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author | Dirk Dougherty <nobody@android.com> | 2009-06-24 11:01:05 -0700 |
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committer | The Android Open Source Project <initial-contribution@android.com> | 2009-06-24 11:01:05 -0700 |
commit | aea6c2df939eb904d7e4e94d1f538ee91ec451b7 (patch) | |
tree | 2f2b96023235a2e51f5e139ba0fd8292b35c8470 /docs/html/sdk/ndk/1.5_r1 | |
parent | 124d75618b63975a890deab06a0265c601e53b45 (diff) | |
download | frameworks_base-aea6c2df939eb904d7e4e94d1f538ee91ec451b7.zip frameworks_base-aea6c2df939eb904d7e4e94d1f538ee91ec451b7.tar.gz frameworks_base-aea6c2df939eb904d7e4e94d1f538ee91ec451b7.tar.bz2 |
AI 150083: Minor updates to the ndk docs based on approved messaging.
BUG=1790234
Automated import of CL 150083
Diffstat (limited to 'docs/html/sdk/ndk/1.5_r1')
-rw-r--r-- | docs/html/sdk/ndk/1.5_r1/index.jd | 336 |
1 files changed, 336 insertions, 0 deletions
diff --git a/docs/html/sdk/ndk/1.5_r1/index.jd b/docs/html/sdk/ndk/1.5_r1/index.jd new file mode 100644 index 0000000..48794c0 --- /dev/null +++ b/docs/html/sdk/ndk/1.5_r1/index.jd @@ -0,0 +1,336 @@ +ndk=true +ndk.version=1.5 +ndk.rel.id=1 +ndk.date=June 2009 + +ndk.win_download=android-ndk-1.5_r1-windows.zip +ndk.win_bytes=22500667 +ndk.win_checksum=e5c53915903d8b81f3e2ea422e2e2717 + +ndk.mac_download=android-ndk-1.5_r1-darwin-x86.zip +ndk.mac_bytes=17215303 +ndk.mac_checksum=1931f0e182798a4c98924fd87380b5b8 + +ndk.linux_download=android-ndk-1.5_r1-linux-x86.zip +ndk.linux_bytes=16025885 +ndk.linux_checksum=80a4e14704ca84c21bf1824cb25fbd8b + +page.title=Android 1.5 NDK, Release 1 +@jd:body + +<h2 id="overview">What is the Android NDK?</h2> + +<p>The Android NDK provides tools that allow Android application developers +to embed components that make use of native code in their Android applications. +</p> + +<p>Android applications run in the Dalvik virtual machine. The NDK allows +developers to implement parts of their applications using native-code languages +such as C and C++. This can provide benefits to certain classes of applications, +in the form of reuse of existing code and in some cases increased speed.</p> + +<p>The NDK provides:</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 application package +files (.apks) 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 </li> +<li>Documentation, samples, and tutorials</li> +</ul> + +<p>This release of the NDK supports the ARMv5TE machine instruction set +and provides stable headers for libc (the C library), libm (the Math library), +the JNI interface, and other libraries.</p> + +<p>The NDK will not benefit most applications. As a developer, you will need +to balance its benefits against its drawbacks; notably, using native code does +not result in an automatic performance increase, but does always increase +application complexity. 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. Simply re-coding a method to run in C usually does +not result in a large performance increase. The NDK can, however, can be +an effective way to reuse a large corpus of existing C/C++ code.</p> + +<p>Please note that the NDK <em>does not</em> enable you to develop native-only +applications. Android's primary runtime remains the Dalvik virtual machine.</p> + +<h2 id="contents">Contents of the NDK</h2> + +<h4>Development tools</h4> + +<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>A Minimal set of headers for C++ support</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 — 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 1.5 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> + +<h4>Documentation</h4> + +<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><ndk>/docs/</code> directory. Included are these files:</p> + +<ul> +<li>INSTALL.TXT — describes how to install the NDK and configure it for +your host system</li> +<li>OVERVIEW.TXT — provides an overview of the NDK capabilities and +usage</li> +<li>ANDROID-MK.TXT — describes the use of the Android.mk file, which +defines the native sources you want to compile</li> +<li>APPLICATION-MK.TXT — describes the use of the Application.mk file, +which describes the native sources required by your Android application</li> +<li>HOWTO.TXT — information about common tasks associated with NDK +development.</li> +<li>SYSTEM-ISSUES.TXT — known issues in the Android system images +that you should be aware of, if you are developing using the NDK. </li> +<li>STABLE-APIS.TXT — 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><ndk>/docs/system/libc/</code> directory:</p> + +<ul> +<li>OVERVIEW.TXT — provides an overview of the "bionic" C library and the +features it offers.</li> +</ul> + +<h4>Sample applications</h4> + +<p>The NDK includes two sample Android applications that illustrate how to use +native code in your Android applications:</p> + +<ul> +<li><code>hello-jni</code> — 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> — 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 that is imported by the +shared library. </li> +</ul> + +<p>For more information, see <a href="#samples">Using the Sample +Applications</a>.</p> + +<h2 id="requirements">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, tested on Linux Ubuntu Dapper Drake)</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>For Windows, a recent release of <a +href="http://www.cygwin.com">Cygwin</a> is required.</li> +</ul> + +<h4>Android platform compatibility</h4> +<ul> + <li>The native libraries created by the Android NDK can only be used on +devices running the Android 1.5 platform version or later. This is due to +toolchain and ABI related changes that make the native libraries incompatible +with 1.0 and 1.1 system images.</li> + <li>For this reason, you should use native libraries produced with the NDK in +applications that are deployable to devices running the Android 1.5 platform +version or later. To ensure compatibility, an application using a native library +produced with the NDK must declare a <code><uses-library></code> element +in its manifest file, with the attribute +<code>android:minSdkVersion="3"</code>.</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 and running a host-setup +script. </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 will not work with older versions of the +Android SDK. Also, take a moment to review the <a href="#requirements">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-<version></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><ndk></code>. </li> +<li>Open a terminal, change to the NDK directory, and run the host-setup script. +The script sets up your environment and generates a host configuration file used +later, when building your shared libraries. The path to the host-setup script +is: + +<p><code><ndk>/build/host-setup.sh</code></p> + +<p>If the script completes successfully, it prints a "Host setup complete." +message. If it fails, it prints instructions that you can follow to correct any +problems. </p> +</li> +</ol> + +<p>Once you have run the host-setup script, you are ready 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><ndk>/docs/</code> directory. In particular, please read the +OVERVIEW.TXT document completely, so that you understand the intent of the NDK +and how to use it.</p> + +<p>Here's the general outline of how you work with the NDK tools:</p> + +<ol> +<li>Place your native sources under +<code><ndk>/sources/<my_src>/...</code>. If you want, you can place +a symlink to your sources, rather than the sources themselves. The sources you +reference here are not strictly associated with a specific shared library or +Android application. Instead, they are accessible to any build configuration and +can be used to produce any number of shared libraries that can be used by any +Android application.</li> +<li>Create <code><ndk>/sources/<my_src>/Android.mk</code> to +describe your native sources to the NDK build system</li> +<li>Create <code><ndk>/apps/<my_app>/Application.mk</code> to +describe your Android application and native sources it needs to the NDK build +system. This file sets up the link between an Android SDK application project +and any number of shared libraries defined in the +<code><ndk>/sources/</code> folder and it specifies the path to the +application project that will receive the shared library built from the +sources.</li> +<li>Build your native code by running this make command from the top-level NDK +directory: + +<p><code>$ make APP=<my_app></code></p> + +<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 .apk file. </p></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">Using the Sample Applications</h2> + +<p>The NDK includes two sample applications that illustrate how to use native +code in your Android applications:</p> + +<ul> +<li><code>hello-jni</code> — 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> — 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> +</ul> + +<p>For each sample, the NDK includes an Android application project, as well as +the corresponding C source code and the necessary Android.mk and Application.mk +files. The application projects are provided in +<code><ndk>/apps/<app_name>/project/</code> and the C source for +each application is provided in +<code><ndk>/sources/samples/<library>/</code>.</p> + +<p>Once you have installed the NDK, you can build the shared libraries from the +NDK by using these commands from the root of the NDK directory:</p> +<ul> +<li><code>$ make APP=hello-jni</code> — compiles +<code><ndk>/sources/samples/hello-jni/hello-jni.c</code> and outputs a +shared library to +<code><ndk>/apps/hello-jni/project/libs/armeabi/libhello-jni.so</code>. +</li> +<li><code>$ make APP=two-libs</code> — compiles +<code><ndk>/sources/samples/two-libs/second.c</code> and +<code>first.c</code> and outputs a shared library to +<code><ndk>/apps/two-libs/project/libs/armeabi/libtwolib-second.so</code>. +</li> +</ul> + +<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><ndk>/apps/<app_name>/project/</code>. Then, set up an AVD, if +necessary, and build/run the application in the emulator. For more information +about creating a new Android project in Eclipse, see <a +href="{@docRoot}guide/developing/eclipse-adt.html">Developing in +Eclipse</a>.</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><ndk>/apps/<app_name>/project/</code>. Then set up an AVD, if +necessary, build your project in the usual way, and run it in the emulator. +For more information, see <a +href="{@docRoot}guide/developing/other-ide.html">Developing in Other +IDEs</a>.</li> +</ul> + +<h2>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> + + |