android_frameworks_base/docs/html/sdk/ndk/index.jd

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page.title=Android NDK
@jd:body

<h2 id="notes">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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<div class="toggleable open">
    <a href="#"
         onclick="return toggleDiv(this)"><img src="{@docRoot}assets/images/triangle-opened.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 CHANGES.HTML 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 Market 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, Android Market 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>
  
  <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}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="gettingstarted">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>

  <h2 id="samples">Sample Applications</h2>

  <p>The NDK includes sample Android applications that illustrate how to use native code in your
  Android applications. For more information, see <a href=
  "{@docRoot}sdk/ndk/overview.html#samples">Sample Applications</a>.</p>

  <h2 id="forum">Discussion Forum and Mailing List</h2>

  <p>If you have questions about the NDK or would like to read or contribute to discussions about
  it, please visit the <a href="http://groups.google.com/group/android-ndk">android-ndk</a> group
  and mailing list.</p>