Android NDK中提供了ndk-build脚本，以及若干mk文件，以简化ndk的开发，这对于开发一些小型应用来说足够了，但是对于一些大型项目，特别是涉及到很多第三方库时，管理起来就不是那么方便了（个人意见，Makefile写得好的人，可以无视）。在linux开源界，用得比较广泛的就是automake和cmake。本篇文章就是介绍如何使用cmake构建native程序的。

我之前写了一篇博客使用CMake构建android原生库，不过介绍的方法比较繁琐，最近在google code看到一个项目android-cmake，里面提供了脚本，这样使用起来就更方便了。下面就是介绍android-cmake的安装及使用方法。首先交代一下我的工作环境，ubuntu 10.10 32bit、Android NDK r6及Android SDK r12。接下来的步骤是：

1）下载android-cmake

    hg clone https://mogoweb.net/comment-page-1-2/ $HOME/android/android-cmake

2）使用NDK创建单独的工具链

    export NDK=~/android/android-ndk-r6

    $NDK/build/tools/make-standalone-toolchain.sh -platform=android-5 -install-dir=$HOME/android/android-toolchain

3）将如下代码加入$HOME/.profile

    export ANDROID_NDK_TOOLCHAIN_ROOT=$HOME/android/android-toolchain

    export ANDTOOLCHAIN=$HOME/android/android-cmake/toolchain/android.toolchain.cmake

    alias android-cmake=’cmake –DCMAKE_TOOLCHAIN_FILE=$ANDTOOLCHAIN ’

android-cmake包含了若干示例，从helloworld到复杂的boost库，先从一个简单的hello-cmake开始吧。

    cd samples/hello-cmake

    mkdir androidbuild

    cd androidbuild

    android-cmake ..

    make

即可编译出libhello-cmake.so，位于libs/armeabi-v7a。可以使用cmake GUI来修改某些设置:

    cmake-gui ..

注：这个例子只包含了java和jni的代码，并没有包括android工程，android工程在hello-android-cmake目录下。

在编译过程中，可能会出现如下错误：

- SWIG is not found
- The C compiler identification is GNU
- The CXX compiler identification is GNU
- Check for working C compiler: /home/alex/android/android-toolchain/bin/arm-linux-androideabi-gcc
- Check for working C compiler: /home/alex/android/android-toolchain/bin/arm-linux-androideabi-gcc — works
- Detecting C compiler ABI info
CMake Error: Could not COPY_FILE.
  OutputFile: ”
    copyFile: ‘/home/alex/android/android-cmake/samples/hello-cmake/androidbuild/CMakeFiles/CMakeDetermineCompilerABI_C.bin’
Unable to find executable for try_compile: tried "/home/alex/android/android-cmake/samples/hello-cmake/androidbuild/CMakeFiles/CMakeTmp/cmTryCompileExec" and "/home/alex/android/android-cmake/samples/hello-cmake/androidbuild/CMakeFiles/CMakeTmp/Debug/cmTryCompileExec" and "/home/alex/android/android-cmake/samples/hello-cmake/androidbuild/CMakeFiles/CMakeTmp/Development/cmTryCompileExec".
- Detecting C compiler ABI info - done
CMake Error at /usr/share/cmake-2.8/Modules/CMakeDetermineCompilerABI.cmake:40 (FILE):
  file STRINGS file
  "/home/alex/android/android-cmake/samples/hello-cmake/androidbuild/CMakeFiles/CMakeDetermineCompilerABI_C.bin"
  cannot be read.
Call Stack (most recent call first):
  /usr/share/cmake-2.8/Modules/CMakeTestCCompiler.cmake:71 (CMAKE_DETERMINE_COMPILER_ABI)
  CMakeLists.txt:3 (project)
- Check for working CXX compiler: /home/alex/android/android-toolchain/bin/arm-linux-androideabi-g++
- Check for working CXX compiler: /home/alex/android/android-toolchain/bin/arm-linux-androideabi-g++ — works
- Detecting CXX compiler ABI info
CMake Error: Could not COPY_FILE.
  OutputFile: ”
    copyFile: ‘/home/alex/android/android-cmake/samples/hello-cmake/androidbuild/CMakeFiles/CMakeDetermineCompilerABI_CXX.bin’
Unable to find executable for try_compile: tried "/home/alex/android/android-cmake/samples/hello-cmake/androidbuild/CMakeFiles/CMakeTmp/cmTryCompileExec" and "/home/alex/android/android-cmake/samples/hello-cmake/androidbuild/CMakeFiles/CMakeTmp/Debug/cmTryCompileExec" and "/home/alex/android/android-cmake/samples/hello-cmake/androidbuild/CMakeFiles/CMakeTmp/Development/cmTryCompileExec".
- Detecting CXX compiler ABI info - done
CMake Error at /usr/share/cmake-2.8/Modules/CMakeDetermineCompilerABI.cmake:40 (FILE):
  file STRINGS file
  "/home/alex/android/android-cmake/samples/hello-cmake/androidbuild/CMakeFiles/CMakeDetermineCompilerABI_CXX.bin"
  cannot be read.
Call Stack (most recent call first):
  /usr/share/cmake-2.8/Modules/CMakeTestCXXCompiler.cmake:64 (CMAKE_DETERMINE_COMPILER_ABI)
  CMakeLists.txt:3 (project)
- Configuring incomplete, errors occurred!

原因在于在测试编译器时，链接后的程序默认放在bin/armeabi-v7a目录下，而测试代码在另外的目录下去查找生成文件，解决的方法是修改$ANDTOOLCHAIN文件，将

set( EXECUTABLE_OUTPUT_PATH ${LIBRARY_OUTPUT_PATH_ROOT}/bin/${ARMEABI_NDK_NAME} CACHE PATH "Output directory for applications" FORCE)

改成
set( EXECUTABLE_OUTPUT_PATH ${LIBRARY_OUTPUT_PATH_ROOT} CACHE PATH "Output directory for applications" FORCE)

补充：

在使用cmake构建webkit android porting时，出现错误：

Could NOT find BISON (missing: BISON_EXECUTABLE)

原因在于$ANDTOOLCHAIN文件中修改了CMake系统变量：

set( CMAKE_FIND_ROOT_PATH_MODE_PROGRAM ONLY )

解决的方法是将代码中这样的语句注释掉。