iconv动态库编译请参考：ubuntu-20.04.4环境下ndk-r21e 编译libiconv
libiconv-1.16动态库下载：Android libiconv.so动态库
一、创建android项目。
1、创建Native C++项目，点击下一步。
2、设置项目名称，点击下一步。
3、点击完成。
二、项目添加动态库。
1、将iconv动态库拷贝到项目中。
2、将iconv.h头文件拷贝到cpp文件夹。
三、配置cmake。
1、打开CMakeLists.txt文件，将libiconv.so动态库链接添加上。
CMakeLists.txt内容：
# For more information about using CMake with Android Studio, read the
# documentation: https://d.android.com/studio/projects/add-native-code.html
# Sets the minimum version of CMake required to build the native library.
cmake_minimum_required(VERSION 3.10.2)
# Declares and names the project.
project("iconv")
# Creates and names a library, sets it as either STATIC
# or SHARED, and provides the relative paths to its source code.
# You can define multiple libraries, and CMake builds them for you.
# Gradle automatically packages shared libraries with your APK.
add_library( # Sets the name of the library.
native-lib
# Sets the library as a shared library.
SHARED
# Provides a relative path to your source file(s).
native-lib.cpp )
# Searches for a specified prebuilt library and stores the path as a
# variable. Because CMake includes system libraries in the search path by
# default, you only need to specify the name of the public NDK library
# you want to add. CMake verifies that the library exists before
# completing its build.
find_library( # Sets the name of the path variable.
log-lib
# Specifies the name of the NDK library that
# you want CMake to locate.
log )
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fms-extensions")
#添加动态链接库
add_library( # Sets the name of the library.
iconv
# Sets the library as a shared library.
SHARED
# Provides a relative path to your source file(s).
IMPORTED )
set_target_properties(
iconv
PROPERTIES IMPORTED_LOCATION
${PROJECT_SOURCE_DIR}/libs/${ANDROID_ABI}/libiconv.so) #so文件位置
# Specifies libraries CMake should link to your target library. You
# can link multiple libraries, such as libraries you define in this
# build script, prebuilt third-party libraries, or system libraries.
target_link_libraries( # Specifies the target library.
native-lib
iconv
# Links the target library to the log library
# included in the NDK.
${log-lib})
2、MainActivity.java中加载libiconv.so库文件。
四、在native-lib.cpp中调用iconv函数。
native-lib.cpp内容：
#include#include #include "iconv.h" int GB2312ToUTF8(char* szSrc, size_t iSrcLen, char* szDst, size_t iDstLen) { iconv_t cd = iconv_open("utf-8", "gb2312"); if(0 == cd) return -2; memset(szDst, 0, iDstLen); char **src = &szSrc; char **dst = &szDst; if(-1 == (int)iconv(cd, src, &iSrcLen, dst, &iDstLen)) return -1; iconv_close(cd); return 0; } extern "C" JNIEXPORT jstring JNICALL Java_com_example_iconv_MainActivity_stringFromJNI( JNIEnv* env, jobject ) { unsigned char pIn[0x10] = {0xb1, 0xe0, 0xc2, 0xeb, 0xd7, 0xaa, 0xbb, 0xbb};//“编码转换”的GB2313格式 int len = sizeof(pIn); char ansUTF8[len]; GB2312ToUTF8((char*)pIn, len, ansUTF8, len); return env->NewStringUTF(ansUTF8); }
运行效果图：
五、编译过程中出现的错误
报错问题：
error: '__declspec' attributes are not enabled; use '-fdeclspec' or '-fms-extensions' to enable support for __declspec attributes extern LIBICONV_DLL_EXPORTED __declspec (dllimport) int _libiconv_version;
解决办法：在CMakeLists.txt文件中添加
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fms-extensions")
