Qt determines whether a file or folder exists and creates a folder

1. Determine if a folder exists
Parameter description:
QString fullpath;//folder full path
/* Method 1*/
BOOL Isdirexist (QString FullPath)
{
Qdir dir (FullPath);
if (Dir.exists ())
{
return true;
}
return false;
}
/* Method 2*/
BOOL Isdirexist (QString FullPath)
{
Qfileinfo FileInfo (FullPath);
if (Fileinfo.isdir ())
{
return true;
}
return false;
}

2. Determine if the file is not present
Parameter description:
QString fullfilename;//file full path (including file name)
/* Method 1*/
BOOL Isfileexist (QString fullfilename)
{
Qfileinfo FileInfo (filefullname);
if (Fileinfo.isfile ())
{
return true;
}
return false;
}

3. Determine if the file or folder is present (that is, you are not sure whether the string is a file or a folder path)
Parameter description:
QString fullfilepath;//path name
/* Method 1*/
BOOL Isfileexist (QString Fullfilepath)
{
Qfileinfo FileInfo (Fullfilepath);
if (Fileinfo.exists ())
{
return true;
}
return false;
}
/* Method 2*/
BOOL Isfileexist (QString Fullfilepath)
{
QFile file (Fullfilepath);
if (File.exists ())
{
return true;
}
return false;
}

4, determine whether the folder exists, does not exist to create
/* Method 1*/
BOOL Isdirexist (QString FullPath)
{
Qdir dir (FullPath);
if (Dir.exists ())
{
return true;
}
Else
{
bool OK = Dir.mkdir (fullPath);//create only one level subdirectory, that is, you must ensure that the parent directory exists
return OK;
}
}
/* Method 1*/
BOOL Isdirexist (QString FullPath)
{
Qdir dir (FullPath);
if (Dir.exists ())
{
return true;
}
Else
{
bool OK = Dir.mkpath (fullPath);//Create multilevel Directory
return OK;
}
}

5. The following is an excerpt of other network test code
{
Qfileinfo fi ("c:/123"); Directory exists
Qdebug () << fi.isfile (); False
Qdebug () << fi.isdir (); True
Qdebug () << fi.exists (); True
Qdebug () << fi.isroot (); False
Qdebug () << qfile::exists ("c:/123"); True
Qdebug () << qdir ("c:/123"). exists (); True

Fi.setfile ("C:/abc"); Directory does not exist
Qdebug () << fi.isfile (); False
Qdebug () << fi.isdir (); False
Qdebug () << fi.exists (); False
Qdebug () << fi.isroot (); False
Qdebug () << qfile::exists ("C:/abc"); False
Qdebug () << qdir ("C:/abc"). exists (); False

Fi.setfile ("c:/"); The drive that exists
Qdebug () << fi.isfile (); False
Qdebug () << fi.isdir (); True
Qdebug () << fi.exists (); True
Qdebug () << fi.isroot (); True
Qdebug () << qfile::exists ("c:/"); True
Qdebug () << qdir ("c:/"). exists (); True

Fi.setfile ("z:/"); Non-existent drive
Qdebug () << fi.isfile (); False
Qdebug () << fi.isdir (); False
Qdebug () << fi.exists (); False
Qdebug () << fi.isroot (); False
Qdebug () << qfile::exists ("z:/"); False
Qdebug () << qdir ("z:/"). exists (); False

Fi.setfile ("C:/123.lnk"); The shortcut exists and the file pointed to is present
Qdebug () << fi.isfile (); True
Qdebug () << fi.isdir (); False
Qdebug () << fi.exists (); True
Qdebug () << fi.isroot (); False
Qdebug () << qfile::exists ("C:/123.lnk"); True
Qdebug () << qdir ("C:/123.lnk"). exists (); False

Fi.setfile ("C:/456.lnk"); Shortcut exists but point to file does not exist
Qdebug () << fi.isfile (); False
Qdebug () << fi.isdir (); False
Qdebug () << fi.exists (); False
Qdebug () << fi.isroot (); False
Qdebug () << qfile::exists ("C:/456.lnk"); False
Qdebug () << qdir ("C:/456.lnk"). exists (); False
}
It can be seen that the Exists method, which is easy to confuse, is a common method of judging and can be seen as an expression
exists () = = (Isfile () | | isdir ())

In other words, it is not rigorous to judge whether a file or a folder exists simply by using the Exists method
For example, your intention is to determine whether the file exists, but the file does not exist, and happen to have a folder of the same name, then exists will also return true. The same is true for folders

A little summary based on the above code

Accurately determine if a file exists
1. Using the Qfileinfo::isfile () method

Accurately determine if a folder exists
1. Using the Qfileinfo::isdir () method
2. Using the Qdir::exists () method

Not sure if the string is a file or a folder path
1. Using the Qfileinfo::exists () method
2. Using the Qfile::exists () method