在使用ndk开发应用程序时，有时需要字符编码转换，这里使用开源库iconv进行字符编码转换，，代码如下
#include <jni.h>#include <string>#include <iconv.h>#include <iostream>class HStringConverter{char*_buf;size_t_bufSize;public:HStringConverter():_buf(nullptr), _bufSize(0){}~HStringConverter(){delete [] _buf;_buf = nullptr;_bufSize = 0;}char *convertString(const char * fromCode, const char * toCode, const char * source){size_t retlen = 0;size_t inbytesleft = strlen(source);if (!strncmp(fromCode, "UTF-16LE", 8)){inbytesleft = wcslen((wchar_t *)source) * 2;}size_t outbytesleft = inbytesleft * 4 + 2;retlen = outbytesleft;char *tmp = resize(outbytesleft);char * inbuf = (char *)source;char * outbuf = (char *)tmp;iconv_t cd = iconv_open(toCode, fromCode);size_t errorNo = iconv(cd, &inbuf, &inbytesleft, &outbuf, &outbytesleft);retlen -= outbytesleft;if (errorNo == -1){memcpy(tmp, source, inbytesleft);}else{memset(tmp + retlen, 0, outbytesleft);}iconv_close(cd);return tmp;}private:char *resize(int newSize) {if (_bufSize < newSize){delete [] _buf;_bufSize = newSize;_buf = new char[newSize];}memset(_buf, 0, newSize);return _buf;}};class GBK: public HStringConverter{const char *_gbk;public:GBK(const char *gbk):_gbk(gbk){ }char *toUtf8(){return convertString("GBK", "UTF-8", _gbk);}wchar_t *toUnicode(){return (wchar_t *)convertString("GBK", "UTF-16LE", _gbk);}};class Unicode: public HStringConverter{const wchar_t *_unicode;public:Unicode(const wchar_t *unicode):_unicode(unicode){}char *toGBK(){return convertString("UTF-16LE","GBK", (const char*)_unicode);}char *toUtf8(){return convertString("UTF-16LE","UTF-8", (const char*)_unicode);}};class Utf8: public HStringConverter{const char *_utf8;public:Utf8(const char *utf8):_utf8(utf8){}wchar_t *toUnicode(){return (wchar_t *)convertString("UTF-8", "UTF-16LE", _utf8);}char *toGBK(){return convertString("UTF-8", "GBK", _utf8);}};extern "C"jstring Java_com_irisking_attendserver_AttendServer_getName(JNIEnv *env, jobject thisz){const char *name = "韩呈杰";return env->NewStringUTF(GBK(name).toUtf8());}
这里支持UTF-16LE(Unicode)，UTF-8和GBK之间的编码相互转换。其中最后一个函数是使用示例。Android NDK r9c中，iconv.h有一处bug，需修改后才可编译，否则在编译时会报错，修改如下：
//#ifdef __cplus_plus//改为#ifdef __cplusplus} // extern "C"#endif完整的源代码，参见：Android NDK使用Iconv进行编码转换
而这些目标凝结成希望的萌芽，在汗水与泪水浇灌下，绽放成功之花。
