QFileSystemModel Class | Qt Widgets 5.14.1

Qt 5.14 | Qt Widgets | C++ Classes | QFileSystemModel

Qt 5.14.1 Reference Documentation

# QFileSystemModel Class

The QFileSystemModel class provides a data model for the local filesystem. More...

Header: | #include <QFileSystemModel>
qmake: | QT += widgets
Since: | Qt 4.4
Inherits: | QAbstractItemModel

This class was introduced in Qt 4.4.

- List of all members, including inherited members

## Public Types

enum | Option { DontWatchForChanges, DontResolveSymlinks, DontUseCustomDirectoryIcons }
flags | Options
enum | Roles { FileIconRole, FilePathRole, FileNameRole, FilePermissions }

## Properties

- nameFilterDisables : bool
- options : Options
- readOnly : bool
- resolveSymlinks : bool

## Public Functions

| QFileSystemModel(QObject *parent = nullptr)
virtual | ~QFileSystemModel()
QIcon | fileIcon(const QModelIndex &index) const
QFileInfo | fileInfo(const QModelIndex &index) const
QString | fileName(const QModelIndex &index) const
QString | filePath(const QModelIndex &index) const
QDir::Filters | filter() const
QFileIconProvider * | iconProvider() const
QModelIndex | index(const QString &path, int column = 0) const
bool | isDir(const QModelIndex &index) const
bool | isReadOnly() const
QDateTime | lastModified(const QModelIndex &index) const
QModelIndex | mkdir(const QModelIndex &parent, const QString &name)
QVariant | myComputer(int role = Qt::DisplayRole) const
bool | nameFilterDisables() const
QStringList | nameFilters() const
QFileSystemModel::Options | options() const
QFile::Permissions | permissions(const QModelIndex &index) const
bool | remove(const QModelIndex &index)
bool | resolveSymlinks() const
bool | rmdir(const QModelIndex &index)
QDir | rootDirectory() const
QString | rootPath() const
void | setFilter(QDir::Filters filters)
void | setIconProvider(QFileIconProvider *provider)
void | setNameFilterDisables(bool enable)
void | setNameFilters(const QStringList &filters)
void | setOption(QFileSystemModel::Option option, bool on = true)
void | setOptions(QFileSystemModel::Options options)
void | setReadOnly(bool enable)
void | setResolveSymlinks(bool enable)
QModelIndex | setRootPath(const QString &newPath)
qint64 | size(const QModelIndex &index) const
bool | testOption(QFileSystemModel::Option option) const
QString | type(const QModelIndex &index) const

## Reimplemented Public Functions

virtual bool | canFetchMore(const QModelIndex &parent) const override
virtual int | columnCount(const QModelIndex &parent = QModelIndex()) const override
virtual QVariant | data(const QModelIndex &index, int role = Qt::DisplayRole) const override
virtual bool | dropMimeData(const QMimeData *data, Qt::DropAction action, int row, int column, const QModelIndex &parent) override
virtual void | fetchMore(const QModelIndex &parent) override
virtual Qt::ItemFlags | flags(const QModelIndex &index) const override
virtual bool | hasChildren(const QModelIndex &parent = QModelIndex()) const override
virtual QVariant | headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const override
virtual QModelIndex | index(int row, int column, const QModelIndex &parent = QModelIndex()) const override
virtual QMimeData * | mimeData(const QModelIndexList &indexes) const override
virtual QStringList | mimeTypes() const override
virtual QModelIndex | parent(const QModelIndex &index) const override
virtual int | rowCount(const QModelIndex &parent = QModelIndex()) const override
virtual bool | setData(const QModelIndex &idx, const QVariant &value, int role = Qt::EditRole) override
virtual QModelIndex | sibling(int row, int column, const QModelIndex &idx) const override
virtual void | sort(int column, Qt::SortOrder order = Qt::AscendingOrder) override
virtual Qt::DropActions | supportedDropActions() const override

## Signals

void | directoryLoaded(const QString &path)
void | fileRenamed(const QString &path, const QString &oldName, const QString &newName)
void | rootPathChanged(const QString &newPath)

## Reimplemented Protected Functions

virtual bool | event(QEvent *event) override
virtual void | timerEvent(QTimerEvent *event) override

## Detailed Description

This class provides access to the local filesystem, providing functions for renaming and removing files and directories, and for creating new directories. In the simplest case, it can be used with a suitable display widget as part of a browser or filter.

QFileSystemModel can be accessed using the standard interface provided by QAbstractItemModel, but it also provides some convenience functions that are specific to a directory model. The fileInfo(), isDir(), fileName() and filePath() functions provide information about the underlying files and directories related to items in the model. Directories can be created and removed using mkdir(), rmdir().

Note: QFileSystemModel requires an instance of QApplication.

### Example Usage

A directory model that displays the contents of a default directory is usually constructed with a parent object:

          QFileSystemModel *model = new QFileSystemModel;
          model->setRootPath(QDir::currentPath());

A tree view can be used to display the contents of the model

          QTreeView *tree = new QTreeView(splitter);
          tree->setModel(model);

and the contents of a particular directory can be displayed by setting the tree view's root index:

          tree->setRootIndex(model->index(QDir::currentPath()));

The view's root index can be used to control how much of a hierarchical model is displayed. QFileSystemModel provides a convenience function that returns a suitable model index for a path to a directory within the model.

### Caching and Performance

QFileSystemModel will not fetch any files or directories until setRootPath() is called. This will prevent any unnecessary querying on the file system until that point such as listing the drives on Windows.

Unlike QDirModel, QFileSystemModel uses a separate thread to populate itself so it will not cause the main thread to hang as the file system is being queried. Calls to rowCount() will return 0 until the model populates a directory.

QFileSystemModel keeps a cache with file information. The cache is automatically kept up to date using the QFileSystemWatcher.

See also Model Classes.

## Member Type Documentation

### enum QFileSystemModel::Option
flags QFileSystemModel::Options

Constant | Value | Description
--- | --- | ---
`QFileSystemModel::DontWatchForChanges` | `0x00000001` | Do not add file watchers to the paths. This reduces overhead when using the model for simple tasks like line edit completion.
`QFileSystemModel::DontResolveSymlinks` | `0x00000002` | Don't resolve symlinks in the file system model. By default, symlinks are resolved.
`QFileSystemModel::DontUseCustomDirectoryIcons` | `0x00000004` | Always use the default directory icon. Some platforms allow the user to set a different icon. Custom icon lookup causes a big performance impact over network or removable drives. This sets the QFileIconProvider::DontUseCustomDirectoryIcons option in the icon provider accordingly.

This enum was introduced or modified in Qt 5.14.

The Options type is a typedef for QFlags<Option>. It stores an OR combination of Option values.

See also resolveSymlinks.

### enum QFileSystemModel::Roles

Constant | Value
--- | ---
`QFileSystemModel::FileIconRole` | `Qt::DecorationRole`
`QFileSystemModel::FilePathRole` | `Qt::UserRole + 1`
`QFileSystemModel::FileNameRole` | `Qt::UserRole + 2`
`QFileSystemModel::FilePermissions` | `Qt::UserRole + 3`

## Property Documentation

### nameFilterDisables : bool

This property holds whether files that don't pass the name filter are hidden or disabled

This property is `true` by default

Access functions:

bool | nameFilterDisables() const
void | setNameFilterDisables(bool enable)

### options : Options

This property holds the various options that affect the model

By default, all options are disabled.

Options should be set before changing properties.

This property was introduced in Qt 5.14.

Access functions:

QFileSystemModel::Options | options() const
void | setOptions(QFileSystemModel::Options options)

See also setOption() and testOption().

### readOnly : bool

This property holds whether the directory model allows writing to the file system

If this property is set to false, the directory model will allow renaming, copying and deleting of files and directories.

This property is `true` by default

Access functions:

bool | isReadOnly() const
void | setReadOnly(bool enable)

### resolveSymlinks : bool

This property holds whether the directory model should resolve symbolic links

This is only relevant on Windows.

By default, this property is `true`.

Access functions:

bool | resolveSymlinks() const
void | setResolveSymlinks(bool enable)

See also QFileSystemModel::Options.

## Member Function Documentation

### QFileSystemModel::QFileSystemModel(QObject *parent = nullptr)

Constructs a file system model with the given parent.

### `[signal]` void QFileSystemModel::directoryLoaded(const QString &path)

This signal is emitted when the gatherer thread has finished to load the path.

This function was introduced in Qt 4.7.

### `[signal]` void QFileSystemModel::fileRenamed(const QString &path, const QString &oldName, const QString &newName)

This signal is emitted whenever a file with the oldName is successfully renamed to newName. The file is located in in the directory path.

### `[signal]` void QFileSystemModel::rootPathChanged(const QString &newPath)

This signal is emitted whenever the root path has been changed to a newPath.

### `[virtual]` QFileSystemModel::~QFileSystemModel()

Destroys this file system model.

### `[override virtual]` bool QFileSystemModel::canFetchMore(const QModelIndex &parent) const

Reimplements: QAbstractItemModel::canFetchMore(const QModelIndex &parent) const.

### `[override virtual]` int QFileSystemModel::columnCount(const QModelIndex &parent = QModelIndex()) const

Reimplements: QAbstractItemModel::columnCount(const QModelIndex &parent) const.

### `[override virtual]` QVariant QFileSystemModel::data(const QModelIndex &index, int role = Qt::DisplayRole) const

Reimplements: QAbstractItemModel::data(const QModelIndex &index, int role) const.

See also setData().

### `[override virtual]` bool QFileSystemModel::dropMimeData(const QMimeData *data, Qt::DropAction action, int row, int column, const QModelIndex &parent)

Reimplements: QAbstractItemModel::dropMimeData(const QMimeData *data, Qt::DropAction action, int row, int column, const QModelIndex &parent).

Handles the data supplied by a drag and drop operation that ended with the given action over the row in the model specified by the row and column and by the parent index. Returns true if the operation was successful.

See also supportedDropActions().

### `[override virtual protected]` bool QFileSystemModel::event(QEvent *event)

Reimplements: QObject::event(QEvent *e).

### `[override virtual]` void QFileSystemModel::fetchMore(const QModelIndex &parent)

Reimplements: QAbstractItemModel::fetchMore(const QModelIndex &parent).

### QIcon QFileSystemModel::fileIcon(const QModelIndex &index) const

Returns the icon for the item stored in the model under the given index.

### QFileInfo QFileSystemModel::fileInfo(const QModelIndex &index) const

Returns the QFileInfo for the item stored in the model under the given index.

### QString QFileSystemModel::fileName(const QModelIndex &index) const

Returns the file name for the item stored in the model under the given index.

### QString QFileSystemModel::filePath(const QModelIndex &index) const

Returns the path of the item stored in the model under the index given.

### QDir::Filters QFileSystemModel::filter() const

Returns the filter specified for the directory model.

If a filter has not been set, the default filter is QDir::AllEntries | QDir::NoDotAndDotDot | QDir::AllDirs.

See also setFilter() and QDir::Filters.

### `[override virtual]` Qt::ItemFlags QFileSystemModel::flags(const QModelIndex &index) const

Reimplements: QAbstractItemModel::flags(const QModelIndex &index) const.

### `[override virtual]` bool QFileSystemModel::hasChildren(const QModelIndex &parent = QModelIndex()) const

Reimplements: QAbstractItemModel::hasChildren(const QModelIndex &parent) const.

### `[override virtual]` QVariant QFileSystemModel::headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const

Reimplements: QAbstractItemModel::headerData(int section, Qt::Orientation orientation, int role) const.

### QFileIconProvider *QFileSystemModel::iconProvider() const

Returns the file icon provider for this directory model.

See also setIconProvider().

### `[override virtual]` QModelIndex QFileSystemModel::index(int row, int column, const QModelIndex &parent = QModelIndex()) const

Reimplements: QAbstractItemModel::index(int row, int column, const QModelIndex &parent) const.

### QModelIndex QFileSystemModel::index(const QString &path, int column = 0) const

This is an overloaded function.

Returns the model item index for the given path and column.

### bool QFileSystemModel::isDir(const QModelIndex &index) const

Returns `true` if the model item index represents a directory; otherwise returns `false`.

### QDateTime QFileSystemModel::lastModified(const QModelIndex &index) const

Returns the date and time when index was last modified.

### `[override virtual]` QMimeData *QFileSystemModel::mimeData(const QModelIndexList &indexes) const

Reimplements: QAbstractItemModel::mimeData(const QModelIndexList &indexes) const.

Returns an object that contains a serialized description of the specified indexes. The format used to describe the items corresponding to the indexes is obtained from the mimeTypes() function.

If the list of indexes is empty, `nullptr` is returned rather than a serialized empty list.

### `[override virtual]` QStringList QFileSystemModel::mimeTypes() const

Reimplements: QAbstractItemModel::mimeTypes() const.

Returns a list of MIME types that can be used to describe a list of items in the model.

### QModelIndex QFileSystemModel::mkdir(const QModelIndex &parent, const QString &name)

Create a directory with the name in the parent model index.

### QVariant QFileSystemModel::myComputer(int role = Qt::DisplayRole) const

Returns the data stored under the given role for the item "My Computer".

See also Qt::ItemDataRole.

### QStringList QFileSystemModel::nameFilters() const

Returns a list of filters applied to the names in the model.

See also setNameFilters().

### `[override virtual]` QModelIndex QFileSystemModel::parent(const QModelIndex &index) const

Reimplements: QAbstractItemModel::parent(const QModelIndex &index) const.

### QFile::Permissions QFileSystemModel::permissions(const QModelIndex &index) const

Returns the complete OR-ed together combination of QFile::Permission for the index.

### bool QFileSystemModel::remove(const QModelIndex &index)

Removes the model item index from the file system model and deletes the corresponding file from the file system, returning true if successful. If the item cannot be removed, false is returned.

Warning: This function deletes files from the file system; it does not move them to a location where they can be recovered.

See also rmdir().

### bool QFileSystemModel::rmdir(const QModelIndex &index)

Removes the directory corresponding to the model item index in the file system model and deletes the corresponding directory from the file system, returning true if successful. If the directory cannot be removed, false is returned.

Warning: This function deletes directories from the file system; it does not move them to a location where they can be recovered.

See also remove().

### QDir QFileSystemModel::rootDirectory() const

The currently set directory

See also rootPath().

### QString QFileSystemModel::rootPath() const

The currently set root path

See also setRootPath() and rootDirectory().

### `[override virtual]` int QFileSystemModel::rowCount(const QModelIndex &parent = QModelIndex()) const

Reimplements: QAbstractItemModel::rowCount(const QModelIndex &parent) const.

### `[override virtual]` bool QFileSystemModel::setData(const QModelIndex &idx, const QVariant &value, int role = Qt::EditRole)

Reimplements: QAbstractItemModel::setData(const QModelIndex &index, const QVariant &value, int role).

See also data().

### void QFileSystemModel::setFilter(QDir::Filters filters)

Sets the directory model's filter to that specified by filters.

Note that the filter you set should always include the QDir::AllDirs enum value, otherwise QFileSystemModel won't be able to read the directory structure.

See also filter() and QDir::Filters.

### void QFileSystemModel::setIconProvider(QFileIconProvider *provider)

Sets the provider of file icons for the directory model.

See also iconProvider().

### void QFileSystemModel::setNameFilters(const QStringList &filters)

Sets the name filters to apply against the existing files.

See also nameFilters().

### void QFileSystemModel::setOption(QFileSystemModel::Option option, bool on = true)

Sets the given option to be enabled if on is true; otherwise, clears the given option.

Options should be set before changing properties.

This function was introduced in Qt 5.14.

See also options and testOption().

### QModelIndex QFileSystemModel::setRootPath(const QString &newPath)

Sets the directory that is being watched by the model to newPath by installing a file system watcher on it. Any changes to files and directories within this directory will be reflected in the model.

If the path is changed, the rootPathChanged() signal will be emitted.

Note: This function does not change the structure of the model or modify the data available to views. In other words, the "root" of the model is not changed to include only files and directories within the directory specified by newPath in the file system.

See also rootPath().

### `[override virtual]` QModelIndex QFileSystemModel::sibling(int row, int column, const QModelIndex &idx) const

Reimplements: QAbstractItemModel::sibling(int row, int column, const QModelIndex &index) const.

### qint64 QFileSystemModel::size(const QModelIndex &index) const

Returns the size in bytes of index. If the file does not exist, 0 is returned.

### `[override virtual]` void QFileSystemModel::sort(int column, Qt::SortOrder order = Qt::AscendingOrder)

Reimplements: QAbstractItemModel::sort(int column, Qt::SortOrder order).

### `[override virtual]` Qt::DropActions QFileSystemModel::supportedDropActions() const

Reimplements: QAbstractItemModel::supportedDropActions() const.

### bool QFileSystemModel::testOption(QFileSystemModel::Option option) const

Returns `true` if the given option is enabled; otherwise, returns false.

This function was introduced in Qt 5.14.

See also options and setOption().

### `[override virtual protected]` void QFileSystemModel::timerEvent(QTimerEvent *event)

Reimplements: QObject::timerEvent(QTimerEvent *event).

### QString QFileSystemModel::type(const QModelIndex &index) const

Returns the type of file index such as "Directory" or "JPEG file".