#include <QTextCodec>
qmake: QT += core 【自动加】
QTextCodec *codec = QTextCodec::codecForName("GBK"); //创建GBK编码转换对象
QString string = codec->toUnicode("GBK编码中文字符串"); //转换成qt支持的Unicode编码字符串
支持转换的编码有：
Big5
Big5-HKSCS
CP949--GBK
EUC-JP
EUC-KR
GB18030
HP-ROMAN8
IBM 850
IBM 866
IBM 874
ISO 2022-JP
ISO 8859-1 to 10
ISO 8859-13 to 16
Iscii-Bng, Dev, Gjr, Knd, Mlm, Ori, Pnj, Tlg, and Tml
KOI8-R
KOI8-U
Macintosh
Shift-JIS
TIS-620
TSCII
UTF-8
UTF-16
UTF-16BE
UTF-16LE
UTF-32
UTF-32BE
UTF-32LE
Windows-1250 to 1258
img_name.toUtf8() //把字符串转换成utf8编码
