The QFileInfo class provides an OS-independent API to retrieve information about file system entries. 更多...
| 頭： |
#include <QFileInfo>
|
| CMake: |
find_package(Qt6 REQUIRED COMPONENTS Core)
target_link_libraries(mytarget PRIVATE Qt6::Core)
|
| qmake: |
QT += core
|
此類 相等可比較 .
注意： 此類的所有函數 可重入 .
| QFileInfo () | |
| QFileInfo (const QFileDevice & file ) | |
| QFileInfo (const QString & path ) | |
(從 6.0 起)
|
QFileInfo (const std::filesystem::path & file ) |
| QFileInfo (const QDir & dir , const QString & path ) | |
(從 6.0 起)
|
QFileInfo (const QDir & dir , const std::filesystem::path & path ) |
| QFileInfo (const QFileInfo & fileinfo ) | |
| ~QFileInfo () | |
| QDir | absoluteDir () const |
| QString | absoluteFilePath () const |
| QString | absolutePath () const |
| QString | baseName () const |
| QDateTime | birthTime () const |
(從 6.6 起)
QDateTime
|
birthTime (const QTimeZone & tz ) const |
| QString | bundleName () const |
| bool | caching () const |
| QString | canonicalFilePath () const |
| QString | canonicalPath () const |
| QString | completeBaseName () const |
| QString | completeSuffix () const |
| QDir | dir () const |
| bool | exists () const |
| QString | fileName () const |
| QString | filePath () const |
| QDateTime | fileTime (QFileDevice::FileTime time ) const |
(從 6.6 起)
QDateTime
|
fileTime (QFileDevice::FileTime time , const QTimeZone & tz ) const |
(從 6.0 起)
std::filesystem::path
|
filesystemAbsoluteFilePath () const |
(從 6.0 起)
std::filesystem::path
|
filesystemAbsolutePath () const |
(從 6.0 起)
std::filesystem::path
|
filesystemCanonicalFilePath () const |
(從 6.0 起)
std::filesystem::path
|
filesystemCanonicalPath () const |
(從 6.0 起)
std::filesystem::path
|
filesystemFilePath () const |
(從 6.2 起)
std::filesystem::path
|
filesystemJunctionTarget () const |
(從 6.0 起)
std::filesystem::path
|
filesystemPath () const |
(從 6.6 起)
std::filesystem::path
|
filesystemReadSymLink () const |
(從 6.0 起)
std::filesystem::path
|
filesystemSymLinkTarget () const |
| QString | group () const |
| uint | groupId () const |
| bool | isAbsolute () const |
(從 6.4 起)
bool
|
isAlias () const |
| bool | isBundle () const |
| bool | isDir () const |
| bool | isExecutable () const |
| bool | isFile () const |
| bool | isHidden () const |
| bool | isJunction () const |
| bool | isNativePath () const |
| bool | isReadable () const |
| bool | isRelative () const |
| bool | isRoot () const |
| bool | isShortcut () const |
| bool | isSymLink () const |
| bool | isSymbolicLink () const |
| bool | isWritable () const |
(從 6.2 起)
QString
|
junctionTarget () const |
| QDateTime | lastModified () const |
(從 6.6 起)
QDateTime
|
lastModified (const QTimeZone & tz ) const |
| QDateTime | lastRead () const |
(從 6.6 起)
QDateTime
|
lastRead (const QTimeZone & tz ) const |
| bool | makeAbsolute () |
| QDateTime | metadataChangeTime () const |
(從 6.6 起)
QDateTime
|
metadataChangeTime (const QTimeZone & tz ) const |
| QString | owner () const |
| uint | ownerId () const |
| QString | path () const |
| bool | permission (QFileDevice::Permissions permissions ) const |
| QFileDevice::Permissions | permissions () const |
(從 6.6 起)
QString
|
readSymLink () const |
| void | refresh () |
| void | setCaching (bool enable ) |
| void | setFile (const QString & path ) |
(從 6.0 起)
void
|
setFile (const std::filesystem::path & path ) |
| void | setFile (const QFileDevice & file ) |
| void | setFile (const QDir & dir , const QString & path ) |
| qint64 | size () const |
(從 6.0 起)
void
|
stat () |
| QString | suffix () const |
| void | swap (QFileInfo & other ) |
| QString | symLinkTarget () const |
| QFileInfo & | operator= (QFileInfo && other ) |
| QFileInfo & | operator= (const QFileInfo & fileinfo ) |
| bool | exists (const QString & path ) |
| QFileInfoList | |
| bool | operator!= (const QFileInfo & lhs , const QFileInfo & rhs ) |
| bool | operator== (const QFileInfo & lhs , const QFileInfo & rhs ) |
(從 6.0 起)
|
QT_IMPLICIT_QFILEINFO_CONSTRUCTION |
QFileInfo provides information about a file system entry, such as its name, path, access rights and whether it is a regular file, directory or symbolic link. The entry's size and last modified/read times are also available. QFileInfo can also be used to obtain information about a Qt resource .
A QFileInfo can point to a file system entry with either an absolute or a relative path:
'/'
. On Windows, absolute paths begin with a drive specification (for example,
D:/
).
An example of an absolute path is the string
"/tmp/quartz"
. A relative path may look like
"src/fatlib"
. You can use the function
isRelative
() to check whether a QFileInfo is using a relative or an absolute path. You can call the function
makeAbsolute
() to convert a relative QFileInfo's path to an absolute path.
注意： Paths starting with a colon ( : ) are always considered absolute, as they denote a QResource .
The file system entry path that the QFileInfo works on is set in the constructor or later with setFile ()。使用 exists () to see if the entry actually exists and size () to get its size.
The file system entry's type is obtained with isFile (), isDir ()，和 isSymLink ()。 symLinkTarget () function provides the absolute path of the target the symlink points to.
The path elements of the file system entry can be extracted with
path
() 和
fileName
()。
fileName
()'s parts can be extracted with
baseName
(),
suffix
()，或
completeSuffix
(). QFileInfo objects referring to directories created by Qt classes will not have a trailing directory separator
'/'
. If you wish to use trailing separators in your own file info objects, just append one to the entry's path given to the constructors or
setFile
().
Date and time related information are returned by birthTime (), fileTime (), lastModified (), lastRead ()，和 metadataChangeTime (). Information about access permissions can be obtained with isReadable (), isWritable ()，和 isExecutable (). Ownership information can be obtained with owner (), ownerId (), group ()，和 groupId (). You can also examine permissions and ownership in a single statement using the permission () 函數。
On Unix (including macOS and iOS), the property getter functions in this class return the properties such as times and size of the target, not the symlink, because Unix handles symlinks transparently. Opening a symlink using QFile effectively opens the link's target. For example:
#ifdef Q_OS_UNIX QFileInfo info1("/home/bob/bin/untabify"); info1.isSymLink(); // returns true info1.absoluteFilePath(); // returns "/home/bob/bin/untabify" info1.size(); // returns 56201 info1.symLinkTarget(); // returns "/opt/pretty++/bin/untabify" QFileInfo info2(info1.symLinkTarget()); info2.isSymLink(); // returns false info2.absoluteFilePath(); // returns "/opt/pretty++/bin/untabify" info2.size(); // returns 56201 #endif
On Windows, shortcuts (
.lnk
files) are currently treated as symlinks. As on Unix systems, the property getters return the size of the target, not the
.lnk
file itself. This behavior is deprecated and will likely be removed in a future version of Qt, after which
.lnk
files will be treated as regular files.
#ifdef Q_OS_WIN QFileInfo info1("C:\\Users\\Bob\\untabify.lnk"); info1.isSymLink(); // returns true info1.absoluteFilePath(); // returns "C:/Users/Bob/untabify.lnk" info1.size(); // returns 63942 info1.symLinkTarget(); // returns "C:/Pretty++/untabify" QFileInfo info2(info1.symLinkTarget()); info2.isSymLink(); // returns false info2.absoluteFilePath(); // returns "C:/Pretty++/untabify" info2.size(); // returns 63942 #endif
在 NTFS 文件係統，默認情況下，齣於性能原因禁用所有權和權限校驗。要啓用它，包括以下行：
extern Q_CORE_EXPORT int qt_ntfs_permission_lookup;
然後打開和關閉權限校驗，通過遞增和遞減
qt_ntfs_permission_lookup
by 1.
qt_ntfs_permission_lookup++; // turn checking on qt_ntfs_permission_lookup--; // turn it off again
注意：
由於這是非原子全局變量，它纔安全遞增或遞減
qt_ntfs_permission_lookup
在除主綫程外的任何綫程已啓動前，或在除主綫程外的每個綫程已結束後。
注意：
從 Qt 6.6 起，變量
qt_ntfs_permission_lookup
被棄用。請使用下列替代。
管理權限校驗的安全且輕鬆方式是使用 RAII 類
QNtfsPermissionCheckGuard
.
void complexFunction() { QNtfsPermissionCheckGuard permissionGuard; // check is enabled // do complex things here that need permission check enabled } // as the guard goes out of scope the check is disabled
若需要更細粒度控製，取而代之，采用下列函數管理權限是可能的：
qAreNtfsPermissionChecksEnabled(); // check status qEnableNtfsPermissionChecks(); // turn checking on qDisableNtfsPermissionChecks(); // turn it off again
Some of QFileInfo's functions have to query the file system, but for performance reasons, some functions only operate on the path string. For example: To return the absolute path of a relative entry's path, absolutePath () 必須查詢文件係統。 path () 函數，不管怎樣，可以直接處理文件名，因此速度更快。
QFileInfo also caches information about the file system entry it refers to. Because the file system can be changed by other users or programs, or even by other parts of the same program, there is a function that refreshes the information stored in QFileInfo, namely refresh (). To switch off a QFileInfo's caching (that is, force it to query the underlying file system every time you request information from it), call setCaching (false).
Fetching information from the file system is typically done by calling (possibly) expensive system functions, so QFileInfo (depending on the implementation) might not fetch all the information from the file system at construction. To make sure that all information is read from the file system immediately, use the stat () member function.
birthTime (), fileTime (), lastModified (), lastRead ()，和 metadataChangeTime () return times in local time by default. Since native file system API typically uses UTC, this requires a conversion. If you don't actually need the local time, you can avoid this by requesting the time in QTimeZone::UTC 直接。
在 Android，會應用一些局限性當處理 內容 URI (統一資源標識符) :
Constructs an empty QFileInfo object that doesn't refer to any file system entry.
另請參閱 setFile ().
[explicit]
QFileInfo::
QFileInfo
(const
QFileDevice
&
file
)
Constructs a new QFileInfo that gives information about file file .
若 file has a relative path, the QFileInfo will also have a relative path.
另請參閱 isRelative ().
[explicit]
QFileInfo::
QFileInfo
(const
QString
&
path
)
Constructs a QFileInfo that gives information about a file system entry located at path that can be absolute or relative.
若 path is relative, the QFileInfo will also have a relative path.
另請參閱 setFile (), isRelative (), QDir::setCurrent ()，和 QDir::isRelativePath ().
[since 6.0]
QFileInfo::
QFileInfo
(const
std::filesystem::path
&
file
)
Constructs a new QFileInfo that gives information about the given file .
該函數在 Qt 6.0 引入。
另請參閱 setFile (), isRelative (), QDir::setCurrent ()，和 QDir::isRelativePath ().
[explicit]
QFileInfo::
QFileInfo
(const
QDir
&
dir
, const
QString
&
path
)
Constructs a new QFileInfo that gives information about the given file system entry path that is relative to the directory dir .
若 dir has a relative path, the QFileInfo will also have a relative path.
若 path is absolute, then the directory specified by dir will be disregarded.
另請參閱 isRelative ().
[since 6.0]
QFileInfo::
QFileInfo
(const
QDir
&
dir
, const
std::filesystem::path
&
path
)
Constructs a new QFileInfo that gives information about the file system entry at path that is relative to the directory dir .
若 dir has a relative path, the QFileInfo will also have a relative path.
若 path is absolute, then the directory specified by dir will be disregarded.
該函數在 Qt 6.0 引入。
Constructs a new QFileInfo that is a copy of the given fileinfo .
[noexcept]
QFileInfo::
~QFileInfo
()
銷毀 QFileInfo and frees its resources.
返迴 QDir object representing the absolute path of the parent directory of the file system entry that this QFileInfo refers to.
// Given a current working directory of "/home/user/Documents/memos/" QFileInfo info1(u"relativeFile"_s); qDebug() << info1.absolutePath(); // "/home/user/Documents/memos/" qDebug() << info1.baseName(); // "relativeFile" qDebug() << info1.absoluteDir(); // QDir(u"/home/user/Documents/memos"_s) qDebug() << info1.absoluteDir().path(); // "/home/user/Documents/memos" // A QFileInfo on a dir QFileInfo info2(u"/home/user/Documents/memos"_s); qDebug() << info2.absolutePath(); // "/home/user/Documents" qDebug() << info2.baseName(); // "memos" qDebug() << info2.absoluteDir(); // QDir(u"/home/user/Documents"_s) qDebug() << info2.absoluteDir().path(); // "/home/user/Documents"
另請參閱 dir (), filePath (), fileName ()，和 isRelative ().
Returns the absolute full path to the file system entry this QFileInfo refers to, including the entry's name.
On Unix, absolute paths begin with the directory separator
'/'
. On Windows, absolute paths begin with a drive specification (for example,
D:/
).
On Windows, the paths of network shares that are not mapped to a drive letter begin with
//sharename/
.
QFileInfo will uppercase drive letters. Note that QDir does not do this. The code snippet below shows this.
QFileInfo fi("c:/temp/foo");
qDebug() << fi.absoluteFilePath(); // "C:/temp/foo"
此函數返迴如同 filePath (), unless isRelative () is true. In contrast to canonicalFilePath (), symbolic links or redundant "." or ".." elements are not necessarily removed.
警告： 若 filePath () is empty the behavior of this function is undefined.
另請參閱 filePath (), canonicalFilePath ()，和 isRelative ().
Returns the absolute path of the file system entry this QFileInfo refers to, excluding the entry's name.
On Unix, absolute paths begin with the directory separator
'/'
. On Windows, absolute paths begin with a drive specification (for example,
D:/
).
On Windows, the paths of network shares that are not mapped to a drive letter begin with
//sharename/
.
In contrast to canonicalPath () symbolic links or redundant "." or ".." elements are not necessarily removed.
警告： 若 filePath () is empty the behavior of this function is undefined.
另請參閱 absoluteFilePath (), path (), canonicalPath (), fileName ()，和 isRelative ().
Returns the base name of the file without the path.
The base name consists of all characters in the file up to (but not including) the first '.' character.
範例：
QFileInfo fi("/tmp/archive.tar.gz"); QString base = fi.baseName(); // base = "archive"
The base name of a file is computed equally on all platforms, independent of file naming conventions (e.g., ".bashrc" on Unix has an empty base name, and the suffix is "bashrc").
另請參閱 fileName (), suffix (), completeSuffix ()，和 completeBaseName ().
Returns the date and time when the file was created (born), in local time.
If the file birth time is not available, this function returns an invalid QDateTime .
If the file is a symlink, this function returns information about the target, not the symlink.
This function overloads QFileInfo::birthTime(const
QTimeZone
&tz), and returns the same as
birthTime(QTimeZone::LocalTime)
.
另請參閱 lastModified (), lastRead (), metadataChangeTime ()，和 fileTime ().
[since 6.6]
QDateTime
QFileInfo::
birthTime
(const
QTimeZone
&
tz
) const
Returns the date and time when the file was created (born).
The returned time is in the time zone specified by tz . For example, you can use QTimeZone::LocalTime or QTimeZone::UTC to get the time in the Local time zone or UTC, respectively. Since native file system API typically uses UTC, using QTimeZone::UTC is often faster, as it does not require any conversions.
If the file birth time is not available, this function returns an invalid QDateTime .
If the file is a symlink, this function returns information about the target, not the symlink.
該函數在 Qt 6.6 引入。
另請參閱 lastModified (const QTimeZone &), lastRead (const QTimeZone &), metadataChangeTime (const QTimeZone &), and fileTime (QFileDevice::FileTime, const QTimeZone &).
Returns the name of the bundle.
On macOS and iOS this returns the proper localized name for a bundle if the path isBundle (). On all other platforms an empty QString 被返迴。
範例：
QFileInfo fi("/Applications/Safari.app"); QString bundle = fi.bundleName(); // name = "Safari"
另請參閱 isBundle (), filePath (), baseName ()，和 suffix ().
返迴
true
if caching is enabled; otherwise returns
false
.
另請參閱 setCaching () 和 refresh ().
Returns the file system entry's canonical path, including the entry's name, that is, an absolute path without symbolic links or redundant
'.'
or
'..'
元素。
If the entry does not exist, canonicalFilePath() returns an empty string.
另請參閱 filePath (), absoluteFilePath ()，和 dir ().
Returns the file system entry's canonical path (excluding the entry's name), i.e. an absolute path without symbolic links or redundant "." or ".." elements.
If the entry does not exist, this method returns an empty string.
另請參閱 path () 和 absolutePath ().
Returns the complete base name of the file without the path.
The complete base name consists of all characters in the file up to (but not including) the last '.' character.
範例：
QFileInfo fi("/tmp/archive.tar.gz"); QString base = fi.completeBaseName(); // base = "archive.tar"
另請參閱 fileName (), suffix (), completeSuffix ()，和 baseName ().
Returns the complete suffix (extension) of the file.
The complete suffix consists of all characters in the file after (but not including) the first '.'.
範例：
QFileInfo fi("/tmp/archive.tar.gz"); QString ext = fi.completeSuffix(); // ext = "tar.gz"
另請參閱 fileName (), suffix (), baseName ()，和 completeBaseName ().
返迴 QDir object representing the path of the parent directory of the file system entry that this QFileInfo refers to.
注意： The QDir returned always corresponds to the object's parent directory, even if the QFileInfo represents a directory.
For each of the following, dir() returns the
QDir
"~/examples/191697"
.
QFileInfo fileInfo1("~/examples/191697/.");
QFileInfo fileInfo2("~/examples/191697/..");
QFileInfo fileInfo3("~/examples/191697/main.cpp");
For each of the following, dir() returns the
QDir
"."
.
QFileInfo fileInfo4(".");
QFileInfo fileInfo5("..");
QFileInfo fileInfo6("main.cpp");
另請參閱 absolutePath (), filePath (), fileName (), isRelative ()，和 absoluteDir ().
返迴
true
if the file system entry this
QFileInfo
refers to exists; otherwise returns
false
.
注意：
If the entry is a symlink that points to a non-existing target, this method returns
false
.
[static]
bool
QFileInfo::
exists
(const
QString
&
path
)
返迴
true
if the file system entry
path
存在；否則返迴
false
.
注意：
若
path
is a symlink that points to a non-existing target, this method returns
false
.
注意：
使用此函數會更快相比使用
QFileInfo(path).exists()
對於文件係統訪問。
Returns the name of the file system entry this QFileInfo refers to, excluding the path.
範例：
QFileInfo fi("/tmp/archive.tar.gz"); QString name = fi.fileName(); // name = "archive.tar.gz"
注意：
若此
QFileInfo
is given a path ending with a directory separator
'/'
, the entry's name part is considered empty.
另請參閱 isRelative (), filePath (), baseName ()，和 suffix ().
Returns the path of the file system entry this QFileInfo refers to; the path may be absolute or relative.
另請參閱 absoluteFilePath (), canonicalFilePath ()，和 isRelative ().
返迴文件時間指定通過 time .
If the time cannot be determined, an invalid date time is returned.
If the file is a symlink, this function returns information about the target, not the symlink.
此函數重載
QFileInfo::fileTime
(QFileDevice::FileTime, const QTimeZone &), and returns the same as
fileTime(time, QTimeZone::LocalTime)
.
另請參閱 birthTime (), lastModified (), lastRead ()，和 metadataChangeTime ().
[since 6.6]
QDateTime
QFileInfo::
fileTime
(
QFileDevice::FileTime
time
, const
QTimeZone
&
tz
) const
返迴文件時間指定通過 time .
The returned time is in the time zone specified by tz . For example, you can use QTimeZone::LocalTime or QTimeZone::UTC to get the time in the Local time zone or UTC, respectively. Since native file system API typically uses UTC, using QTimeZone::UTC is often faster, as it does not require any conversions.
If the time cannot be determined, an invalid date time is returned.
If the file is a symlink, this function returns information about the target, not the symlink.
該函數在 Qt 6.6 引入。
另請參閱 birthTime (const QTimeZone &), lastModified (const QTimeZone &), lastRead (const QTimeZone &), metadataChangeTime (const QTimeZone &), and QDateTime::isValid ().
[since 6.0]
std::filesystem::path
QFileInfo::
filesystemAbsoluteFilePath
() const
返迴
absoluteFilePath
() as a
std::filesystem::path
.
該函數在 Qt 6.0 引入。
另請參閱 absoluteFilePath ().
[since 6.0]
std::filesystem::path
QFileInfo::
filesystemAbsolutePath
() const
返迴
absolutePath
() as a
std::filesystem::path
.
該函數在 Qt 6.0 引入。
另請參閱 absolutePath ().
[since 6.0]
std::filesystem::path
QFileInfo::
filesystemCanonicalFilePath
() const
返迴
canonicalFilePath
() as a
std::filesystem::path
.
該函數在 Qt 6.0 引入。
另請參閱 canonicalFilePath ().
[since 6.0]
std::filesystem::path
QFileInfo::
filesystemCanonicalPath
() const
返迴
canonicalPath
() as a
std::filesystem::path
.
該函數在 Qt 6.0 引入。
另請參閱 canonicalPath ().
[since 6.0]
std::filesystem::path
QFileInfo::
filesystemFilePath
() const
返迴
filePath
() as a
std::filesystem::path
.
該函數在 Qt 6.0 引入。
另請參閱 filePath ().
[since 6.2]
std::filesystem::path
QFileInfo::
filesystemJunctionTarget
() const
返迴
junctionTarget
() as a
std::filesystem::path
.
該函數在 Qt 6.2 引入。
另請參閱 junctionTarget ().
[since 6.0]
std::filesystem::path
QFileInfo::
filesystemPath
() const
返迴
path
() as a
std::filesystem::path
.
該函數在 Qt 6.0 引入。
另請參閱 path ().
[since 6.6]
std::filesystem::path
QFileInfo::
filesystemReadSymLink
() const
返迴
readSymLink
() as a
std::filesystem::path
.
該函數在 Qt 6.6 引入。
另請參閱 readSymLink ().
[since 6.0]
std::filesystem::path
QFileInfo::
filesystemSymLinkTarget
() const
返迴
symLinkTarget
() as a
std::filesystem::path
.
該函數在 Qt 6.0 引入。
另請參閱 symLinkTarget ().
Returns the group of the file. On Windows, on systems where files do not have groups, or if an error occurs, an empty string is returned.
This function can be time consuming under Unix (in the order of milliseconds).
If the file is a symlink, this function returns information about the target, not the symlink.
另請參閱 groupId (), owner ()，和 ownerId ().
Returns the id of the group the file belongs to.
On Windows and on systems where files do not have groups this function always returns (uint) -2.
If the file is a symlink, this function returns information about the target, not the symlink.
另請參閱 group (), owner ()，和 ownerId ().
返迴
true
if the file system entry's path is absolute, otherwise returns
false
(that is, the path is relative).
注意： Paths starting with a colon ( : ) are always considered absolute, as they denote a QResource .
另請參閱 isRelative ().
[since 6.4]
bool
QFileInfo::
isAlias
() const
返迴
true
if this object points to an alias; otherwise returns
false
.
Aliases only exist on macOS. They are treated as regular files, so opening an alias will open the file itself. In order to open the file or directory an alias references use symLinkTarget ().
注意： Even if an alias points to a non existing file, isAlias() returns true.
該函數在 Qt 6.4 引入。
另請參閱 isFile (), isDir (), isSymLink ()，和 symLinkTarget ().
返迴
true
if this object points to a bundle or to a symbolic link to a bundle on macOS and iOS; otherwise returns
false
.
If the file is a symlink, this function returns information about the target, not the symlink.
另請參閱 isDir (), isSymLink ()，和 isFile ().
返迴
true
if this object points to a directory or to a symbolic link to a directory. Returns
false
if the object points to something that is not a directory (such as a file) or that does not exist.
If the file is a symlink, this function returns information about the target, not the symlink.
另請參閱 isFile (), isSymLink ()，和 isBundle ().
返迴
true
if the file system entry this
QFileInfo
refers to is executable; otherwise returns
false
.
If the file is a symlink, this function returns information about the target, not the symlink.
另請參閱 isReadable (), isWritable ()，和 permission ().
返迴
true
if this object points to a file or to a symbolic link to a file. Returns
false
if the object points to something that is not a file (such as a directory) or that does not exist.
If the file is a symlink, this function returns information about the target, not the symlink.
另請參閱 isDir (), isSymLink ()，和 isBundle ().
返迴
true
if the file system entry this
QFileInfo
refers to is `hidden'; otherwise returns
false
.
注意：
此函數返迴
true
for the special entries "." and ".." on Unix, even though
QDir::entryList
treats them as shown. And note that, since this function inspects the file name, on Unix it will inspect the name of the symlink, if this file is a symlink, not the target's name.
On Windows, this function returns
true
if the target file is hidden (not the symlink).
返迴
true
if the object points to a junction; otherwise returns
false
.
Junctions only exist on Windows' NTFS file system, and are typically created by the
mklink
command. They can be thought of as symlinks for directories, and can only be created for absolute paths on the local volume.
返迴
true
if the file path can be used directly with native APIs. Returns
false
if the file is otherwise supported by a virtual file system inside Qt, such as
Qt 資源係統
.
注意： Native paths may still require conversion of path separators and character encoding, depending on platform and input requirements of the native API.
另請參閱 QDir::toNativeSeparators (), QFile::encodeName (), filePath (), absoluteFilePath ()，和 canonicalFilePath ().
返迴
true
if the user can read the file system entry this
QFileInfo
refers to; otherwise returns
false
.
If the file is a symlink, this function returns information about the target, not the symlink.
注意： 若 NTFS permissions check has not been enabled, the result on Windows will merely reflect whether the entry exists.
另請參閱 isWritable (), isExecutable ()，和 permission ().
返迴
true
if the file system entry's path is relative, otherwise returns
false
(that is, the path is absolute).
On Unix, absolute paths begin with the directory separator
'/'
. On Windows, absolute paths begin with a drive specification (for example,
D:/
).
注意： Paths starting with a colon ( : ) are always considered absolute, as they denote a QResource .
另請參閱 isAbsolute ().
返迴
true
if the object points to a directory or to a symbolic link to a directory, and that directory is the root directory; otherwise returns
false
.
返迴
true
if this object points to a shortcut; otherwise returns
false
.
Shortcuts only exist on Windows and are typically
.lnk
files. For instance, true will be returned for shortcuts (
*.lnk
files) on Windows, but false will be returned on Unix (including macOS and iOS).
The shortcut (.lnk) files are treated as regular files. Opening those will open the
.lnk
file itself. In order to open the file a shortcut references to, it must uses
symLinkTarget
() on a shortcut.
注意： Even if a shortcut (broken shortcut) points to a non existing file, isShortcut() returns true.
另請參閱 isFile (), isDir (), isSymbolicLink ()，和 symLinkTarget ().
返迴
true
if this object points to a symbolic link, shortcut, or alias; otherwise returns
false
.
Symbolic links exist on Unix (including macOS and iOS) and Windows and are typically created by the
ln -s
or
mklink
commands, respectively. Opening a symbolic link effectively opens the
link's target
.
In addition, true will be returned for shortcuts (
*.lnk
files) on Windows, and aliases on macOS. This behavior is deprecated and will likely change in a future version of Qt. Opening a shortcut or alias will open the
.lnk
or alias file itself.
範例：
QFileInfo info(fileName); if (info.isSymLink()) fileName = info.symLinkTarget();
注意：
exists
() 返迴
true
if the symlink points to an existing target, otherwise it returns
false
.
另請參閱 isFile (), isDir ()，和 symLinkTarget ().
返迴
true
if this object points to a symbolic link; otherwise returns
false
.
Symbolic links exist on Unix (including macOS and iOS) and Windows (NTFS-symlink) and are typically created by the
ln -s
or
mklink
commands, respectively.
Unix handles symlinks transparently. Opening a symbolic link effectively opens the link's target .
In contrast to
isSymLink
(), false will be returned for shortcuts (
*.lnk
files) on Windows and aliases on macOS. Use
QFileInfo::isShortcut
() 和
QFileInfo::isAlias
() 代替。
注意：
exists
() 返迴
true
if the symlink points to an existing target, otherwise it returns
false
.
另請參閱 isFile (), isDir (), isShortcut ()，和 symLinkTarget ().
返迴
true
if the user can write to the file system entry this
QFileInfo
refers to; otherwise returns
false
.
If the file is a symlink, this function returns information about the target, not the symlink.
注意： 若 NTFS permissions check has not been enabled, the result on Windows will merely reflect whether the entry is marked as Read Only.
另請參閱 isReadable (), isExecutable ()，和 permission ().
[since 6.2]
QString
QFileInfo::
junctionTarget
() const
Resolves an NTFS junction to the path it references.
Returns the absolute path to the directory an NTFS junction points to, or an empty string if the object is not an NTFS junction.
There is no guarantee that the directory named by the NTFS junction actually exists.
該函數在 Qt 6.2 引入。
另請參閱 isJunction (), isFile (), isDir (), isSymLink (), isSymbolicLink ()，和 isShortcut ().
Returns the date and time when the file was last modified.
If the file is a symlink, this function returns information about the target, not the symlink.
此函數重載
QFileInfo::lastModified
(const QTimeZone &), and returns the same as
lastModified(QTimeZone::LocalTime)
.
另請參閱 birthTime (), lastRead (), metadataChangeTime ()，和 fileTime ().
[since 6.6]
QDateTime
QFileInfo::
lastModified
(const
QTimeZone
&
tz
) const
Returns the date and time when the file was last modified.
The returned time is in the time zone specified by tz . For example, you can use QTimeZone::LocalTime or QTimeZone::UTC to get the time in the Local time zone or UTC, respectively. Since native file system API typically uses UTC, using QTimeZone::UTC is often faster, as it does not require any conversions.
If the file is a symlink, this function returns information about the target, not the symlink.
該函數在 Qt 6.6 引入。
另請參閱 birthTime (const QTimeZone &), lastRead (const QTimeZone &), metadataChangeTime (const QTimeZone &), and fileTime (QFileDevice::FileTime, const QTimeZone &).
Returns the date and time when the file was last read (accessed).
On platforms where this information is not available, returns the same time as lastModified ().
If the file is a symlink, this function returns information about the target, not the symlink.
此函數重載
QFileInfo::lastRead
(const QTimeZone &), and returns the same as
lastRead(QTimeZone::LocalTime)
.
另請參閱 birthTime (), lastModified (), metadataChangeTime ()，和 fileTime ().
[since 6.6]
QDateTime
QFileInfo::
lastRead
(const
QTimeZone
&
tz
) const
Returns the date and time when the file was last read (accessed).
The returned time is in the time zone specified by tz . For example, you can use QTimeZone::LocalTime or QTimeZone::UTC to get the time in the Local time zone or UTC, respectively. Since native file system API typically uses UTC, using QTimeZone::UTC is often faster, as it does not require any conversions.
On platforms where this information is not available, returns the same time as lastModified ().
If the file is a symlink, this function returns information about the target, not the symlink.
該函數在 Qt 6.6 引入。
另請參閱 birthTime (const QTimeZone &), lastModified (const QTimeZone &), metadataChangeTime (const QTimeZone &), and fileTime (QFileDevice::FileTime, const QTimeZone &).
If the file system entry's path is relative, this method converts it to an absolute path and returns
true
; if the path is already absolute, this method returns
false
.
另請參閱 filePath () 和 isRelative ().
Returns the date and time when the file's metadata was last changed, in local time.
A metadata change occurs when the file is first created, but it also occurs whenever the user writes or sets inode information (for example, changing the file permissions).
If the file is a symlink, this function returns information about the target, not the symlink.
This function overloads QFileInfo::metadataChangeTime(const
QTimeZone
&tz), and returns the same as
metadataChangeTime(QTimeZone::LocalTime)
.
另請參閱 birthTime (), lastModified (), lastRead ()，和 fileTime ().
[since 6.6]
QDateTime
QFileInfo::
metadataChangeTime
(const
QTimeZone
&
tz
) const
Returns the date and time when the file's metadata was last changed. A metadata change occurs when the file is first created, but it also occurs whenever the user writes or sets inode information (for example, changing the file permissions).
The returned time is in the time zone specified by tz . For example, you can use QTimeZone::LocalTime or QTimeZone::UTC to get the time in the Local time zone or UTC, respectively. Since native file system API typically uses UTC, using QTimeZone::UTC is often faster, as it does not require any conversions.
If the file is a symlink, this function returns information about the target, not the symlink.
該函數在 Qt 6.6 引入。
另請參閱 birthTime (const QTimeZone &), lastModified (const QTimeZone &), lastRead (const QTimeZone &), and fileTime (QFileDevice::FileTime time, const QTimeZone &).
Returns the owner of the file. On systems where files do not have owners, or if an error occurs, an empty string is returned.
This function can be time consuming under Unix (in the order of milliseconds). On Windows, it will return an empty string unless the NTFS permissions check has been enabled.
If the file is a symlink, this function returns information about the target, not the symlink.
另請參閱 ownerId (), group ()，和 groupId ().
Returns the id of the owner of the file.
On Windows and on systems where files do not have owners this function returns ((uint) -2).
If the file is a symlink, this function returns information about the target, not the symlink.
另請參閱 owner (), group ()，和 groupId ().
Returns the path of the file system entry this QFileInfo refers to, excluding the entry's name.
注意：
若此
QFileInfo
is given a path ending with a directory separator
'/'
, the entry's name part is considered empty. In this case, this function will return the entire path.
另請參閱 filePath (), absolutePath (), canonicalPath (), dir (), fileName ()，和 isRelative ().
Tests for file permissions. The permissions argument can be several flags of type QFile::Permissions OR-ed together to check for permission combinations.
On systems where files do not have permissions this function always returns
true
.
注意： The result might be inaccurate on Windows if the NTFS permissions check has not been enabled.
範例：
QFileInfo fi("/tmp/archive.tar.gz"); if (fi.permission(QFile::WriteUser | QFile::ReadGroup)) qWarning("I can change the file; my group can read the file"); if (fi.permission(QFile::WriteGroup | QFile::WriteOther)) qWarning("The group or others can change the file");
If the file is a symlink, this function returns information about the target, not the symlink.
另請參閱 isReadable (), isWritable ()，和 isExecutable ().
Returns the complete OR-ed together combination of QFile::Permissions for the file.
注意： The result might be inaccurate on Windows if the NTFS permissions check has not been enabled.
If the file is a symlink, this function returns information about the target, not the symlink.
[since 6.6]
QString
QFileInfo::
readSymLink
() const
Read the path the symlink references.
Returns the raw path referenced by the symbolic link, without resolving a relative path relative to the directory containing the symbolic link. The returned string will only be an absolute path if the symbolic link actually references it as such. Returns an empty string if the object is not a symbolic link.
該函數在 Qt 6.6 引入。
另請參閱 symLinkTarget (), exists (), isSymLink (), isDir ()，和 isFile ().
Refreshes the information about the file system entry this QFileInfo refers to, that is, reads in information from the file system the next time a cached property is fetched.
若 enable is true, enables caching of file information. If enable is false caching is disabled.
When caching is enabled, QFileInfo reads the file information from the file system the first time it's needed, but generally not later.
Caching is enabled by default.
Sets the path of the file system entry that this QFileInfo provides information about to path that can be absolute or relative.
On Unix, absolute paths begin with the directory separator
'/'
. On Windows, absolute paths begin with a drive specification (for example,
D:/
).
Relative paths begin with a directory name or a regular file name and specify a file system entry's path relative to the current working directory.
範例：
QFileInfo info("/usr/bin/env"); QString path = info.absolutePath(); // path = /usr/bin QString base = info.baseName(); // base = env info.setFile("/etc/hosts"); path = info.absolutePath(); // path = /etc base = info.baseName(); // base = hosts
另請參閱 isFile (), isRelative (), QDir::setCurrent ()，和 QDir::isRelativePath ().
[since 6.0]
void
QFileInfo::
setFile
(const
std::filesystem::path
&
path
)
Sets the path of file system entry that this QFileInfo provides information about to path .
若 path is relative, the QFileInfo will also have a relative path.
該函數在 Qt 6.0 引入。
這是重載函數。
Sets the file that the QFileInfo provides information about to file .
若 file includes a relative path, the QFileInfo will also have a relative path.
另請參閱 isRelative ().
這是重載函數。
Sets the path of the file system entry that this QFileInfo provides information about to path in directory dir .
若 dir has a relative path, the QFileInfo will also have a relative path.
若 path is absolute, then the directory specified by dir will be disregarded.
另請參閱 isRelative ().
Returns the file size in bytes. If the file does not exist or cannot be fetched, 0 is returned.
If the file is a symlink, this function returns information about the target, not the symlink.
另請參閱 exists ().
[since 6.0]
void
QFileInfo::
stat
()
Reads all attributes from the file system.
This is useful when information about the file system is collected in a worker thread, and then passed to the UI in the form of caching QFileInfo 實例。
該函數在 Qt 6.0 引入。
另請參閱 setCaching () 和 refresh ().
Returns the suffix (extension) of the file.
The suffix consists of all characters in the file after (but not including) the last '.'.
範例：
QFileInfo fi("/tmp/archive.tar.gz"); QString ext = fi.suffix(); // ext = "gz"
The suffix of a file is computed equally on all platforms, independent of file naming conventions (e.g., ".bashrc" on Unix has an empty base name, and the suffix is "bashrc").
另請參閱 fileName (), completeSuffix (), baseName ()，和 completeBaseName ().
[noexcept]
void
QFileInfo::
swap
(
QFileInfo
&
other
)
Swaps this file info with other 。此操作很快且從不失敗。
Returns the absolute path to the file or directory a symbolic link points to, or an empty string if the object isn't a symbolic link.
此名稱可能不錶示現有文件；它隻是字符串。
注意：
exists
() 返迴
true
if the symlink points to an existing target, otherwise it returns
false
.
另請參閱 exists (), isSymLink (), isDir ()，和 isFile ().
[noexcept]
QFileInfo
&QFileInfo::
operator=
(
QFileInfo
&&
other
)
移動賦值 other 到此 QFileInfo 實例。
Makes a copy of the given fileinfo 並將其賦值給此 QFileInfo .
[noexcept]
bool
operator!=
(const
QFileInfo
&
lhs
, const
QFileInfo
&
rhs
)
返迴
true
if
QFileInfo
lhs
refers to a different file system entry than the one referred to by
rhs
；否則返迴
false
.
另請參閱 operator== ().
[noexcept]
bool
operator==
(const
QFileInfo
&
lhs
, const
QFileInfo
&
rhs
)
返迴
true
if
QFileInfo
lhs
and
QFileInfo
rhs
refer to the same entry on the file system; otherwise returns
false
.
Note that the result of comparing two empty QFileInfo objects, containing no file system entry references (paths that do not exist or are empty), is undefined.
警告： This will not compare two different symbolic links pointing to the same target.
警告： On Windows, long and short paths that refer to the same file system entry are treated as if they referred to different entries.
另請參閱 operator!= ().
[since 6.0]
QT_IMPLICIT_QFILEINFO_CONSTRUCTION
Defining this macro makes most QFileInfo constructors implicit instead of explicit. Since construction of QFileInfo objects is expensive, one should avoid accidentally creating them, especially if cheaper alternatives exist. For instance:
QDirIterator it(dir);
while (it.hasNext()) {
// Implicit conversion from QString (returned by it.next()):
// may create unnecessary data structures and cause additional
// accesses to the file system. Unless this macro is defined,
// this line does not compile.
QFileInfo fi = it.next();
~~~
}
Instead, use the right API:
QDirIterator it(dir); while (it.hasNext()) { // Extract the QFileInfo from the iterator directly: QFileInfo fi = it.nextFileInfo(); ~~~ }
Construction from QString , QFile , and so on is always possible by using direct initialization instead of copy initialization:
QFileInfo fi1 = some_string; // Does not compile unless this macro is defined QFileInfo fi2(some_string); // OK QFileInfo fi3{some_string}; // Possibly better, avoids the risk of the Most Vexing Parse auto fi4 = QFileInfo(some_string); // OK
This macro is provided for compatibility reason. Its usage is not recommended in new code.
該宏在 Qt 6.0 引入。