Qt中对于SHGetSpecialFolderPath函数的调用

首先介绍一下SHGetSpecialFolderPath函数：

该函数用于获取指定的系统路径。需要包含#include   <shlobj.h> 

BOOL SHGetSpecialFolderPath(

  HWND hwndOwner,
  _Out_  LPTSTR lpszPath,
  _In_   int csidl,
  _In_   BOOL fCreate
);

通过分析Qt代码中对于SHGetSpecialFolderPath函数的调用主要在2个类里面。一个为QDesktopServices类，另外一个为QSettings类。

 QString QDesktopServices::storageLocation(StandardLocation type)

{
    QString result;

#ifndef Q_OS_WINCE
        QSystemLibrary library(QLatin1String("shell32"));
#else
        QSystemLibrary library(QLatin1String("coredll"));
#endif // Q_OS_WINCE
    typedef BOOL (WINAPI*GetSpecialFolderPath)(HWND, LPWSTR, int, BOOL);
    static GetSpecialFolderPath SHGetSpecialFolderPath =
            (GetSpecialFolderPath)library.resolve("SHGetSpecialFolderPathW");
    if (!SHGetSpecialFolderPath)
        return QString();

    wchar_t path[MAX_PATH];

    switch (type) {
    case DataLocation:
#if defined Q_WS_WINCE
        if (SHGetSpecialFolderPath(0, path, CSIDL_APPDATA, FALSE))
#else
        if (SHGetSpecialFolderPath(0, path, CSIDL_LOCAL_APPDATA, FALSE))
#endif
            result = QString::fromWCharArray(path);
        if (!QCoreApplication::organizationName().isEmpty())
            result = result + QLatin1String("\\") + QCoreApplication::organizationName();
        if (!QCoreApplication::applicationName().isEmpty())
            result = result + QLatin1String("\\") + QCoreApplication::applicationName();
        break;

    case DesktopLocation:
        if (SHGetSpecialFolderPath(0, path, CSIDL_DESKTOPDIRECTORY, FALSE))
            result = QString::fromWCharArray(path);
        break;

    case DocumentsLocation:
        if (SHGetSpecialFolderPath(0, path, CSIDL_PERSONAL, FALSE))
            result = QString::fromWCharArray(path);
        break;

    case FontsLocation:
        if (SHGetSpecialFolderPath(0, path, CSIDL_FONTS, FALSE))
            result = QString::fromWCharArray(path);
        break;

    case ApplicationsLocation:
        if (SHGetSpecialFolderPath(0, path, CSIDL_PROGRAMS, FALSE))
            result = QString::fromWCharArray(path);
        break;

    case MusicLocation:
        if (SHGetSpecialFolderPath(0, path, CSIDL_MYMUSIC, FALSE))
            result = QString::fromWCharArray(path);
        break;

    case MoviesLocation:
        if (SHGetSpecialFolderPath(0, path, CSIDL_MYVIDEO, FALSE))
            result = QString::fromWCharArray(path);
        break;

    case PicturesLocation:
        if (SHGetSpecialFolderPath(0, path, CSIDL_MYPICTURES, FALSE))
            result = QString::fromWCharArray(path);
        break;

    case CacheLocation:
        // Although Microsoft has a Cache key it is a pointer to IE's cache, not a cache
        // location for everyone.  Most applications seem to be using a
        // cache directory located in their AppData directory
        return storageLocation(DataLocation) + QLatin1String("\\cache");

    case QDesktopServices::HomeLocation:
        return QDir::homePath(); break;

    case QDesktopServices::TempLocation:
        return QDir::tempPath(); break;

    default:
        break;
    }
    return result;
}

其实该函数提供的地址远远不止这些东西，只是Qt选择部分系统路径。

 如果需要扩充该类的功能的话，可以手工添加进去。