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# QItemDelegate Class Reference

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

    #include <QItemDelegate>

Inherits QAbstractItemDelegate.

- List of all members, including inherited members

### Writable Properties

- 1 writable property inherited from QObject

### Public Functions

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

- 8 public functions inherited from QAbstractItemDelegate
- 24 public functions inherited from QObject

### Public Slots

- 1 public slot inherited from QObject

### Signals

- 2 signals inherited from QAbstractItemDelegate
- 1 signal inherited from QObject

### Static Public Members

- 4 static public members inherited from QObject

### Protected Functions

- 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
- virtual bool eventFilter ( QObject * object, QEvent * event )

- 1 protected function inherited from QAbstractItemDelegate
- 9 protected functions 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.

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.

### 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.

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

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

Reimplemented from QAbstractItemDelegate.

See also QAbstractItemDelegate::editor().

### bool QItemDelegate::eventFilter ( QObject * object, QEvent * event ) `[virtual protected]`

If the object is the current editor: if the event is an Esc key press the current edit is cancelled and ended, or if the event is an Enter or Return key press the current edit is accepted and ended. If editing is ended the event filter returns true to signify that it has handled the event; in all other cases it does nothing and returns false to signify that the event hasn't been handled.

Reimplemented from QObject.

See also endEdit().

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

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

Reimplemented from QAbstractItemDelegate.

### void QItemDelegate::releaseEditor ( QWidget * editor ) `[virtual]`

Releases the editor.

Reimplemented from QAbstractItemDelegate.

See also QAbstractItemDelegate::releaseEditor().

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

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

Reimplemented from QAbstractItemDelegate.

### 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 QAbstractItemModel * model, const QModelIndex & index ) const `[virtual]`

Returns the size needed by the delegate to display the item specified by the model and item index, taking into account the visual information provided by the font metrics in fontMetrics, and the given style option.

Reimplemented from QAbstractItemDelegate.

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

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

Reimplemented from QAbstractItemDelegate.