由于项目需要在NDK中使用网络开发，对于c语言网络开发来说，libcurl库是个很不错的选择，但android系统中并没有自带该库，所以就得自己移植了。
下面是移植步骤：
1. 下载curl源码
我这里下载的是curl-7.22.0，源码下载地址为：http://curl.haxx.se/download.html
2. 准备android源码编译环境，
android源码应已全部编译过，具体细节这里不详述，我这里使用的是android2.2 froyo源码树。
3. 在android中编译curl
在最新的curl源码里其实已经带有Android.mk这个编译文件了，而且在这文件的开头注释部分比较详细地介绍编译方法。
1）拷贝curl源码至android源码树下的external/curl
2）cd 到 external/curl目录下，输入（红色字部分根据自己的环境做相应的更改）：
代码如下:
ANDROID_HOME=/home/braincol/workspace/android/froyo &&
NDK_HOME=/home/braincol/workspace/android/froyo/ndk &&
PATH="$ANDROID_HOME/prebuilt/linux-x86/toolchain/arm-eabi-4.4.0/bin:$PATH"
./configure --host=arm-linux CC=arm-eabi-gcc --with-random=/dev/urandom
CPPFLAGS="-I$NDK_HOME/platforms/android-8/arch-arm/usr/include
-I $ANDROID_HOME/external/curl/include/
-I $ANDROID_HOME/external/curl/3rd/include
-I $ANDROID_HOME/external/curl
-I $ANDROID_HOME/out/target/product/generic/obj/STATIC_LIBRARIES/libcurl_intermediates
-I $ANDROID_HOME/dalvik/libnativehelper/include/nativehelper
-I $ANDROID_HOME/system/core/include
-I $ANDROID_HOME/hardware/libhardware/include
-I $ANDROID_HOME/hardware/libhardware_legacy/include
-I $ANDROID_HOME/hardware/ril/include
-I $ANDROID_HOME/dalvik/libnativehelper/include
-I $ANDROID_HOME/frameworks/base/include
-I $ANDROID_HOME/frameworks/base/opengl/include
-I $ANDROID_HOME/frameworks/base/native/include
-I $ANDROID_HOME/external/skia/include
-I $ANDROID_HOME/out/target/product/generic/obj/include
-I $ANDROID_HOME/bionic/libc/arch-arm/include
-I $ANDROID_HOME/bionic/libc/include
-I $ANDROID_HOME/bionic/libstdc++/include
-I $ANDROID_HOME/bionic/libc/kernel/common
-I $ANDROID_HOME/bionic/libc/kernel/arch-arm
-I $ANDROID_HOME/bionic/libm/include
-I $ANDROID_HOME/bionic/libm/include/arch/arm
-I $ANDROID_HOME/bionic/libthread_db/include
-include $ANDROID_HOME/system/core/include/arch/linux-arm/AndroidConfig.h
-I $ANDROID_HOME/system/core/include/arch/linux-arm/
-D__ARM_ARCH_5__ -D__ARM_ARCH_5T__ -D__ARM_ARCH_5E__ -D__ARM_ARCH_5TE__ -DANDROID -DNDEBUG -DNDEBUG -DHAVE_CONFIG_H"
CFLAGS="-fno-exceptions -Wno-multichar -msoft-float -fpic -ffunction-sections
-funwind-tables -fstack-protector -Wa,--noexecstack -Werror=format-security
-fno-short-enums -march=armv5te -mtune=xscale -Wno-psabi -mthumb-interwork
-fmessage-length=0 -W -Wall -Wno-unused -Winit-self -Wpointer-arith
-Werror=return-type -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point
-g -Wstrict-aliasing=2 -finline-functions -fno-inline-functions-called-once
-fgcse-after-reload -frerun-cse-after-loop -frename-registers -UDEBUG
-mthumb -Os -fomit-frame-pointer -fno-strict-aliasing -finline-limit=64
-Wpointer-arith -Wwrite-strings -Wunused -Winline -Wnested-externs
-Wmissing-declarations -Wmissing-prototypes -Wno-long-long -Wfloat-equal
-Wno-multichar -Wsign-compare -Wno-format-nonliteral -Wendif-labels
-Wstrict-prototypes -Wdeclaration-after-statement -Wno-system-headers"
LIBS="-nostdlib -Bdynamic -Wl,-T,$ANDROID_HOME/build/core/armelf.x
-Wl,-dynamic-linker,/system/bin/linker -Wl,--gc-sections -Wl,-z,nocopyreloc
-L$ANDROID_HOME/out/target/product/generic/obj/lib -Wl,-z,noexecstack
-Wl,-rpath-link=$ANDROID_HOME/out/target/product/generic/obj/lib
-lc -llog -lcutils -lstdc++
-Wl,--no-undefined $ANDROID_HOME/prebuilt/linux-x86/toolchain/arm-eabi-4.4.0/lib/gcc/arm-eabi/4.4.0/libgcc.a
$ANDROID_HOME/out/target/product/generic/obj/lib/crtend_android.o
-lm $ANDROID_HOME/out/target/product/generic/obj/lib/crtbegin_dynamic.o
-L$ANDROID_HOME/external/curl/3rd/libs"
如果$ANDROID_HOME目录下没有ndk的开发包，那么到google的官网上下载一个放进去就行了。
3）cd 到源码根目录 mmm extern/libcurl：
编译完成之后，会生成静态库：out/target/product/generic/obj/STATIC_LIBRARIES/libcurl_intermediates/libcurl.a 。
4）如果要生成动态库需要修改curl下的Android.mk ：
代码如下:
LOCAL_PRELINK_MODULE := false
LOCAL_MODULE:= libcurl
LOCAL_MODULE_TAGS := optional
# Copy the licence to a place where Android will find it.
# Actually, this doesn't quite work because the build system searches
# for NOTICE files before it gets to this point, so it will only be seen
# on subsequent builds.
ALL_PREBUILT += $(LOCAL_PATH)/NOTICE
$(LOCAL_PATH)/NOTICE: $(LOCAL_PATH)/COPYING | $(ACP)
$(copy-file-to-target)
#include $(BUILD_STATIC_LIBRARY)
include $(BUILD_SHARED_LIBRARY)
4. 在android中测试curl
1）在android froyo源码树中下建立一个mytest目录，该目录下再建立一个curltest目录。
2）在目录curtest下创建curl-test.cpp：
代码如下:
#include
"curl/curl.h"#include
;int
main() { CURL
*curl; CURLcode
res; curl_global_init(CURL_GLOBAL_ALL); curl
= curl_easy_init(); if
(curl) { curl_easy_setopt(curl,
CURLOPT_URL, "http://www.cnblogs.com/hibraincol/");
res
= curl_easy_perform(curl); if
(0!=res) { printf("curl
error: %dn",
res); } curl_easy_cleanup(curl);
}
curl_global_cleanup(); return
0;}
3）在目录curtest下创建Android.mk：
代码如下:
#
curl test executable#LOCAL_PATH
:= $(call my-dir)include
$(CLEAR_VARS) LOCAL_C_INCLUDES
+= $(LOCAL_PATH)/3rd/include LOCAL_SRC_FILES:=
curl-test.cpp #
No shared libraries.LOCAL_SHARED_LIBRARIES
:= #
No static libraries.LOCAL_STATIC_LIBRARIES
:= libcurl LOCAL_MODULE
:= curl-testinclude
$(BUILD_EXECUTABLE)
4）把libcurl的头文件拷贝到curtest目录下的3rd/include目录下：
cp -rf out/target/product/generic/obj/include/libcurl/curl mytest/curltest/3rd/include
5）到android源码树的根目录下：mmm /mytest/curltest/
代码如下:
braincol@ubuntu:~/workspace/android/froyo$ mmm mytest/curltest/
============================================
PLATFORM_VERSION_CODENAME=REL
PLATFORM_VERSION=2.2
TARGET_PRODUCT=generic
TARGET_BUILD_VARIANT=eng
TARGET_SIMULATOR=
TARGET_BUILD_TYPE=release
TARGET_BUILD_APPS=
TARGET_ARCH=arm
HOST_ARCH=x86
HOST_OS=linux
HOST_BUILD_TYPE=release
BUILD_ID=MASTER
============================================
make: Entering directory `/home/braincol/workspace/android/froyo'
target thumb C++: curl-test