Qt 4.0: QItemDelegate Class Reference

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# QItemDelegate Class Reference
[QtGui module]

The QItemDelegate class provides display and editing facilities for data items from a model. More...

    #include <QItemDelegate>

Inherits QAbstractItemDelegate.

Inherited by QSqlRelationalDelegate.

- List of all members, including inherited members

### Public Functions

- QItemDelegate ( QObject * parent = 0 )
- ~QItemDelegate ()
- virtual QWidget * createEditor ( QWidget * parent, const QStyleOptionViewItem & option, const QModelIndex & index ) const
- QItemEditorFactory * itemEditorFactory () const
- virtual void paint ( QPainter * painter, const QStyleOptionViewItem & option, const QModelIndex & index ) const
- virtual void setEditorData ( QWidget * editor, const QModelIndex & index ) const
- void setItemEditorFactory ( QItemEditorFactory * factory )
- virtual void setModelData ( QWidget * editor, QAbstractItemModel * model, const QModelIndex & index ) const
- virtual QSize sizeHint ( const QStyleOptionViewItem & option, const QModelIndex & index ) const
- virtual void updateEditorGeometry ( QWidget * editor, const QStyleOptionViewItem & option, const QModelIndex & index ) const

- 7 public functions inherited from QAbstractItemDelegate
- 28 public functions inherited from QObject

### Protected Functions

- virtual void drawCheck ( QPainter * painter, const QStyleOptionViewItem & option, const QRect & rect, Qt::CheckState state ) const
- virtual void drawDecoration ( QPainter * painter, const QStyleOptionViewItem & option, const QRect & rect, const QPixmap & pixmap ) const
- virtual void drawDisplay ( QPainter * painter, const QStyleOptionViewItem & option, const QRect & rect, const QString & text ) const
- virtual void drawFocus ( QPainter * painter, const QStyleOptionViewItem & option, const QRect & rect ) const

- 7 protected functions inherited from QObject

### Additional Inherited Members

- 1 property inherited from QObject
- 1 public slot inherited from QObject
- 2 signals inherited from QAbstractItemDelegate
- 1 signal inherited from QObject
- 1 static public member inherited from QAbstractItemDelegate
- 4 static public members inherited from QObject

## Detailed Description

The QItemDelegate class provides display and editing facilities for data items from a model.

A QItemDelegate can be used to provide an editor for an item view class that is subclassed from QAbstractItemView. Using a delegate for this purpose allows the editing mechanism to be customized and developed independently from the model and view.

The QItemDelegate class is one of the Model/View Classes and is part of Qt's model/view framework.

Delegates can be used to manipulate data in two complementary ways: by processing events in the normal manner, or by implementing a custom editor widget. The item delegate takes the approach of providing a widget for editing purposes that can be supplied to QAbstractItemView::setDelegate() or the equivalent function in subclasses of QAbstractItemView.

This class demonstrates how to implement the functions for painting the delegate, and editing data from the model. The paint() and sizeHint() virtual functions defined in QAbstractItemDelegate are implemented to ensure that the delegate is presented correctly. Only the standard editing functions for widget-based delegates are reimplemented here: editor() returns the widget used to change data from the model; setEditorData() provides the widget with data to manipulate; updateEditorGeometry() ensures that the editor is displayed correctly with respect to the item view; setModelData() returns the updated data to the model; releaseEditor() indicates that the user has completed editing the data, and that the editor widget can be destroyed.

See also Model/View Programming and QAbstractItemDelegate.

## Member Function Documentation

### QItemDelegate::QItemDelegate ( QObject * parent = 0 )

Constructs an item delegate with the given parent.

### QItemDelegate::~QItemDelegate ()

Destroys the item delegate.

### QWidget * QItemDelegate::createEditor ( QWidget * parent, const QStyleOptionViewItem & option, const QModelIndex & index ) const `[virtual]`

Returns the widget used to edit the item specified by index for editing. The parent widget and style option are used to control how the editor widget appears.

Reimplemented from QAbstractItemDelegate.

See also QAbstractItemDelegate::createEditor().

### void QItemDelegate::drawCheck ( QPainter * painter, const QStyleOptionViewItem & option, const QRect & rect, Qt::CheckState state ) const `[virtual protected]`

Renders a check indicator within the rectangle specified by rect, using the given painter and style option, using the given state.

### void QItemDelegate::drawDecoration ( QPainter * painter, const QStyleOptionViewItem & option, const QRect & rect, const QPixmap & pixmap ) const `[virtual protected]`

Renders the decoration pixmap within the rectangle specified by rect using the given painter and style option.

### void QItemDelegate::drawDisplay ( QPainter * painter, const QStyleOptionViewItem & option, const QRect & rect, const QString & text ) const `[virtual protected]`

Renders the item view text within the rectangle specified by rect using the given painter and style option.

### void QItemDelegate::drawFocus ( QPainter * painter, const QStyleOptionViewItem & option, const QRect & rect ) const `[virtual protected]`

Renders the region within the rectangle specified by rect, indicating that it has the focus, using the given painter and style option.

### QItemEditorFactory * QItemDelegate::itemEditorFactory () const

Returns the editor factory used by the item delegate. If no editor factory is set, the function will return null.

See also setItemEditorFactory().

### void QItemDelegate::paint ( QPainter * painter, const QStyleOptionViewItem & option, const QModelIndex & index ) const `[virtual]`

Renders the delegate using the given painter and style option for the item specified by index.

Reimplemented from QAbstractItemDelegate.

### void QItemDelegate::setEditorData ( QWidget * editor, const QModelIndex & index ) const `[virtual]`

Sets the data to be displayed and edited by the editor for the item specified by index.

Reimplemented from QAbstractItemDelegate.

### void QItemDelegate::setItemEditorFactory ( QItemEditorFactory * factory )

Sets the editor factory to be used by the item delegate to be the factory specified. If no editor factory is set, the item delegate will use the default editor factory.

See also itemEditorFactory().

### void QItemDelegate::setModelData ( QWidget * editor, QAbstractItemModel * model, const QModelIndex & index ) const `[virtual]`

Sets the data for the specified model and item index from that supplied by the editor.

Reimplemented from QAbstractItemDelegate.

### QSize QItemDelegate::sizeHint ( const QStyleOptionViewItem & option, const QModelIndex & index ) const `[virtual]`

Returns the size needed by the delegate to display the item specified by index, taking into account the style information provided by option.

Reimplemented from QAbstractItemDelegate.

### void QItemDelegate::updateEditorGeometry ( QWidget * editor, const QStyleOptionViewItem & option, const QModelIndex & index ) const `[virtual]`

Updates the editor for the item specified by index according to the style option given.

Reimplemented from QAbstractItemDelegate.