QByteArray类

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Qt GUI API中使用Unicode类型的字符串类QString。使用Unicode的好处是可以支持更多的地区语言，ASCII是Uncode的子集。

QByteArray和QString的方法和属性相似，可以参考QString。另外有一些与QByteArray相关的非成员函数：

//Related Non-Members//计算CRC16校验和quint16qChecksum ( const char * data, uint len )//压缩data，并返回新的值，参数compressionLevel的值是0~9QByteArrayqCompress ( const QByteArray & data, int compressionLevel = -1 )QByteArrayqCompress ( const uchar * data, int nbytes, int compressionLevel = -1 )//解压缩QByteArrayqUncompress ( const QByteArray & data )QByteArrayqUncompress ( const uchar * data, int nbytes )//格式化字符串intqsnprintf ( char * str, size_t n, const char * fmt, ... )intqvsnprintf ( char * str, size_t n, const char * fmt, va_list ap )//比较字符串intqstrcmp ( const char * str1, const char * str2 )//复制字符串char *qstrcpy ( char * dst, const char * src )char *qstrncpy ( char * dst, const char * src, uint len )//分配空间复制字符串返回char *qstrdup ( const char * src )//忽略大小写的字符串比较intqstricmp ( const char * str1, const char * str2 )intqstrnicmp ( const char * str1, const char * str2, uint len )//返回字符串的长度uintqstrlen ( const char * str )uintqstrnlen ( const char * str, uint maxlen )//固定长度内的字符串比较intqstrncmp ( const char * str1, const char * str2, uint len )//相关QByteArray和const char *的运算符booloperator!= ( const QByteArray & a1, const QByteArray & a2 )booloperator!= ( const QByteArray & a1, const char * a2 )booloperator!= ( const char * a1, const QByteArray & a2 )const QByteArrayoperator+ ( const QByteArray & a1, const QByteArray & a2 )const QByteArrayoperator+ ( const QByteArray & a1, const char * a2 )const QByteArrayoperator+ ( const QByteArray & a1, char a2 )const QByteArrayoperator+ ( const char * a1, const QByteArray & a2 )const QByteArrayoperator+ ( char a1, const QByteArray & a2 )booloperator< ( const QByteArray & a1, const QByteArray & a2 )booloperator< ( const QByteArray & a1, const char * a2 )booloperator< ( const char * a1, const QByteArray & a2 )QDataStream &operator<< ( QDataStream & out, const QByteArray & ba )booloperator<= ( const QByteArray & a1, const QByteArray & a2 )booloperator<= ( const QByteArray & a1, const char * a2 )booloperator<= ( const char * a1, const QByteArray & a2 )booloperator== ( const QByteArray & a1, const QByteArray & a2 )booloperator== ( const QByteArray & a1, const char * a2 )booloperator== ( const char * a1, const QByteArray & a2 )booloperator> ( const QByteArray & a1, const QByteArray & a2 )booloperator> ( const QByteArray & a1, const char * a2 )booloperator> ( const char * a1, const QByteArray & a2 )booloperator>= ( const QByteArray & a1, const QByteArray & a2 )booloperator>= ( const QByteArray & a1, const char * a2 )booloperator>= ( const char * a1, const QByteArray & a2 )QDataStream &operator>> ( QDataStream & in, QByteArray & ba )

QByteArray与QString之间的转换：

示例：

QByteArray cstr("abcd");
QString s = cstr;

QByteArray cstr("abcd");
QString s;
s.prepend(cstr);

QString s("hello");
QByteArray cstr = s.toAscii();

QString s("hello");
QByteArray cstr = s.toLatin1();

QByteArray类同样不以'\0'为结尾：如

QByteArray s;s.resize(5);s[0] = '1';s[1] = '2';s[2] = '3';s[3] = '\0';s[4] = 'a';cout << s << endl;

屏幕打印的是：“123 a”

转载自：http://blog.csdn.net/xgbing/article/details/7771898

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