QSortFilterProxyModel Class

The QSortFilterProxyModel class provides support for sorting and filtering data passed between another model and a view. More...

Header:	#include <QSortFilterProxyModel>
qmake:	QT += core
Since:	Qt 4.1
Inherits:	QAbstractProxyModel

• List of all members, including inherited members
• Obsolete members

Properties

dynamicSortFilter : bool filterCaseSensitivity : Qt::CaseSensitivity filterKeyColumn : int filterRegExp : QRegExp filterRegularExpression : QRegularExpression

filterRole : int isSortLocaleAware : bool recursiveFilteringEnabled : bool sortCaseSensitivity : Qt::CaseSensitivity sortRole : int

• 1 property inherited from QAbstractProxyModel
• 1 property inherited from QObject

Public Functions

	QSortFilterProxyModel(QObject *parent = nullptr)
virtual	~QSortFilterProxyModel()
bool	dynamicSortFilter() const
Qt::CaseSensitivity	filterCaseSensitivity() const
int	filterKeyColumn() const
QRegExp	filterRegExp() const
QRegularExpression	filterRegularExpression() const
int	filterRole() const
bool	isRecursiveFilteringEnabled() const
bool	isSortLocaleAware() const
void	setDynamicSortFilter(bool enable)
void	setFilterCaseSensitivity(Qt::CaseSensitivity cs)
void	setFilterKeyColumn(int column)
void	setFilterRole(int role)
void	setRecursiveFilteringEnabled(bool recursive)
void	setSortCaseSensitivity(Qt::CaseSensitivity cs)
void	setSortLocaleAware(bool on)
void	setSortRole(int role)
Qt::CaseSensitivity	sortCaseSensitivity() const
int	sortColumn() const
Qt::SortOrder	sortOrder() const
int	sortRole() const

Reimplemented Public Functions

virtual QModelIndex	buddy(const QModelIndex &index) const override
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 bool	insertColumns(int column, int count, const QModelIndex &parent = QModelIndex()) override
virtual bool	insertRows(int row, int count, const QModelIndex &parent = QModelIndex()) override
virtual QModelIndex	mapFromSource(const QModelIndex &sourceIndex) const override
virtual QItemSelection	mapSelectionFromSource(const QItemSelection &sourceSelection) const override
virtual QItemSelection	mapSelectionToSource(const QItemSelection &proxySelection) const override
virtual QModelIndex	mapToSource(const QModelIndex &proxyIndex) const override
virtual QModelIndexList	match(const QModelIndex &start, int role, const QVariant &value, int hits = 1, Qt::MatchFlags flags = Qt::MatchFlags(Qt::MatchStartsWith|Qt::MatchWrap)) const override
virtual QMimeData *	mimeData(const QModelIndexList &indexes) const override
virtual QStringList	mimeTypes() const override
virtual QModelIndex	parent(const QModelIndex &child) const override
virtual bool	removeColumns(int column, int count, const QModelIndex &parent = QModelIndex()) override
virtual bool	removeRows(int row, int count, const QModelIndex &parent = QModelIndex()) override
virtual int	rowCount(const QModelIndex &parent = QModelIndex()) const override
virtual bool	setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole) override
virtual bool	setHeaderData(int section, Qt::Orientation orientation, const QVariant &value, int role = Qt::EditRole) override
virtual void	setSourceModel(QAbstractItemModel *sourceModel) 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 QSize	span(const QModelIndex &index) const override
virtual Qt::DropActions	supportedDropActions() const override

• 28 public functions inherited from QAbstractProxyModel
• 40 public functions inherited from QAbstractItemModel
• 32 public functions inherited from QObject

Public Slots

void	invalidate()
void	setFilterFixedString(const QString &pattern)
void	setFilterRegExp(const QRegExp &regExp)
void	setFilterRegExp(const QString &pattern)
void	setFilterRegularExpression(const QString &pattern)
void	setFilterRegularExpression(const QRegularExpression &regularExpression)
void	setFilterWildcard(const QString &pattern)

• 2 public slots inherited from QAbstractItemModel
• 1 public slot inherited from QObject

Static Public Members

const QMetaObject

staticMetaObject

• 10 static public members inherited from QObject

Protected Functions

virtual bool	filterAcceptsColumn(int source_column, const QModelIndex &source_parent) const
virtual bool	filterAcceptsRow(int source_row, const QModelIndex &source_parent) const
void	invalidateFilter()
virtual bool	lessThan(const QModelIndex &source_left, const QModelIndex &source_right) const

• 19 protected functions inherited from QAbstractItemModel
• 9 protected functions inherited from QObject

Additional Inherited Members

• 1 signal inherited from QAbstractProxyModel
• 18 signals inherited from QAbstractItemModel
• 2 signals inherited from QObject
• 1 protected slot inherited from QAbstractProxyModel
• 1 protected slot inherited from QAbstractItemModel

Detailed Description

The QSortFilterProxyModel class provides support for sorting and filtering data passed between another model and a view.

QSortFilterProxyModel can be used for sorting items, filtering out items, or both. The model transforms the structure of a source model by mapping the model indexes it supplies to new indexes, corresponding to different locations, for views to use. This approach allows a given source model to be restructured as far as views are concerned without requiring any transformations on the underlying data, and without duplicating the data in memory.

Let's assume that we want to sort and filter the items provided by a custom model. The code to set up the model and the view, without sorting and filtering, would look like this:

        QTreeView *treeView = new QTreeView;
        MyItemModel *model = new MyItemModel(this);

        treeView->setModel(model);

To add sorting and filtering support to MyItemModel, we need to create a QSortFilterProxyModel, call setSourceModel() with the MyItemModel as argument, and install the QSortFilterProxyModel on the view:

        QTreeView *treeView = new QTreeView;
        MyItemModel *sourceModel = new MyItemModel(this);
        QSortFilterProxyModel *proxyModel = new QSortFilterProxyModel(this);

        proxyModel->setSourceModel(sourceModel);
        treeView->setModel(proxyModel);

At this point, neither sorting nor filtering is enabled; the original data is displayed in the view. Any changes made through the QSortFilterProxyModel are applied to the original model.

The QSortFilterProxyModel acts as a wrapper for the original model. If you need to convert source QModelIndexes to sorted/filtered model indexes or vice versa, use mapToSource(), mapFromSource(), mapSelectionToSource(), and mapSelectionFromSource().

Note: By default, the model dynamically re-sorts and re-filters data whenever the original model changes. This behavior can be changed by setting the dynamicSortFilter property.

The Basic Sort/Filter Model and Custom Sort/Filter Model examples illustrate how to use QSortFilterProxyModel to perform basic sorting and filtering and how to subclass it to implement custom behavior.

Sorting

QTableView and QTreeView have a sortingEnabled property that controls whether the user can sort the view by clicking the view's horizontal header. For example:

        treeView->setSortingEnabled(true);

When this feature is on (the default is off), clicking on a header section sorts the items according to that column. By clicking repeatedly, the user can alternate between ascending and descending order.

Behind the scene, the view calls the sort() virtual function on the model to reorder the data in the model. To make your data sortable, you can either implement sort() in your model, or use a QSortFilterProxyModel to wrap your model -- QSortFilterProxyModel provides a generic sort() reimplementation that operates on the sortRole() (Qt::DisplayRole by default) of the items and that understands several data types, including int, QString, and QDateTime. For hierarchical models, sorting is applied recursively to all child items. String comparisons are case sensitive by default; this can be changed by setting the sortCaseSensitivity property.

Custom sorting behavior is achieved by subclassing QSortFilterProxyModel and reimplementing lessThan(), which is used to compare items. For example:

bool MySortFilterProxyModel::lessThan(const QModelIndex &left,
                                      const QModelIndex &right) const
{
    QVariant leftData = sourceModel()->data(left);
    QVariant rightData = sourceModel()->data(right);

    if (leftData.type() == QVariant::DateTime) {
        return leftData.toDateTime() < rightData.toDateTime();
    } else {
        static const QRegularExpression emailPattern("[\\w\\.]*@[\\w\\.]*");

        QString leftString = leftData.toString();
        if (left.column() == 1) {
            const QRegularExpressionMatch match = emailPattern.match(leftString);
            if (match.hasMatch())
                leftString = match.captured(0);
        }
        QString rightString = rightData.toString();
        if (right.column() == 1) {
            const QRegularExpressionMatch match = emailPattern.match(rightString);
            if (match.hasMatch())
                rightString = match.captured(0);
        }

        return QString::localeAwareCompare(leftString, rightString) < 0;
    }
}

(This code snippet comes from the Custom Sort/Filter Model example.)

An alternative approach to sorting is to disable sorting on the view and to impose a certain order to the user. This is done by explicitly calling sort() with the desired column and order as arguments on the QSortFilterProxyModel (or on the original model if it implements sort()). For example:

        proxyModel->sort(2, Qt::AscendingOrder);

QSortFilterProxyModel can be sorted by column -1, in which case it returns to the sort order of the underlying source model.

Filtering

In addition to sorting, QSortFilterProxyModel can be used to hide items that do not match a certain filter. The filter is specified using a QRegExp object and is applied to the filterRole() (Qt::DisplayRole by default) of each item, for a given column. The QRegExp object can be used to match a regular expression, a wildcard pattern, or a fixed string. For example:

        proxyModel->setFilterRegExp(QRegExp(".png", Qt::CaseInsensitive,
                                            QRegExp::FixedString));
        proxyModel->setFilterKeyColumn(1);

For hierarchical models, the filter is applied recursively to all children. If a parent item doesn't match the filter, none of its children will be shown.

A common use case is to let the user specify the filter regular expression, wildcard pattern, or fixed string in a QLineEdit and to connect the textChanged() signal to setFilterRegularExpression(), setFilterWildcard(), or setFilterFixedString() to reapply the filter.

Custom filtering behavior can be achieved by reimplementing the filterAcceptsRow() and filterAcceptsColumn() functions. For example (from the Custom Sort/Filter Model example), the following implementation ignores the filterKeyColumn property and performs filtering on columns 0, 1, and 2:

bool MySortFilterProxyModel::filterAcceptsRow(int sourceRow,
        const QModelIndex &sourceParent) const
{
    QModelIndex index0 = sourceModel()->index(sourceRow, 0, sourceParent);
    QModelIndex index1 = sourceModel()->index(sourceRow, 1, sourceParent);
    QModelIndex index2 = sourceModel()->index(sourceRow, 2, sourceParent);

    return (sourceModel()->data(index0).toString().contains(filterRegExp())
            || sourceModel()->data(index1).toString().contains(filterRegExp()))
            && dateInRange(sourceModel()->data(index2).toDate());
}

(This code snippet comes from the Custom Sort/Filter Model example.)

If you are working with large amounts of filtering and have to invoke invalidateFilter() repeatedly, using reset() may be more efficient, depending on the implementation of your model. However, reset() returns the proxy model to its original state, losing selection information, and will cause the proxy model to be repopulated.

Subclassing

Since QAbstractProxyModel and its subclasses are derived from QAbstractItemModel, much of the same advice about subclassing normal models also applies to proxy models. In addition, it is worth noting that many of the default implementations of functions in this class are written so that they call the equivalent functions in the relevant source model. This simple proxying mechanism may need to be overridden for source models with more complex behavior; for example, if the source model provides a custom hasChildren() implementation, you should also provide one in the proxy model.

Note: Some general guidelines for subclassing models are available in the Model Subclassing Reference.

Note: With Qt 5, regular expression support has been improved through the QRegularExpression class. QSortFilterProxyModel dating back prior to that class creation, it originally supported only QRegExp. Since Qt 5.12, QRegularExpression APIs have been added. Therefore, QRegExp APIs should be considered deprecated and the QRegularExpression version should be used in place.

Warning: Don't mix calls to the getters and setters of different regexp types as this will lead to unexpected results. For maximum compatibility, the original implementation has been kept. Therefore, if, for example, a call to setFilterRegularExpression is made followed by another one to setFilterFixedString, the first call will setup a QRegularExpression object to use as filter while the second will setup a QRegExp in FixedString mode. However, this is an implementation detail that might change in the future.

See also QAbstractProxyModel, QAbstractItemModel, Model/View Programming, Basic Sort/Filter Model Example, Custom Sort/Filter Model Example, and QIdentityProxyModel.

Member Function Documentation

QSortFilterProxyModel::QSortFilterProxyModel(QObject *parent = nullptr)

Constructs a sorting filter model with the given parent.

[virtual] QSortFilterProxyModel::~QSortFilterProxyModel()

Destroys this sorting filter model.

[override virtual] QModelIndex QSortFilterProxyModel::buddy(const QModelIndex &index) const

Reimplemented from QAbstractProxyModel::buddy().

[override virtual] bool QSortFilterProxyModel::canFetchMore(const QModelIndex &parent) const

Reimplemented from QAbstractProxyModel::canFetchMore().

[override virtual] int QSortFilterProxyModel::columnCount(const QModelIndex &parent = QModelIndex()) const

Reimplemented from QAbstractItemModel::columnCount().

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

Reimplemented from QAbstractProxyModel::data().

See also setData().

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

Reimplemented from QAbstractProxyModel::dropMimeData().

[override virtual] void QSortFilterProxyModel::fetchMore(const QModelIndex &parent)

Reimplemented from QAbstractProxyModel::fetchMore().

[virtual protected] bool QSortFilterProxyModel::filterAcceptsColumn(int source_column, const QModelIndex &source_parent) const

Returns true if the item in the column indicated by the given source_column and source_parent should be included in the model; otherwise returns false.

The default implementation returns true if the value held by the relevant item matches the filter string, wildcard string or regular expression.

Note: By default, the Qt::DisplayRole is used to determine if the column should be accepted or not. This can be changed by setting the filterRole property.

See also filterAcceptsRow(), setFilterFixedString(), setFilterRegExp(), and setFilterWildcard().

[virtual protected] bool QSortFilterProxyModel::filterAcceptsRow(int source_row, const QModelIndex &source_parent) const

Returns true if the item in the row indicated by the given source_row and source_parent should be included in the model; otherwise returns false.

The default implementation returns true if the value held by the relevant item matches the filter string, wildcard string or regular expression.

Note: By default, the Qt::DisplayRole is used to determine if the row should be accepted or not. This can be changed by setting the filterRole property.

See also filterAcceptsColumn(), setFilterFixedString(), setFilterRegExp(), and setFilterWildcard().

[override virtual] Qt::ItemFlags QSortFilterProxyModel::flags(const QModelIndex &index) const

Reimplemented from QAbstractProxyModel::flags().

[override virtual] bool QSortFilterProxyModel::hasChildren(const QModelIndex &parent = QModelIndex()) const

Reimplemented from QAbstractProxyModel::hasChildren().

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

Reimplemented from QAbstractProxyModel::headerData().

See also setHeaderData().

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

Reimplemented from QAbstractItemModel::index().

[override virtual] bool QSortFilterProxyModel::insertColumns(int column, int count, const QModelIndex &parent = QModelIndex())

Reimplemented from QAbstractItemModel::insertColumns().

[override virtual] bool QSortFilterProxyModel::insertRows(int row, int count, const QModelIndex &parent = QModelIndex())

Reimplemented from QAbstractItemModel::insertRows().

[slot] void QSortFilterProxyModel::invalidate()

Invalidates the current sorting and filtering.

This function was introduced in Qt 4.3.

See also invalidateFilter().

[protected] void QSortFilterProxyModel::invalidateFilter()

Invalidates the current filtering.

This function should be called if you are implementing custom filtering (e.g. filterAcceptsRow()), and your filter parameters have changed.

This function was introduced in Qt 4.3.

See also invalidate().

[virtual protected] bool QSortFilterProxyModel::lessThan(const QModelIndex &source_left, const QModelIndex &source_right) const

Returns true if the value of the item referred to by the given index source_left is less than the value of the item referred to by the given index source_right, otherwise returns false.

This function is used as the < operator when sorting, and handles the following QVariant types:

• QMetaType::Int
• QMetaType::UInt
• QMetaType::LongLong
• QMetaType::ULongLong
• QMetaType::Float
• QMetaType::Double
• QMetaType::QChar
• QMetaType::QDate
• QMetaType::QTime
• QMetaType::QDateTime
• QMetaType::QString

Any other type will be converted to a QString using QVariant::toString().

Comparison of QStrings is case sensitive by default; this can be changed using the sortCaseSensitivity property.

By default, the Qt::DisplayRole associated with the QModelIndexes is used for comparisons. This can be changed by setting the sortRole property.

Note: The indices passed in correspond to the source model.

See also sortRole, sortCaseSensitivity, and dynamicSortFilter.

[override virtual] QModelIndex QSortFilterProxyModel::mapFromSource(const QModelIndex &sourceIndex) const

Reimplemented from QAbstractProxyModel::mapFromSource().

Returns the model index in the QSortFilterProxyModel given the sourceIndex from the source model.

See also mapToSource().

[override virtual] QItemSelection QSortFilterProxyModel::mapSelectionFromSource(const QItemSelection &sourceSelection) const

Reimplemented from QAbstractProxyModel::mapSelectionFromSource().

[override virtual] QItemSelection QSortFilterProxyModel::mapSelectionToSource(const QItemSelection &proxySelection) const

Reimplemented from QAbstractProxyModel::mapSelectionToSource().

[override virtual] QModelIndex QSortFilterProxyModel::mapToSource(const QModelIndex &proxyIndex) const

Reimplemented from QAbstractProxyModel::mapToSource().

Returns the source model index corresponding to the given proxyIndex from the sorting filter model.

See also mapFromSource().

[override virtual] QModelIndexList QSortFilterProxyModel::match(const QModelIndex &start, int role, const QVariant &value, int hits = 1, Qt::MatchFlags flags = Qt::MatchFlags(Qt::MatchStartsWith|Qt::MatchWrap)) const

Reimplemented from QAbstractItemModel::match().

[override virtual] QMimeData *QSortFilterProxyModel::mimeData(const QModelIndexList &indexes) const

Reimplemented from QAbstractProxyModel::mimeData().

[override virtual] QStringList QSortFilterProxyModel::mimeTypes() const

Reimplemented from QAbstractProxyModel::mimeTypes().

[override virtual] QModelIndex QSortFilterProxyModel::parent(const QModelIndex &child) const

Reimplemented from QAbstractItemModel::parent().

[override virtual] bool QSortFilterProxyModel::removeColumns(int column, int count, const QModelIndex &parent = QModelIndex())

Reimplemented from QAbstractItemModel::removeColumns().

[override virtual] bool QSortFilterProxyModel::removeRows(int row, int count, const QModelIndex &parent = QModelIndex())

Reimplemented from QAbstractItemModel::removeRows().

[override virtual] int QSortFilterProxyModel::rowCount(const QModelIndex &parent = QModelIndex()) const

Reimplemented from QAbstractItemModel::rowCount().

[override virtual] bool QSortFilterProxyModel::setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole)

Reimplemented from QAbstractProxyModel::setData().

See also data().

[slot] void QSortFilterProxyModel::setFilterFixedString(const QString &pattern)

Sets the fixed string used to filter the contents of the source model to the given pattern.

See also setFilterCaseSensitivity(), setFilterRegExp(), setFilterWildcard(), and filterRegExp().

[slot] void QSortFilterProxyModel::setFilterRegExp(const QString &pattern)

This is an overloaded function.

Sets the regular expression used to filter the contents of the source model to pattern.

Note: Setter function for property filterRegExp.

See also setFilterCaseSensitivity(), setFilterWildcard(), setFilterFixedString(), and filterRegExp().

[slot] void QSortFilterProxyModel::setFilterRegularExpression(const QString &pattern)

Sets the regular expression used to filter the contents of the source model to pattern.

This method should be preferred for new code as it will use QRegularExpression internally.

This function was introduced in Qt 5.12.

Note: Setter function for property filterRegularExpression.

See also setFilterCaseSensitivity(), setFilterWildcard(), setFilterFixedString(), and filterRegularExpression().

[slot] void QSortFilterProxyModel::setFilterWildcard(const QString &pattern)

Sets the wildcard expression used to filter the contents of the source model to the given pattern.

See also setFilterCaseSensitivity(), setFilterRegExp(), setFilterFixedString(), and filterRegExp().

[override virtual] bool QSortFilterProxyModel::setHeaderData(int section, Qt::Orientation orientation, const QVariant &value, int role = Qt::EditRole)

Reimplemented from QAbstractProxyModel::setHeaderData().

See also headerData().

[override virtual] void QSortFilterProxyModel::setSourceModel(QAbstractItemModel *sourceModel)

Reimplemented from QAbstractProxyModel::setSourceModel().

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

Reimplemented from QAbstractProxyModel::sibling().

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

Reimplemented from QAbstractProxyModel::sort().

int QSortFilterProxyModel::sortColumn() const

the column currently used for sorting

This returns the most recently used sort column.

This function was introduced in Qt 4.5.

Qt::SortOrder QSortFilterProxyModel::sortOrder() const

the order currently used for sorting

This returns the most recently used sort order.

This function was introduced in Qt 4.5.

[override virtual] QSize QSortFilterProxyModel::span(const QModelIndex &index) const

Reimplemented from QAbstractProxyModel::span().

[override virtual] Qt::DropActions QSortFilterProxyModel::supportedDropActions() const

Reimplemented from QAbstractProxyModel::supportedDropActions().