The Android NDK provides tools that allow Android application developers +to embed components that make use of native code in their Android applications. +
+ +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.
+ +The NDK provides:
+ +This release of the NDK supports two ARM instruction sets:
+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 and Thumb-2 instructions. You can target either or +both of the instruction sets — ARMv5TE is the default, but switching to +ARMv7-A is as easy as adding a single line to the application's Application.mk +file, without needing to change anything else in the file. You can also build +for both architectures at the same time and have everything stored in the final +.apk. Complete information is provided in the CPU-ARCH-ABIS.TXT in the NDK +package.
+ +The NDK provides stable headers for libc (the C library), libm (the Math +library), OpenGL ES (3D graphics library), the JNI interface, and other +libraries, as listed in the section below.
+ +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.
+ +Please note that the NDK does not enable you to develop native-only +applications. Android's primary runtime remains the Dalvik virtual machine.
+ +The NDK includes a set of cross-toolchains (compilers, linkers, etc..) that +can generate native ARM binaries on Linux, OS X, and Windows (with Cygwin) +platforms.
+ +It provides a set of system headers for stable native APIs that are +guaranteed to be supported in all later releases of the platform:
+ +The NDK also provides a build system that lets you work efficiently with your +sources, without having to handle the toolchain/platform/CPU/ABI details. You +create very short build files to describe which sources to compile and which +Android application will use them — the build system compiles the sources +and places the shared libraries directly in your application project.
+ +Important: With the exception of the +libraries listed above, native system libraries in the Android platform are +not stable and may change in future platform versions. +Your applications should only make use of the stable native system +libraries provided in this NDK.
+ +The NDK package includes a set of documentation that describes the
+capabilities of the NDK and how to use it to create shared libraries for your
+Android applications. In this release, the documentation is provided only in the
+downloadable NDK package. You can find the documentation in the
+<ndk>/docs/ directory. Included are these files:
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
+<ndk>/docs/system/libc/ directory:
The NDK includes four sample Android applications that illustrate how to use +native code in your Android applications:
+ +hello-jni — a simple application that loads a string from
+a native method implemented in a shared library and then displays it in the
+application UI. two-libs — a simple application that loads a shared
+library dynamically and calls a native method provided by the library. In this
+case, the method is implemented in a static library that is imported by the
+shared library. san-angeles — a simple application that renders 3D
+graphics through the native OpenGL ES APIs, while managing activity lifecycle
+with a {@link android.opengl.GLSurfaceView GLSurfaceView} object. hello-gl2 — a simple application that renders a triangle
+using OpenGL ES 2.0 vertex and fragment shaders.For more information, see Using the Sample +Applications.
+ +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.
+ +<uses-sdk>
+element in its manifest file, with an android:minSdkVersion attribute
+value of "3" or higher. For example:
+
+<manifest> + ... + <uses-sdk android:minSdkVersion="3" /> + ... +</manifest>+ +
Additionally, 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.
+ +| Version | +Platform Compatibility | +
|---|---|
| OpenGL ES 1.1 | Android 1.6 (API Level 4) or higher |
| OpenGL ES 2.0 | Android 2.0 (API Level 5) or higher |
To ensure compatibility, the application must declare the proper
+android:minSdkVersion attribute value, as given in the table
+above.
For more information about API Level and its relationship to Android +platform versions, see +Android API Levels.
Installing the NDK on your development computer is straightforward and +involves extracting the NDK from its download package and running a host-setup +script.
+ +Before you get started make sure that you have downloaded the latest Android SDK 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 System +and Software Requirements for the NDK, if you haven't already.
+ +To install the NDK, follow these steps:
+ +android-ndk-<version>. You can rename the NDK directory if
+necessary and you can move it to any location on your computer. This
+documentation refers to the NDK directory as <ndk>. <ndk>/build/host-setup.sh
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.
+Once you have run the host-setup script, you are ready start working with the +NDK.
+ +Once you've installed the NDK successfully, take a few minutes to read the
+documentation included in the NDK. You can find the documentation in the
+<ndk>/docs/ directory. In particular, please read the
+OVERVIEW.TXT document completely, so that you understand the intent of the NDK
+and how to use it.
If you used a previous version of the NDK, take a moment to review the +list of NDK changes in the CHANGES.TXT document.
+ +Here's the general outline of how you work with the NDK tools:
+ +<project>/jni/...<project>/jni/Android.mk to
+describe your native sources to the NDK build system<ndk>/apps/<my_app>/Application.mk 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
+<project>/jni/ folder and it specifies the path to the
+application project that will receive the shared library built from the
+sources.$ make APP=<my_app>
The build tools copy the stripped, shared libraries needed by your +application to the proper location in the application's project directory.
+For complete information on all of the steps listed above, please see the +documentation included with the NDK package.
+ + +The NDK includes four sample applications that illustrate how to use native +code in your Android applications:
+ +hello-jni — a simple application that loads a string from
+a native method implemented in a shared library and then displays it in the
+application UI. two-libs — a simple application that loads a shared
+library dynamically and calls a native method provided by the library. In this
+case, the method is implemented in a static library imported by the shared
+library. san-angeles — a simple application that renders 3D
+graphics through the native OpenGL ES APIs, while managing activity lifecycle
+with a {@link android.opengl.GLSurfaceView GLSurfaceView} object. hello-gl2 — a simple application that renders a triangle
+using OpenGL ES 2.0 vertex and fragment shaders.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
+<ndk>/apps/<app_name>/project/ and the C source for
+each application is provided in
+<ndk>/apps/<app_name>/project/jni/.
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:
+$ make APP=hello-jni — compiles
+<ndk>/apps/hello-jni/project/jni/hello-jni.c and outputs a
+shared library to
+<ndk>/apps/hello-jni/project/libs/armeabi/libhello-jni.so.
+$ make APP=two-libs — compiles
+<ndk>/apps/two-libs/project/jni/second.c and
+first.c and outputs a shared library to
+<ndk>/apps/two-libs/project/libs/armeabi/libtwolib-second.so.
+Next, build the sample Android applications that use the shared +libraries:
+ +<ndk>/apps/<app_name>/project/. 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 Developing in
+Eclipse.android tool to create
+the build file for each of the sample projects at
+<ndk>/apps/<app_name>/project/. Then set up an AVD, if
+necessary, build your project in the usual way, and run it in the emulator.
+For more information, see Developing in Other
+IDEs.If you have questions about the NDK or would like to read or contribute to +discussions about it, please visit the android-ndk group and +mailing list.
+ + diff --git a/docs/html/sdk/sdk_toc.cs b/docs/html/sdk/sdk_toc.cs index 556f78164241b..8ef1176ac2475 100644 --- a/docs/html/sdk/sdk_toc.cs +++ b/docs/html/sdk/sdk_toc.cs @@ -126,7 +126,8 @@ Windows, r3 new!