QItemDelegate Class

Member Function Documentation

QItemDelegate::QItemDelegate(QObject *parent = nullptr)

Constructs an item delegate with the given parent.

[virtual] QItemDelegate::~QItemDelegate()

Destroys the item delegate.

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

Reimplemented from QAbstractItemDelegate::createEditor().

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.

See also QAbstractItemDelegate::createEditor().

[protected] void QItemDelegate::drawBackground(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const

Renders the item background for the given index, using the given painter and style option.

This function was introduced in Qt 4.2.

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

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

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

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

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

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

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

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

[override virtual protected] bool QItemDelegate::editorEvent(QEvent *event, QAbstractItemModel *model, const QStyleOptionViewItem &option, const QModelIndex &index)

Reimplemented from QAbstractItemDelegate::editorEvent().

[override virtual protected] bool QItemDelegate::eventFilter(QObject *editor, QEvent *event)

Reimplemented from QObject::eventFilter().

Returns true if the given editor is a valid QWidget and the given event is handled; otherwise returns false. The following key press events are handled by default:

• Tab
• Backtab
• Enter
• Return
• Esc

In the case of Tab, Backtab, Enter and Return key press events, the editor's data is committed to the model and the editor is closed. If the event is a Tab key press the view will open an editor on the next item in the view. Likewise, if the event is a Backtab key press the view will open an editor on the previous item in the view.

If the event is a Esc key press event, the editor is closed without committing its data.

See also commitData() and closeEditor().

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().

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

Reimplemented from QAbstractItemDelegate::paint().

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

When reimplementing this function in a subclass, you should update the area held by the option's rect variable, using the option's state variable to determine the state of the item to be displayed, and adjust the way it is painted accordingly.

For example, a selected item may need to be displayed differently to unselected items, as shown in the following code:

    if (option.state & QStyle::State_Selected)
        painter->fillRect(option.rect, option.palette.highlight());

    int size = qMin(option.rect.width(), option.rect.height());
    int brightness = index.model()->data(index, Qt::DisplayRole).toInt();
    double radius = (size / 2.0) - (brightness / 255.0 * size / 2.0);
    if (radius == 0.0)
        return;

    painter->save();
    painter->setRenderHint(QPainter::Antialiasing, true);
    painter->setPen(Qt::NoPen);
    if (option.state & QStyle::State_Selected)
        painter->setBrush(option.palette.highlightedText());
    else
    ...

After painting, you should ensure that the painter is returned to its the state it was supplied in when this function was called. For example, it may be useful to call QPainter::save() before painting and QPainter::restore() afterwards.

See also QStyle::State.

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

Reimplemented from QAbstractItemDelegate::setEditorData().

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

The default implementation stores the data in the editor widget's user property.

See also QMetaProperty::isUser().

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().

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

Reimplemented from QAbstractItemDelegate::setModelData().

Gets data from the editor widget and stores it in the specified model at the item index.

The default implementation gets the value to be stored in the data model from the editor widget's user property.

See also QMetaProperty::isUser().

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

Reimplemented from QAbstractItemDelegate::sizeHint().

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

When reimplementing this function, note that in case of text items, QItemDelegate adds a margin (i.e. 2 * QStyle::PM_FocusFrameHMargin) to the length of the text.

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

Reimplemented from QAbstractItemDelegate::updateEditorGeometry().

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