the NDK release
so you must have it installed prior to using it. For more information about CCache, see
<a href="http://ccache.samba.org">http://ccache.samba.org</a>.</p>
</li>
<li>Added support for setting <code>APP_ABI</code> to <code>all</code> to 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
<code>Application.mk</code> are equivalent with this release:
<pre>
APP_ABI := all
APP_ABI := armeabi armeabi-v7a x86
</pre>
<p>This also works if you define <code>APP_ABI</code> when calling
<code>ndk-build</code> from the command-line, which is a quick way to check that your
project builds for all supported ABIs without changing the project's
<code>Application.mk file</code>. For example:</p>
<pre>
ndk-build APP_ABI=all
</pre>
</li>
<li>Added a <code>LOCAL_CPP_FEATURES</code> variable in <code>Android.mk</code> that
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 <code>docs/ANDROID-MK.html</code> and
<code>docs/CPLUSPLUS-SUPPORT.html</code> for more details.</li>
<li>Shortened paths to source and object files that are used in build commands. When
invoking <code>$NDK/ndk-build</code> from 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 <code>ndk-build</code> from a sub-directory of your project tree, or if
you define <code>NDK_PROJECT_PATH</code> to point to a specific directory.</li>
</ul>
</dd>
<dt>Experimental features</dt>
<dd>
You can now build your NDK source files on Windows <em>without</em> Cygwin by calling the
<code>ndk-build.cmd</code> script from the command line from your project path. The
script takes exactly the same arguments as the original <code>ndk-build</code> script.
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.
<p class="caution"><strong>Important:</strong> <code>ndk-gdb</code> does not work on
Windows, so you still need Cygwin to debug.</p>
<p>This feature is still experimental, so feel free to try it and report issues on the
<a href="http://b.android.com">public bug database</a> or <a href=
"http://groups.google.com/group/android-ndk">public forum</a>. All samples and unit tests
shipped with the NDK succesfully compile with this feature.</p>
</dd>
<dt>Important bug fixes</dt>
<dd>
<ul>
<li>Imported shared libraries are now installed by default to the target installation
location (<code>libs/&lt;abi&gt;</code>) if <code>APP_MODULES</code> is not defined in
your <code>Application.mk</code>. For example, if a top-level module <code>foo</code>
imports a module <code>bar</code>, then both <code>libfoo.so</code> and
<code>libbar.so</code> are copied to the install location. Previously, only
<code>libfoo.so</code> was copied, unless you listed <code>bar</code> in your
<code>APP_MODULES</code> too. If you define <code>APP_MODULES</code> explicitly, the
behavior is unchanged.</li>
<li><code>ndk-gdb</code> now works correctly for activities with multiple categories in
their MAIN intent filters.</li>
<li>Static library imports are now properly transitive. For example, if a top-level
module <code>foo</code> imports static library <code>bar</code> that imports static
library <code>zoo</code>, the <code>libfoo.so</code> will now be linked against both
<code>libbar.a</code> and <code>libzoo.a</code>.</li>
</ul>
</dd>
<dt>Other changes</dt>
<dd>
<ul>
<li><code>docs/NATIVE-ACTIVITY.HTML</code>: Fixed typo. The minimum API level should be
9, not 8 for native activities.</li>
<li><code>docs/STABLE-APIS.html</code>: Added missing documentation listing EGL as a
supported stable API, starting from API level 9.</li>
<li><code>download-toolchain-sources.sh</code>: Updated to download the toolchain
sources from <a href="http://android.googlesource.com">android.googlesource.com</a>,
which is the new location for the AOSP servers.</li>
<li>Added a new C++ support runtime named <code>gabi++</code>. More details about it
are available in the updated <code>docs/CPLUSPLUS-SUPPORT.html</code>.</li>
<li>Added a new C++ support runtime named <code>gnustl_shared</code> that corresponds
to the shared library version of GNU libstdc++ v3 (GPLv3 license). See more info at
<code>docs/CPLUSPLUS-SUPPORT.html</code></li>
<li>Added support for RTTI in the STLport C++ runtimes (no support for
exceptions).</li>
<li>Added support for multiple file extensions in <code>LOCAL_CPP_EXTENSION</code>. For
example, to compile both <code>foo.cpp</code> and <code>bar.cxx</code> as C++ sources,
declare the following:
<pre>
LOCAL_CPP_EXTENSION := .cpp .cxx
</pre>
</li>
<li>Removed many unwanted exported symbols from the link-time shared system libraries
provided by the NDK. This ensures that code generated with the standalone toolchain
doesn't risk to accidentally depend on a non-stable ABI symbol (e.g. any libgcc.a
symbol that changes each time the toolchain used to build the platform is changed)</li>
<li>Refreshed the EGL and OpenGLES Khronos headers to support more extensions. Note
that this does <em>not</em> change the NDK ABIs for the corresponding libraries,
because each extension must be probed at runtime by the client application.
<p>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
probed with <code>eglGetProcAddress()</code> or <code>glGetProcAddress()</code>. The
following list describes the newly supported extensions:</p>
<dl>
<dt>GLES 1.x</dt>
<dd>
<ul>
<li><code>GL_OES_vertex_array_object</code></li>
<li><code>GL_OES_EGL_image_external</code></li>
<li><code>GL_APPLE_texture_2D_limited_npot</code></li>
<li><code>GL_EXT_blend_minmax</code></li>
<li><code>GL_EXT_discard_framebuffer</code></li>
<li><code>GL_EXT_multi_draw_arrays</code></li>
<li><code>GL_EXT_read_format_bgra</code></li>
<li><code>GL_EXT_texture_filter_anisotropic</code></li>
<li><code>GL_EXT_texture_format_BGRA8888</code></li>
<li><code>GL_EXT_texture_lod_bias</code></li>
<li><code>GL_IMG_read_format</code></li>
<li><code>GL_IMG_texture_compression_pvrtc</code></li>
<li><code>GL_IMG_texture_env_enhanced_fixed_function</code></li>
<li><code>GL_IMG_user_clip_plane</code></li>
<li><code>GL_IMG_multisampled_render_to_texture</code></li>
<li><code>GL_NV_fence</code></li>
<li><code>GL_QCOM_driver_control</code></li>
<li><code>GL_QCOM_extended_get</code></li>
<li><code>GL_QCOM_extended_get2</code></li>
<li><code>GL_QCOM_perfmon_global_mode</code></li>
<li><code>GL_QCOM_writeonly_rendering</code></li>
<li><code>GL_QCOM_tiled_rendering</code></li>
</ul>
</dd>
<dt>GLES 2.0</dt>
<dd>
<ul>
<li><code>GL_OES_element_index_uint</code></li>
<li><code>GL_OES_get_program_binary</code></li>
<li><code>GL_OES_mapbuffer</code></li>
<li><code>GL_OES_packed_depth_stencil</code></li>
<li><code>GL_OES_texture_3D</code></li>
<li><code>GL_OES_texture_float</code></li>
<li><code>GL_OES_texture_float_linear</code></li>
<li><code>GL_OES_texture_half_float_linear</code></li>
<li><code>GL_OES_texture_npot</code></li>
<li><code>GL_OES_vertex_array_object</code></li>
<li><code>GL_OES_EGL_image_external</code></li>
<li><code>GL_AMD_program_binary_Z400</code></li>
<li><code>GL_EXT_blend_minmax</code></li>
<li><code>GL_EXT_discard_framebuffer</code></li>
<li><code>GL_EXT_multi_draw_arrays</code></li>
<li><code>GL_EXT_read_format_bgra</code></li>
<li><code>GL_EXT_texture_format_BGRA8888</code></li>
<li><code>GL_EXT_texture_compression_dxt1</code></li>
<li><code>GL_IMG_program_binary</code></li>
<li><code>GL_IMG_read_format</code></li>
<li><code>GL_IMG_shader_binary</code></li>
<li><code>GL_IMG_texture_compression_pvrtc</code></li>
<li><code>GL_IMG_multisampled_render_to_texture</code></li>
<li><code>GL_NV_coverage_sample</code></li>
<li><code>GL_NV_depth_nonlinear</code></li>
<li><code>GL_QCOM_extended_get</code></li>
<li><code>GL_QCOM_extended_get2</code></li>
<li><code>GL_QCOM_writeonly_rendering</code></li>
<li><code>GL_QCOM_tiled_rendering</code></li>
</ul>
</dd>
<dt>EGL</dt>
<dd>
<ul>
<li><code>EGL_ANDROID_recordable</code></li>
<li><code>EGL_NV_system_time</code></li>
</ul>
</dd>
</dl>
</li>
</ul>
</dd>
</dl>
</div>
</div>
<div class="toggleable closed">
<a href="#" onclick="return toggleDiv(this)"><img src=
"{@docRoot}assets/images/triangle-closed.png" class="toggle-img" height="9px" width="9px">
Android NDK, Revision 6b</a> <em>(August 2011)</em>
<div class="toggleme">
<p>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:</p>
<dl>
<dt>Important bug fixes</dt>
<dd>
<ul>
<li>Fixed the build when <code>APP_ABI="armeabi x86"</code> is used for
multi-architecture builds.</li>
<li>Fixed the location of prebuilt STLport binaries in the NDK release package.
A bug in the packaging script placed them in the wrong location.</li>
<li>Fixed <code>atexit()</code> usage in shared libraries with the x86standalone
toolchain.</li>
<li>Fixed <code>make-standalone-toolchain.sh --arch=x86</code>. It used to fail
to copy the proper GNU libstdc++ binaries to the right location.</li>
<li>Fixed the standalone toolchain linker warnings about missing the definition and
size for the <code>__dso_handle</code> symbol (ARM only).</li>
<li>Fixed the inclusion order of <code>$(SYSROOT)/usr/include</code> for x86 builds.
See the <a href="http://code.google.com/p/android/issues/detail?id=18540">bug</a> for
more information.</li>
<li>Fixed the definitions of <code>ptrdiff_t</code> and <code>size_t</code> in
x86-specific systems when they are used with the x86 standalone toolchain.</li>
</ul>
</dd>
</dl>
</div>
</div>
<div class="toggleable closed">
<a href="#" onclick="return toggleDiv(this)"><img src=
"{@docRoot}assets/images/triangle-closed.png" class="toggle-img" height="9px" width="9px">
Android NDK, Revision 6</a> <em>(July 2011)</em>
<div class="toggleme">
<p>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
<code>CHANGES.HTML</code> document included in the NDK package.
</p>
<dl>
<dt>General notes:</dt>
<dd>
<ul>
<li>Adds support for the x86 ABI, which allows you to generate machine code
that runs on compatible x86-based Android devices. Major features for x86
include x86-specific toolchains, system headers, libraries and
debugging support. For all of the details regarding x86 support,
see <code>docs/CPU-X86.html</code> in the NDK package.
<p>By default, code is generated for ARM-based devices, but you can add x86 to your
<code>APP_ABI</code> definition in your <code>Application.mk</code> file to build
for x86 platforms. For example, the following line instructs <code>ndk-build</code>
to build your code for three distinct ABIs:</p>
<pre>APP_ABI := armeabi armeabi-v7a x86</pre>
<p>Unless you rely on ARM-based assembly sources, you shouldn't need to touch
your <code>Android.mk</code> files to build x86 machine code.</p>
</li>
<li>You can build a standalone x86 toolchain using the <code>--toolchain=x86-4.4.3</code>
option when calling <code>make-standalone-toolchain.sh</code>. See
<code>docs/STANDALONE-TOOLCHAIN.html</code> for more details.
</li>
<li>The new <code>ndk-stack</code> tool lets you translate stack traces in
<code>logcat</code> that 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 <code>docs/NDK-STACK.html</code>.
</li>
</ul>
</dd>
<dt>Other changes:</dt>
<dd><code>arm-eabi-4.4.0</code>, which had been deprecated since NDK r5, has been
removed from the NDK distribution.</dd>
</dl>
</div>
</div>
<div class="toggleable closed">
<a href="#" onclick="return toggleDiv(this)"><img src=
"{@docRoot}assets/images/triangle-closed.png" class="toggle-img" height="9px" width="9px">
Android NDK, Revision 5c</a> <em>(June 2011)</em>
<div class="toggleme">
<p>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:</p>
<dl>
<dt>Important bug fixes:</dt>
<dd>
<ul>
<li><code>ndk-build</code>: Fixed a rare bug that appeared when trying to perform parallel
builds of debuggable projects.</li>
<li>Fixed a typo that prevented <code>LOCAL_WHOLE_STATIC_LIBRARIES</code> to work
correctly with the new toolchain and added documentation for this in
<code>docs/ANDROID-MK.html</code>.</li>
<li>Fixed a bug where code linked against <code>gnustl_static</code> crashed when run on
platform releases older than API level 8 (Android 2.2).</li>
<li><code>ndk-gdb</code>: Fixed a bug that caused a segmentation fault when debugging Android 3.0
or newer devices.</li>
<li><code>&lt;android/input.h&gt;</code>: 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
<code>history_index</code> parameter, and the correct definitions are shown below:
<pre>
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);
</pre>
</li>
<li>Updated the C library ARM binary for API level 9 (Android 2.3) to correctly expose at
link time new functions that were added in that API level (for example,
<code>pthread_rwlock_init</code>).</li>
</ul>
</dd>
<dt>Minor improvements and fixes:</dt>
<dd>
<ul>
<li>Object files are now always linked in the order they appear in
<code>LOCAL_SRC_FILES</code>. This was not the case previously because the files were
grouped by source extensions instead.</li>
<li>When <code>import-module</code> fails, it now prints the list of directories that
were searched. This is useful to check that the <code>NDK_MODULE_PATH</code> definition
used by the build system is correct.</li>
<li>When <code>import-module</code> succeeds, it now prints the directory where the
module was found to the log (visible with <code>NDK_LOG=1</code>).</li>
<li>Increased the build speed of debuggable applications when there is a very large number
of include directories in the project.</li>
<li><code>ndk-gdb</code>: Better detection of <code>adb shell</code> failures and improved
error messages.</li>
<li><code>&lt;pthread.h&gt;</code>: Fixed the definition of
<code>PTHREAD_RWLOCK_INITIALIZER</code> for API level 9 (Android 2.3) and higher.</li>
<li>Fixed an issue where a module could import itself, resulting in an infinite loop in
GNU Make.</li>
<li>Fixed a bug that caused the build to fail if <code>LOCAL_ARM_NEON</code> was set to
true (typo in <code>build/core/build-binary.mk</code>).</li>
<li>Fixed a bug that prevented the compilation of </code>.s</code> assembly files
(<code>.S</code> files were okay).</li>
</ul>
</dd>
</div>
</div>
<div class="toggleable closed">
<a href="#"
onclick="return toggleDiv(this)"><img src="{@docRoot}assets/images/triangle-closed.png"
class="toggle-img"
height="9px"
width="9px" /> Android NDK, Revision 5b</a> <em>(January 2011)</em>
<div class="toggleme">
<p>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:
</p>
<ul>
<li>The r5 binaries required glibc 2.11, but the r5b binaries are generated with a special
toolchain that targets glibc 2.7 or higher instead. The Linux toolchain binaries now run on Ubuntu 8.04 or higher. </li>
<li>Fixes a compiler bug in the arm-linux-androideabi-4.4.3 toolchain.
The previous binary generated invalid thumb instruction sequences when
dealing with signed chars.</li>
<li>Adds missing documentation for the
"gnustl_static" value for APP_STL, that allows you to link against
a static library version of GNU libstdc++. </li>
<li>The following <code>ndk-build</code> issues are fixed:
<ul>
<li>A bug that created inconsistent dependency files when a
compilation error occured on Windows. This prevented a proper build after
the error was fixed in the source code.</li>
<li>A Cygwin-specific bug where using very short paths for
the Android NDK installation or the project path led to the
generation of invalid dependency files. This made incremental builds
impossible.</li>
<li>A typo that prevented the cpufeatures library from working correctly
with the new NDK toolchain.</li>
<li>Builds in Cygwin are faster by avoiding calls to <code>cygpath -m</code>
from GNU Make for every source or object file, which caused problems
with very large source trees. In case this doesn't work properly, define <code>NDK_USE_CYGPATH=1</code> in your
environment to use <code>cygpath -m</code> again.</li>
<li>The Cygwin installation now notifies the user of invalid installation paths that contain spaces. Previously, an invalid path
would output an error that complained about an incorrect version of GNU Make, even if the right one was installed.
</ul>
</li>
<li>Fixed a typo that prevented the <code>NDK_MODULE_PATH</code> environment variable from working properly when
it contained multiple directories separated with a colon. </li>
<li>The <code>prebuilt-common.sh</code> script 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.</li>
<li>A missing declaration for <code>INET_ADDRSTRLEN</code> was added to <code>&lt;netinet/in.h&gt;</code>.</li>
<li>Missing declarations for <code>IN6_IS_ADDR_MC_NODELOCAL</code> and <code>IN6_IS_ADDR_MC_GLOBAL</code> were added to <code>&lt;netinet/in6.h&gt;</code>.</li>
<li>'asm' was replaced with '__asm__' in <code>&lt;asm/byteorder.h&gt;</code> to allow compilation with <code>-std=c99</code>.</li>
</ul>
</div>
</div>
<div class="toggleable closed">
<a href="#"
onclick="return toggleDiv(this)"><img src="{@docRoot}assets/images/triangle-closed.png"
class="toggle-img"
height="9px"
width="9px" /> Android NDK, Revision 5</a> <em>(December 2010)</em>
<div class="toggleme">
<p>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
{@link android.app.NativeActivity} class. For detailed information describing the changes in this
release, read the <code>CHANGES.HTML</code> document included in the downloaded NDK package.
</p>
<dl>
<dt>General notes:</dt>
<dd>
<ul>
<li>Adds support for native activities, which allows you to implement the
Android application lifecycle in native code.</li>
<li>Adds native support for the following:
<ul>
<li>Input subsystem (such as the keyboard and touch screen)</li>
<li>Access to sensor data (accelerometer, compass, gyroscope, etc).</li>
<li>Event loop APIs to wait for things such as input and sensor events.</li>
<li>Window and surface subsystem</li>
<li>Audio APIs based on the OpenSL ES standard that support playback and recording
as well as control over platform audio effects</li>
<li>Access to assets packaged in an <code>.apk</code> file.</li>
</ul>
</li>
<li>Includes a new toolchain (based on GCC 4.4.3), which generates better code, and can also now
be used as a standalone cross-compiler, for people who want to build their stuff with
<code>./configure &amp;&amp; make</code>. 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.</li>
<li>Adds support for prebuilt static and shared libraries (docs/PREBUILTS.html) and module
exports and imports to make sharing and reuse of third-party modules much easier
(docs/IMPORT-MODULE.html explains why).</li>
<li>Provides a default C++ STL implementation (based on STLport) as a helper module. It can be used either
as a static or shared library (details and usage examples are in sources/android/stlport/README). Prebuilt
binaries for STLport (static or shared) and GNU libstdc++ (static only) are also provided if you choose to
compile against those libraries instead of the default C++ STL implementation.
C++ Exceptions and RTTI are not supported in the default STL implementation. For more information, see
docs/CPLUSPLUS-SUPPORT.HTML.</li>
<li>Includes improvements to the <code>cpufeatures</code> helper 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.</li>
<li>Adds an EGL library that lets you create and manage OpenGL ES textures and
services.</li>
<li>Adds new sample applications, <code>native-plasma</code> and <code>native-activity</code>,
to demonstrate how to write a native activity.</li>
<li>Includes many bugfixes and other small improvements; see docs/CHANGES.html for a more
detailed list of changes.</li>
</ul>
</dd>
</dl>
</div>
</div>
<div class="toggleable closed">
<a href="#"
onclick="return toggleDiv(this)"><img src="{@docRoot}assets/images/triangle-closed.png"
class="toggle-img"
height="9px"
width="9px" /> Android NDK, Revision 4b</a> <em>(June 2010)</em>
<div class="toggleme">
<dl>
<dt>NDK r4b notes:</dt>
<dd>
<p>Includes fixes for several issues in the NDK build and debugging scripts &mdash; 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.</p>
</dd>
</dl>
<dl>
<dt>General notes:</dt>
<dd>
<ul>
<li>Provides a simplified build system through the new <code>ndk-build</code> build
command.</li>
<li>Adds support for easy native debugging of generated machine code on production
devices through the new <code>ndk-gdb</code> command.</li>
<li>Adds a new Android-specific ABI for ARM-based CPU architectures,
<code>armeabi-v7a</code>. The new ABI extends the existing <code>armeabi</code> ABI to
include these CPU instruction set extensions:
<ul>
<li>Thumb-2 instructions</li>
<li>VFP hardware FPU instructions (VFPv3-D16)</li>
<li>Optional support for ARM Advanced SIMD (NEON) GCC intrinsics and VFPv3-D32.
Supported by devices such as Verizon Droid by Motorola, Google Nexus One, and
others.</li>
</ul>
</li>
<li>Adds a new <code>cpufeatures</code> static 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.</li>
<li>Adds a sample application, <code>hello-neon</code>, that illustrates how to use the
<code>cpufeatures</code> library to check CPU features and then provide an optimized
code path using NEON instrinsics, if supported by the CPU.</li>
<li>Lets you generate machine code for either or both of the instruction sets supported
by the NDK. For example, you can build for both ARMv5 and ARMv7-A architectures at the
same time and have everything stored to your application's final
<code>.apk</code>.</li>
<li>To ensure that your applications are available to users only if their devices are
capable of running them, Google Play now filters applications based on the
instruction set information included in your application &mdash; 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.</li>
<li>Adds support for Android 2.2, including a new stable API for accessing the pixel
buffers of {@link android.graphics.Bitmap} objects from native code.</li>
</ul>
</dd>
</dl>
</div>
</div>
<div class="toggleable closed">
<a href="#"
onclick="return toggleDiv(this)"><img src="{@docRoot}assets/images/triangle-closed.png"
class="toggle-img"
height="9px"
width="9px" /> Android NDK, Revision 3</a> <em>(March 2010)</em>
<div class="toggleme">
<dl>
<dt>General notes:</dt>
<dd>
<ul>
<li>Adds OpenGL ES 2.0 native library support.</li>
<li>Adds a sample application,<code>hello-gl2</code>, that illustrates the use of
OpenGL ES 2.0 vertex and fragment shaders.</li>
<li>The toolchain binaries have been refreshed for this release with GCC 4.4.0, which
should generate slightly more compact and efficient machine code than the previous one
(4.2.1). The NDK also still provides the 4.2.1 binaries, which you can optionally use
to build your machine code.</li>
</ul>
</dd>
</dl>
</div>
</div>
<div class="toggleable closed">
<a href="#"
onclick="return toggleDiv(this)"><img src="{@docRoot}assets/images/triangle-closed.png"
class="toggle-img"
height="9px"
width="9px" /> Android NDK, Revision 2</a> <em>(September 2009)</em>
<div class="toggleme">
<p>Originally released as "Android 1.6 NDK, Release 1".</p>
<dl>
<dt>General notes:</dt>
<dd>
<ul>
<li>Adds OpenGL ES 1.1 native library support.</li>
<li>Adds a sample application, <code>san-angeles</code>, that renders 3D graphics
through the native OpenGL ES APIs, while managing activity lifecycle with a {@link
android.opengl.GLSurfaceView} object.</li>
</ul>
</dd>
</dl>
</div>
</div>
<div class="toggleable closed">
<a href="#"
onclick="return toggleDiv(this)"><img src="{@docRoot}assets/images/triangle-closed.png"
class="toggle-img"
height="9px"
width="9px" /> Android NDK, Revision 1</a> <em>(June 2009)</em>
<div class="toggleme">
<p>Originally released as "Android 1.5 NDK, Release 1".</p>
<dl>
<dt>General notes:</dt>
<dd>
<ul>
<li>Includes compiler support (GCC) for ARMv5TE instructions, including Thumb-1
instructions.</li>
<li>Includes system headers for stable native APIs, documentation, and sample
applications.</li>
</ul>
</dd>
</dl>
</div>
</div>
<!-- ####################### END OF RELEASE NOTES ####################### -->
<h2 id="Reqs">System and Software Requirements</h2>
<p>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.</p>
<h4>The Android SDK</h4>
<ul>
<li>A complete Android SDK installation (including all dependencies) is required.</li>
<li>Android 1.5 SDK or later version is required.</li>
</ul>
<h4>Supported operating systems</h4>
<ul>
<li>Windows XP (32-bit) or Vista (32- or 64-bit)</li>
<li>Mac OS X 10.4.8 or later (x86 only)</li>
<li>Linux (32 or 64-bit; Ubuntu 8.04, or other Linux distributions using GLibc 2.7 or
later)</li>
</ul>
<h4>Required development tools</h4>
<ul>
<li>For all development platforms, GNU Make 3.81 or later is required. Earlier versions of GNU
Make might work but have not been tested.</li>
<li>A recent version of awk (either GNU Awk or Nawk) is also required.</li>
<li>For Windows, <a href="http://www.cygwin.com">Cygwin</a> 1.7 or higher is required. The NDK
will <em>not</em> work with Cygwin 1.5 installations.</li>
</ul>
<h4 id="platform-compat">Android platform compatibility</h4>
<ul>
<li>The native libraries created by the Android NDK can only be used on devices running
specific minimum Android platform versions. The minimum required platform version depends on
the CPU architecture of the devices you are targeting. The following table details which
Android platform versions are compatible with native code developed for specific CPU
architectures.
<table style="margin:1em;">
<tr>
<th>Native Code CPU Architecture Used</th>
<th>Compatible Android Platform(s)</th>
</tr>
<tr>
<td>ARM, ARM-NEON</td>
<td>Android 1.5 (API Level 3) and higher</td>
</tr>
<tr>
<td>x86</td>
<td>Android 2.3 (API Level 9) and higher</td>
</tr>
<tr>
<td>MIPS</td>
<td>Android 2.3 (API Level 9) and higher</td>
</tr>
</table>
<p>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.</p>
</li>
<li>To ensure compatibility, an application using a native library produced with the NDK
<em>must</em> declare a <a href="{@docRoot}guide/topics/manifest/uses-sdk-element.html"><code>
&lt;uses-sdk&gt;</code></a> element in its manifest file, with an
<code>android:minSdkVersion</code> attribute value of "3" or higher. For example:
<pre style="margin:1em;">
&lt;manifest&gt;
&lt;uses-sdk android:minSdkVersion="3" /&gt;
...
&lt;/manifest&gt;
</pre>
</li>
<li>If you use this NDK to create a native library that uses the OpenGL ES APIs, the
application containing the library can be deployed only to devices running the minimum platform
versions described in the table below. To ensure compatibility, make sure that your application
declares the proper <code>android:minSdkVersion</code> attribute value, as shown in the
following table.</li>
<li style="list-style: none; display: inline">
<table style="margin:1em;">
<tr>
<th>OpenGL ES Version Used</th>
<th>Compatible Android Platform(s)</th>
<th>Required uses-sdk Attribute</th>
</tr>
<tr>
<td>OpenGL ES 1.1</td>
<td>Android 1.6 (API Level 4) and higher</td>
<td><code>android:minSdkVersion="4"</code></td>
</tr>
<tr>
<td>OpenGL ES 2.0</td>
<td>Android 2.0 (API Level 5) and higher</td>
<td><code>android:minSdkVersion="5"</code></td>
</tr>
</table>
<p>For more information about API Level and its relationship to Android platform versions,
see <a href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#ApiLevels">Android API Levels</a>.</p>
</li>
<li>Additionally, an application using the OpenGL ES APIs should declare a
<code>&lt;uses-feature&gt;</code> element in its manifest, with an
<code>android:glEsVersion</code> attribute 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:
<pre style="margin:1em;">
&lt;manifest&gt;
<!-- Declare that the application uses the OpenGL ES 2.0 API and is designed
to run only on devices that support OpenGL ES 2.0 or higher. -->
&lt;uses-feature android:glEsVersion="0x00020000" /&gt;
...
&lt;/manifest&gt;
</pre>
<p>For more information, see the <a href=
"{@docRoot}guide/topics/manifest/uses-feature-element.html"><code>&lt;uses-feature&gt;</code></a>
documentation.</p>
</li>
<li>If you use this NDK to create a native library that uses the API to access Android {@link
android.graphics.Bitmap} pixel 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 <code>&lt;uses-sdk
android:minSdkVersion="8" /&gt;</code> attribute value in its manifest.</li>
</ul>
<h2 id="Installing">Installing the NDK</h2>
<p>Installing the NDK on your development computer is straightforward and involves extracting the
NDK from its download package.</p>
<p>Before you get started make sure that you have downloaded the latest <a href=
"{@docRoot}sdk/index.html">Android SDK</a> 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 <a href="{@docRoot}tools/sdk/ndk/overview.html#reqs">System and
Software Requirements</a>
for the NDK, if you haven't already.</p>
<p>To install the NDK, follow these steps:</p>
<ol>
<li>From the table at the top of this page, select the NDK package that is appropriate for your
development computer and download the package.</li>
<li>Uncompress the NDK download package using tools available on your computer. When
uncompressed, the NDK files are contained in a directory called
<code>android-ndk-&lt;version&gt;</code>. 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
<code>&lt;ndk&gt;</code>.</li>
</ol>
<p>You are now ready to start working with the NDK.</p>
<h2 id="GetStarted">Getting Started with the NDK</h2>
<p>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 <code>&lt;ndk&gt;/docs/</code>
directory. In particular, please read the OVERVIEW.HTML document completely, so that you
understand the intent of the NDK and how to use it.</p>
<p>If you used a previous version of the NDK, take a moment to review the list of NDK changes in
the CHANGES.HTML document.</p>
<p>Here's the general outline of how you work with the NDK tools:</p>
<ol>
<li>Place your native sources under <code>&lt;project&gt;/jni/...</code></li>
<li>Create <code>&lt;project&gt;/jni/Android.mk</code> to describe your native sources to the
NDK build system</li>
<li>Optional: Create <code>&lt;project&gt;/jni/Application.mk</code>.</li>
<li>Build your native code by running the 'ndk-build' script from your project's directory. It
is located in the top-level NDK directory:
<pre class="no-pretty-print">cd &lt;project&gt;
&lt;ndk&gt;/ndk-build
</pre>
<p>The build tools copy the stripped, shared libraries needed by your application to the
proper location in the application's project directory.</p>
</li>
<li>Finally, compile your application using the SDK tools in the usual way. The SDK build tools
will package the shared libraries in the application's deployable <code>.apk</code> file.</li>
</ol>
<p>For complete information on all of the steps listed above, please see the documentation
included with the NDK package.</p>
<h3 id="Using">Using the NDK</h3>
<p>The Android framework provides two ways to use native code:</p>
<ul>
<li>Write your application using the Android framework and use JNI to access the APIs provided
by the Android NDK. This technique allows you to take advantage of the convenience of the
Android framework, but still allows you to write native code when necessary. If you use this
approach, your application must target specific, minimum Android platform levels, see <a
href="#platform-compat">Android platform compatibility</a> for more information.</li>
<li>
<p>Write a native activity, which allows you to implement the lifecycle callbacks in native
code. The Android SDK provides the {@link android.app.NativeActivity} class, which is a
convenience class that notifies your
native code of any activity lifecycle callbacks (<code>onCreate()</code>, <code>onPause()</code>,
<code>onResume()</code>, 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.</p>
<p>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.</p>
</li>
</ul>
<h2 id="Contents">Contents of the NDK</h2>
<p>The NDK contains the APIs, documentation, and sample
applications that help you write your native code. Specifically:</p>
<ul>
<li>A set of tools and build files used to generate native code libraries from C and C++
sources</li>
<li>A way to embed the corresponding native libraries into an application package file
(<code>.apk</code>) that can be deployed on Android devices</li>
<li>A set of native system headers and libraries that will be supported in all future versions
of the Android platform, starting from Android 1.5. Applications that use native activities
must be run on Android 2.3 or later.</li>
<li>Documentation, samples, and tutorials</li>
</ul>
<p>The latest release of the NDK supports the following instruction sets:</p>
<ul>
<li>ARMv5TE, including Thumb-1 instructions (see {@code docs/CPU-ARCH-ABIS.html} for more
information)</li>
<li>ARMv7-A, including Thumb-2 and VFPv3-D16 instructions, with optional support for
NEON/VFPv3-D32 instructions (see {@code docs/CPU-ARM-NEON.html} for more information)</li>
<li>x86 instructions (see {@code docs/CPU-X86.html} for more information)</li>
<li>MIPS instructions (see {@code docs/CPU-MIPS.html} for more information)</li>
</ul>
<p>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 &mdash; ARMv5TE is the
default, but switching to ARMv7-A is as easy as adding a single line to the application's
<code>Application.mk</code> 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 <code>.apk</code>.
Complete information is provided in the CPU-ARCH-ABIS.HTML in the NDK package.</p>
<p>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 <a href=
"#Tools">Development tools</a> section.</p>
<h3 id="Tools">Development tools</h3>
<p>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.</p>
<p>It provides a set of system headers for stable native APIs that are guaranteed to be supported
in all later releases of the platform:</p>
<ul>
<li>libc (C library) headers</li>
<li>libm (math library) headers</li>
<li>JNI interface headers</li>
<li>libz (Zlib compression) headers</li>
<li>liblog (Android logging) header</li>
<li>OpenGL ES 1.1 and OpenGL ES 2.0 (3D graphics libraries) headers</li>
<li>libjnigraphics (Pixel buffer access) header (for Android 2.2 and above).</li>
<li>A Minimal set of headers for C++ support</li>
<li>OpenSL ES native audio libraries</li>
<li>Android native application APIS</li>
</ul>
<p>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 &mdash; the build
system compiles the sources and places the shared libraries directly in your application
project.</p>
<p class="caution"><strong>Important:</strong> With the exception of the libraries listed above,
native system libraries in the Android platform are <em>not</em> stable and may change in future
platform versions. Your applications should <em>only</em> make use of the stable native system
libraries provided in this NDK.</p>
<h3 id="Docs">Documentation</h3>
<p>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
the <code>&lt;ndk&gt;/docs/</code> directory. Included are these files (partial listing):</p>
<ul>
<li>
INSTALL.HTML &mdash; describes how to install the NDK and configure it for your host
system</li>
<li>OVERVIEW.HTML &mdash; provides an overview of the NDK capabilities and usage</li>
<li>ANDROID-MK.HTML &mdash; describes the use of the Android.mk file, which defines the native
sources you want to compile</li>
<li>APPLICATION-MK.HTML &mdash; describes the use of the Application.mk file, which describes
the native sources required by your Android application</li>
<li>CPLUSPLUS-SUPPORT.HTML &mdash; describes the C++ support provided in the Android NDK</li>
<li>CPU-ARCH-ABIS.HTML &mdash; a description of supported CPU architectures and how to target
them.</li>
<li>CPU-FEATURES.HTML &mdash; a description of the <code>cpufeatures</code> static library that
lets your application code detect the target device's CPU family and the optional features at
runtime.</li>
<li>CHANGES.HTML &mdash; a complete list of changes to the NDK across all releases.</li>
<li>DEVELOPMENT.HTML &mdash; describes how to modify the NDK and generate release packages for it</li>
<li>HOWTO.HTML &mdash; information about common tasks associated with NDK development</li>
<li>IMPORT-MODULE.HTML &mdash; describes how to share and reuse modules</li>
<li>LICENSES.HTML &mdash; information about the various open source licenses that govern the Android NDK</li>
<li>NATIVE-ACTIVITY.HTML &mdash; describes how to implement native activities</li>
<li>NDK-BUILD.HTML &mdash; describes the usage of the ndk-build script</li>
<li>NDK-GDB.HTML &mdash; describes how to use the native code debugger</li>
<li>PREBUILTS.HTML &mdash; information about how shared and static prebuilt libraries work </li>
<li>STANDALONE-TOOLCHAIN.HTML &mdash; describes how to use Android NDK toolchain as a standalone
compiler (still in beta).</li>
<li>SYSTEM-ISSUES.HTML &mdash; known issues in the Android system images that you should be
aware of, if you are developing using the NDK.</li>
<li>STABLE-APIS.HTML &mdash; a complete list of the stable APIs exposed by headers in the
NDK.</li>
</ul>
<p>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 <code>&lt;ndk&gt;/docs/system/libc/</code> directory:</p>
<ul>
<li>OVERVIEW.HTML &mdash; provides an overview of the "bionic" C library and the features it
offers.</li>
</ul>
<h3 id="Samples">Sample apps</h3>
<p>The NDK includes sample applications that illustrate how to use native code in your Android
applications:</p>
<ul>
<li><code>hello-jni</code> &mdash; a simple application that loads a string from a native
method implemented in a shared library and then displays it in the application UI.</li>
<li><code>two-libs</code> &mdash; 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.</li>
<li><code>san-angeles</code> &mdash; a simple application that renders 3D graphics through the
native OpenGL ES APIs, while managing activity lifecycle with a {@link
android.opengl.GLSurfaceView} object.</li>
<li><code>hello-gl2</code> &mdash; a simple application that renders a triangle using OpenGL ES
2.0 vertex and fragment shaders.</li>
<li><code>hello-neon</code> &mdash; a simple application that shows how to use the
<code>cpufeatures</code> library 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.</li>
<li><code>bitmap-plasma</code> &mdash; a simple application that demonstrates how to access the
pixel buffers of Android {@link android.graphics.Bitmap} objects from native code, and uses
this to generate an old-school "plasma" effect.</li>
<li><code>native-activity</code> &mdash; a simple application that demonstrates how to use the
native-app-glue static library to create a native activity</li>
<li><code>native-plasma</code> &mdash; a version of bitmap-plasma implemented with a native
activity.</li>
</ul>
<p>For each sample, the NDK includes the corresponding C source code and the necessary Android.mk
and Application.mk files. There are located under <code>&lt;ndk&gt;/samples/&lt;name&gt;/</code>
and their source code can be found under <code>&lt;ndk&gt;/samples/&lt;name&gt;/jni/</code>.</p>
<p>You can build the shared libraries for the sample apps by going into
<code>&lt;ndk&gt;/samples/&lt;name&gt;/</code> then calling the <code>ndk-build</code> command.
The generated shared libraries will be located under
<code>&lt;ndk&gt;/samples/&lt;name&gt;/libs/armeabi/</code> for (ARMv5TE machine code) and/or
<code>&lt;ndk&gt;/samples/&lt;name&gt;/libs/armeabi-v7a/</code> for (ARMv7 machine code).</p>
<p>Next, build the sample Android applications that use the shared libraries:</p>
<ul>
<li>If you are developing in Eclipse with ADT, use the New Project Wizard to create a new
Android project for each sample, using the "Import from Existing Source" option and importing
the source from <code>&lt;ndk&gt;/samples/&lt;name&gt;/</code>. Then, set up an AVD,
if necessary, and build/run the application in the emulator.</li>
<li>If you are developing with Ant, use the <code>android</code> tool to create the build file
for each of the sample projects at <code>&lt;ndk&gt;/samples/&lt;name&gt;/</code>.
Then set up an AVD, if necessary, build your project in the usual way, and run it in the
emulator.</li>
</ul>
<p>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 <a href="{@docRoot}tools/workflow/index.html">Overview</a>
section for developing on Android.</p>
<h4 id="hello-jni">Exploring the hello-jni Sample</h4>
<p>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.</p>
<p>The main components of the sample include:</p>
<ul>
<li>The familiar basic structure of an Android application (an <code>AndroidManifest.xml</code>
file, a <code>src/</code> and <code>res</code> directories, and a main activity)</li>
<li>A <code>jni/</code> directory that includes the implemented source file for the native code
as well as the Android.mk file</li>
<li>A <code>tests/</code> directory that contains unit test code.</li>
</ul>
<ol>
<li>Create a new project in Eclipse from the existing sample source or use the
<code>android</code> tool to update the project so it generates a build.xml file that you can
use to build the sample.
<ul>
<li>In Eclipse:
<ol type="a">
<li>Click <strong>File &gt; New Android Project...</strong></li>
<li>Select the <strong>Create project from existing source</strong> radio button.</li>
<li>Select any API level above Android 1.5.</li>
<li>In the <strong>Location</strong> field, click <strong>Browse...</strong> and select
the <code>&lt;ndk-root&gt;/samples/hello-jni</code> directory.</li>
<li>Click <strong>Finish</strong>.</li>
</ol>
</li>
<li>On the command line:
<ol type="a">
<li>Change to the <code>&lt;ndk-root&gt;/samples/hello-jni</code> directory.</li>
<li>Run the following command to generate a build.xml file:
<pre class="no-pretty-print">android update project -p . -s</pre>
</li>
</ol>
</li>
</ul>
</li>
<li>Compile the native code using the <code>ndk-build</code> command.
<pre class="no-pretty-print">
cd &lt;ndk-root&gt;/samples/hello-jni
&lt;ndk_root&gt;/ndk-build
</pre>
</li>
<li>Build and install the application as you would a normal Android application. If you are
using Eclipse, run the application to build and install it on a device. If you are using Ant,
run the following commands from the project directory:
<pre class="no-pretty-print">
ant debug
adb install bin/HelloJni-debug.apk
</pre>
</li>
</ol>
<p>When you run the application on the device, the string <code>Hello JNI</code> should appear on
your device. You can explore the rest of the samples that are located in the
<code>&lt;ndk-root&gt;/samples</code> directory for more examples on how to use the JNI.</p>
<h4 id="native-activity">Exploring the native-activity Sample Application</h4>
<p>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:</p>
<ul>
<li>The familiar basic structure of an Android application (an <code>AndroidManifest.xml</code>
file, a <code>src/</code> and <code>res</code> directories). The AndroidManifest.xml declares
that the application is native and specifies the .so file of the native activity. See {@link
android.app.NativeActivity} for the source or see the
<code>&lt;ndk_root&gt;/platforms/samples/native-activity/AndroidManifest.xml</code> file.</li>
<li>A <code>jni/</code> directory contains the native activity, main.c, which uses the
<code>android_native_app_glue.h</code> interface to implement the activity. The Android.mk that
describes the native module to the build system also exists here.</li>
</ul>
<p>To build this sample application:</p>
<ol>
<li>Create a new project in Eclipse from the existing sample source or use the
<code>android</code> tool to update the project so it generates a build.xml file that you can
use to build the sample.
<ul>
<li>In Eclipse:
<ol type="a">
<li>Click <strong>File &gt; New Android Project...</strong></li>
<li>Select the <strong>Create project from existing source</strong> radio button.</li>
<li>Select any API level above Android 2.3.</li>
<li>In the <strong>Location</strong> field, click <strong>Browse...</strong> and select
the <code>&lt;ndk-root&gt;/samples/native-activity</code> directory.</li>
<li>Click <strong>Finish</strong>.</li>
</ol>
</li>
<li>On the command line:
<ol type="a">
<li>Change to the <code>&lt;ndk-root&gt;/samples/native-activity</code> directory.</li>
<li>Run the following command to generate a build.xml file:
<pre class="no-pretty-print">
android update project -p . -s
</pre>
</li>
</ol>
</li>
</ul>
</li>
<li>Compile the native code using the <code>ndk-build</code> command.
<pre class="no-pretty-print">
cd &lt;ndk-root&gt;/platforms/samples/android-9/samples/native-activity
&lt;ndk_root&gt;/ndk-build
</pre>
</li>
<li>Build and install the application as you would a normal Android application. If you are
using Eclipse, run the application to build and install it on a device. If you are using Ant,
run the following commands in the project directory, then run the application on the device:
<pre class="no-pretty-print">
ant debug
adb install bin/NativeActivity-debug.apk
</pre>
</li>
</ol>
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