com.trolltech.qt.gui
Class QSortFilterProxyModel

java.lang.Object
  extended by com.trolltech.qt.internal.QSignalEmitterInternal
      extended by com.trolltech.qt.QSignalEmitter
          extended by com.trolltech.qt.QtJambiObject
              extended by com.trolltech.qt.core.QObject
                  extended by com.trolltech.qt.core.QAbstractItemModel
                      extended by com.trolltech.qt.gui.QAbstractProxyModel
                          extended by com.trolltech.qt.gui.QSortFilterProxyModel
All Implemented Interfaces:
QtJambiInterface

public class QSortFilterProxyModel
extends QAbstractProxyModel

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 does not dynamically re-sort and re-filter 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 you 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:

The following code example is written in c++.

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 {
        QRegExp *emailPattern = new QRegExp("([\\w\\.]*@[\\w\\.]*)");

        QString leftString = leftData.toString();
        if(left.column() == 1 && emailPattern->indexIn(leftString) != -1)
            leftString = emailPattern->cap(1);

        QString rightString = rightData.toString();
        if(right.column() == 1 && emailPattern->indexIn(rightString) != -1)
            rightString = emailPattern->cap(1);

        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.SortOrder.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 don't 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(new QRegExp(".png", Qt.CaseSensitivity.CaseInsensitive,
                                            QRegExp.PatternSyntax.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 regexp, wildcard pattern, or fixed string in a QLineEdit and to connect the textChanged() signal to setFilterRegExp(), setFilterWildcard(), or setFilterFixedString() to reapply the filter.

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

The following code example is written in c++.

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, note that reset() returns the proxy model to its original state, losing selection information, and will cause the proxy model to be repopulated.

Subclassing

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

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.

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


Nested Class Summary
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
QSignalEmitter.AbstractSignal, QSignalEmitter.PrivateSignal0, QSignalEmitter.PrivateSignal1, QSignalEmitter.PrivateSignal2, QSignalEmitter.PrivateSignal3, QSignalEmitter.PrivateSignal4, QSignalEmitter.PrivateSignal5, QSignalEmitter.PrivateSignal6, QSignalEmitter.PrivateSignal7, QSignalEmitter.PrivateSignal8, QSignalEmitter.PrivateSignal9, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9
 
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal
 
Field Summary
 
Fields inherited from class com.trolltech.qt.core.QAbstractItemModel
columnsAboutToBeInserted, columnsAboutToBeRemoved, columnsInserted, columnsRemoved, dataChanged, headerDataChanged, layoutAboutToBeChanged, layoutChanged, modelAboutToBeReset, modelReset, rowsAboutToBeInserted, rowsAboutToBeRemoved, rowsInserted, rowsRemoved
 
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
currentSender
 
Constructor Summary
QSortFilterProxyModel()
          Constructs a sorting filter model with the given parent.
QSortFilterProxyModel(QObject parent)
          Constructs a sorting filter model with the given parent.
 
Method Summary
 boolean dynamicSortFilter()
          This property holds whether the proxy model is dynamically sorted and filtered whenever the contents of the source model change.
protected  boolean filterAcceptsColumn(int source_column, com.trolltech.qt.core.QModelIndex source_parent)
          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.
protected  boolean filterAcceptsRow(int source_row, com.trolltech.qt.core.QModelIndex source_parent)
          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.
 Qt.CaseSensitivity filterCaseSensitivity()
          This property holds the case sensitivity of the QRegExp pattern used to filter the contents of the source model.
 int filterKeyColumn()
          This property holds the column where the key used to filter the contents of the source model is read from.
 QRegExp filterRegExp()
          This property holds the QRegExp used to filter the contents of the source model.
 int filterRole()
          This property holds the item role that is used to query the source model's data when filtering items.
 void invalidate()
          Invalidates the current sorting and filtering.
protected  void invalidateFilter()
          Invalidates the current filtering.
 boolean isSortLocaleAware()
          This property holds the local aware setting used for comparing strings when sorting.
protected  boolean lessThan(com.trolltech.qt.core.QModelIndex left, com.trolltech.qt.core.QModelIndex right)
          Returns true if the value of the item referred to by the given index left is less than the value of the item referred to by the given index right, otherwise returns false.
 void setDynamicSortFilter(boolean enable)
          This property holds whether the proxy model is dynamically sorted and filtered whenever the contents of the source model change.
 void setFilterCaseSensitivity(Qt.CaseSensitivity cs)
          This property holds the case sensitivity of the QRegExp pattern used to filter the contents of the source model.
 void setFilterFixedString(java.lang.String pattern)
          Sets the fixed string used to filter the contents of the source model to the given pattern.
 void setFilterKeyColumn(int column)
          This property holds the column where the key used to filter the contents of the source model is read from.
 void setFilterRegExp(QRegExp regExp)
          This property holds the QRegExp used to filter the contents of the source model.
 void setFilterRegExp(java.lang.String pattern)
          This property holds the QRegExp used to filter the contents of the source model.
 void setFilterRole(int role)
          This property holds the item role that is used to query the source model's data when filtering items.
 void setFilterWildcard(java.lang.String pattern)
          Sets the wildcard expression used to filter the contents of the source model to the given pattern.
 void setSortCaseSensitivity(Qt.CaseSensitivity cs)
          This property holds the case sensitivity setting used for comparing strings when sorting.
 void setSortLocaleAware(boolean on)
          This property holds the local aware setting used for comparing strings when sorting.
 void setSortRole(int role)
          This property holds the item role that is used to query the source model's data when sorting items.
 Qt.CaseSensitivity sortCaseSensitivity()
          This property holds the case sensitivity setting used for comparing strings when sorting.
 int sortColumn()
          the column currently used for sorting This returns the most recently used sort column.
 Qt.SortOrder sortOrder()
          the order currently used for sorting This returns the most recently used sort order.
 int sortRole()
          This property holds the item role that is used to query the source model's data when sorting items.
 
Methods inherited from class com.trolltech.qt.gui.QAbstractProxyModel
mapFromSource, mapSelectionFromSource, mapSelectionToSource, mapToSource, setSourceModel, sourceModel
 
Methods inherited from class com.trolltech.qt.core.QAbstractItemModel
beginInsertColumns, beginInsertRows, beginRemoveColumns, beginRemoveRows, buddy, canFetchMore, changePersistentIndex, changePersistentIndexList, columnCount, columnCount, createIndex, createIndex, createIndex, data, data, data, data, dropMimeData, endInsertColumns, endInsertRows, endRemoveColumns, endRemoveRows, fetchMore, flags, hasChildren, hasChildren, hasIndex, hasIndex, headerData, headerData, index, index, insertColumn, insertColumn, insertColumns, insertColumns, insertRow, insertRow, insertRows, insertRows, itemData, match, match, match, match, mimeData, mimeTypes, parent, persistentIndexList, removeColumn, removeColumn, removeColumns, removeColumns, removeRow, removeRow, removeRows, removeRows, reset, revert, rowCount, rowCount, setData, setData, setData, setData, setHeaderData, setHeaderData, setItemData, setSupportedDragActions, setSupportedDragActions, sibling, sort, sort, span, submit, supportedDragActions, supportedDropActions
 
Methods inherited from class com.trolltech.qt.core.QObject
childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, event, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, indexOfProperty, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, properties, property, removeEventFilter, setObjectName, setParent, setProperty, startTimer, timerEvent, toString, userProperty
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread
 
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
__qt_signalInitialization
 
Methods inherited from class java.lang.Object
clone, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Constructor Detail

QSortFilterProxyModel

public QSortFilterProxyModel()
Constructs a sorting filter model with the given parent.


QSortFilterProxyModel

public QSortFilterProxyModel(QObject parent)
Constructs a sorting filter model with the given parent.

Method Detail

dynamicSortFilter

public final boolean dynamicSortFilter()
This property holds whether the proxy model is dynamically sorted and filtered whenever the contents of the source model change. The default value is false.


filterCaseSensitivity

public final Qt.CaseSensitivity filterCaseSensitivity()
This property holds the case sensitivity of the QRegExp pattern used to filter the contents of the source model. By default, the filter is case sensitive.

See also:
filterRegExp, and sortCaseSensitivity.


filterKeyColumn

public final int filterKeyColumn()
This property holds the column where the key used to filter the contents of the source model is read from. The default value is 0. If the value is -1, the keys will be read from all columns.


filterRegExp

public final QRegExp filterRegExp()
This property holds the QRegExp used to filter the contents of the source model. Setting this property overwrites the current filterCaseSensitivity. By default, the QRegExp is an empty string matching all contents.

See also:
filterCaseSensitivity, setFilterWildcard(), and setFilterFixedString().


filterRole

public final int filterRole()
This property holds the item role that is used to query the source model's data when filtering items. The default value is Qt::DisplayRole .

See also:
filterAcceptsRow().


invalidate

public final void invalidate()
Invalidates the current sorting and filtering.

See also:
invalidateFilter().


invalidateFilter

protected final void 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.

See also:
invalidate().


isSortLocaleAware

public final boolean isSortLocaleAware()
This property holds the local aware setting used for comparing strings when sorting. By default, sorting is not local aware.

See also:
sortCaseSensitivity, and lessThan().


setDynamicSortFilter

public final void setDynamicSortFilter(boolean enable)
This property holds whether the proxy model is dynamically sorted and filtered whenever the contents of the source model change. The default value is false.


setFilterCaseSensitivity

public final void setFilterCaseSensitivity(Qt.CaseSensitivity cs)
This property holds the case sensitivity of the QRegExp pattern used to filter the contents of the source model. By default, the filter is case sensitive.

See also:
filterRegExp, and sortCaseSensitivity.


setFilterFixedString

public final void setFilterFixedString(java.lang.String 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().


setFilterKeyColumn

public final void setFilterKeyColumn(int column)
This property holds the column where the key used to filter the contents of the source model is read from. The default value is 0. If the value is -1, the keys will be read from all columns.


setFilterRegExp

public final void setFilterRegExp(QRegExp regExp)
This property holds the QRegExp used to filter the contents of the source model. Setting this property overwrites the current filterCaseSensitivity. By default, the QRegExp is an empty string matching all contents.

See also:
filterCaseSensitivity, setFilterWildcard(), and setFilterFixedString().


setFilterRegExp

public final void setFilterRegExp(java.lang.String pattern)
This property holds the QRegExp used to filter the contents of the source model. Setting this property overwrites the current filterCaseSensitivity. By default, the QRegExp is an empty string matching all contents.

See also:
filterCaseSensitivity, setFilterWildcard(), and setFilterFixedString().


setFilterRole

public final void setFilterRole(int role)
This property holds the item role that is used to query the source model's data when filtering items. The default value is Qt::DisplayRole .

See also:
filterAcceptsRow().


setFilterWildcard

public final void setFilterWildcard(java.lang.String 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().


setSortCaseSensitivity

public final void setSortCaseSensitivity(Qt.CaseSensitivity cs)
This property holds the case sensitivity setting used for comparing strings when sorting. By default, sorting is case sensitive.

See also:
filterCaseSensitivity, and lessThan().


setSortLocaleAware

public final void setSortLocaleAware(boolean on)
This property holds the local aware setting used for comparing strings when sorting. By default, sorting is not local aware.

See also:
sortCaseSensitivity, and lessThan().


setSortRole

public final void setSortRole(int role)
This property holds the item role that is used to query the source model's data when sorting items. The default value is Qt::DisplayRole .

See also:
lessThan().


sortCaseSensitivity

public final Qt.CaseSensitivity sortCaseSensitivity()
This property holds the case sensitivity setting used for comparing strings when sorting. By default, sorting is case sensitive.

See also:
filterCaseSensitivity, and lessThan().


sortColumn

public final int sortColumn()
the column currently used for sorting This returns the most recently used sort column.


sortOrder

public final Qt.SortOrder sortOrder()
the order currently used for sorting This returns the most recently used sort order.


sortRole

public final int sortRole()
This property holds the item role that is used to query the source model's data when sorting items. The default value is Qt::DisplayRole .

See also:
lessThan().


filterAcceptsColumn

protected boolean filterAcceptsColumn(int source_column,
                                      com.trolltech.qt.core.QModelIndex source_parent)
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 row should be accepted or not. This can be changed by setting the filterRole property.

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


filterAcceptsRow

protected boolean filterAcceptsRow(int source_row,
                                   com.trolltech.qt.core.QModelIndex source_parent)
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().


lessThan

protected boolean lessThan(com.trolltech.qt.core.QModelIndex left,
                           com.trolltech.qt.core.QModelIndex right)
Returns true if the value of the item referred to by the given index left is less than the value of the item referred to by the given index right, otherwise returns false.

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

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.