QT QString, wchar_t *, TCHAR, CString和其他字符或字符串类型的转化

//QString to wchar_t *:

const wchar_t * encodedName = reinterpret_cast<const wchar_t *>(fileName.utf16());



//QString to char * given a file name:

QByteArray fileName = QFile::encodeName(aFileName);

const char * encodedName = fileName.constData(); //Valid as long as fileName exists



//QString to char * (general case):

const char * tmp = str.toUtf8().constData();

[/code]

Windows 数据类型: http://msdn.microsoft.com/en-us/library/aa383751.aspx

[code lang="cpp"]

//TCHAR:

#ifdef UNICODE

typedef wchar_t TCHAR;

#else

typedef char TCHAR;

#endif



//LPCTSTR:

#ifdef UNICODE

typedef LPCWSTR LPCTSTR;

#else

typedef LPCSTR LPCTSTR;

#endif



//LPCSTR:

typedef const char * LPCSTR;



//LPCWSTR:

typedef const wchar_t * LPCWSTR;



//LPCWSTR to QString:

QString text(QString::fromUtf16(reinterpret_cast<const unsigned short *>(tmp)));

另一种解决办法是使用QString::fromWCharArray()，但这个函数可能导致一些尚未解决的wchar_t符号问题。



最佳的编程风格： 使用L来定义wchar_t宽字符串，比如 L"text" 字义了一个UNICODE字符串"text"。



今天又看到一个文章，关于字符串之间的转换，比较全面，在此将英文翻译并整理一下。

原文地址：http://hi.baidu.com/koko200147/blog/item/7e3cad828c9b9bb66d8119cb.html



QString与其他字符类型之间的转换，QString在Qt4中是UNICODE编码的，使用utf16规范。



QString::fromAscii ( const char * str, int size = -1 );

QString::fromLatin1 ( const char * str, int size = -1 );

QString::fromLocal8Bit ( const char * str, int size = -1 );

QString::fromRawData ( const QChar * unicode, int size );

QString::fromStdString ( const std::string & str );

QString::fromStdWString ( const std::wstring & str );

QString::fromUcs4 ( const uint * unicode, int size = -1 );

QString::fromUtf8 ( const char * str, int size = -1 );

QString::fromUtf16 ( const ushort * unicode, int size = -1 );

QString::fromWCharArray ( const wchar_t * string, int size = -1 );



//qstring ->std::string

QString::toStdString () ;

QString::toStdWString ();



//BSTR<->QString，不太了解BSTR是什么，还没用到过，所以不知道对不对

BSTR bstr_str;

QString q_str((QChar*)bstr_str, wcslen(bstr_str));

bstr_str = SysAllocString(q_str.utf16());//remember use SysFreeString on BSTR



//QString<->LPCSTR

QString::toLocal8Bit().constData();

QString::fromLocal8Bit ( const char * str, int size = -1 );



//QString<->LPCWSTR

QString::utf16();

QString::fromUtf16 ( const ushort * unicode, int size = -1 );



//QString<->CString

CString c_str(qstring::utf16());

QString fromUtf16 (LPCTSTR(c_str) );

CString转换为char*



//1.传给未分配内存的const char* （LPCTSTR）指针.

CString cstr(asdd);

const char* ch = (LPCTSTR)cstr;//ch指向的地址和cstr相同。但由于使用const保证ch不会修改，所以安全.



//2.传给未分配内存的指针.

CString cstr = "ASDDSD";

char *ch = cstr.GetBuffer(cstr1.GetLength() + 1);

cstr.ReleaseBuffer();

//修改ch指向的值等于修改cstr里面的值.

//PS:用完ch后,不用delete ch,因为这样会破坏cstr内部空间,容易造成程序崩溃.



//3.第二种用法。把CString 值赋给已分配内存的char *。

CString cstr1 = "ASDDSD";

int strLength = cstr1.GetLength() + 1;

char *pValue = new char[strLength];

strncpy(pValue, cstr1, strLength);



//4.第三种用法.把CString 值赋给已分配内存char[]数组.

CString cstr2 = "ASDDSD";

int strLength1 = cstr1.GetLength() + 1;

char chArray[100];

memset(chArray,0, sizeof(bool) * 100); //将数组的垃圾内容清空.

strncpy(chArray, cstr1, strLength1);



//5.如果上述都不行，使用以下方法

CString origCString("Hello, World!");

wchar_t* wCharString = origCString.GetBuffer(origCString.GetLength()+1);

size_t origsize = wcslen(wCharString) + 1;

size_t convertedChars = 0;

char *CharString;

CharString=new char(origsize);

wcstombs_s(&convertedChars, CharString, origsize, wCharString , _TRUNCATE);

cout << CharString << endl; //成功输出字符串"Hello,World"

从UTF8编码到GB编码的字符串转换方法：



QString Utf8_To_GB(QString strText)

{

    return QString::fromUtf8(strText.toLocal8Bit().data());

}

从GB编码到UTF8编码的字符串转换方法：



QString GB_To_Utf8(char *strText)

{

    return QString::fromLocal8Bit(strText);

}