QGraphicsProxyWidget Class

QGraphicsProxyWidget embeds QWidget-based widgets, for example, a QPushButton, QFontComboBox, or even QFileDialog, into QGraphicsScene. It forwards events between the two objects and translates between QWidget's integer-based geometry and QGraphicsWidget's qreal-based geometry. QGraphicsProxyWidget supports all core features of QWidget, including tab focus, keyboard input, Drag & Drop, and popups. You can also embed complex widgets, e.g., widgets with subwidgets.

Example:

int main(int argc, char **argv)
{
    QApplication app(argc, argv);

    QTabWidget *tabWidget = new QTabWidget;

    QGraphicsScene scene;
    QGraphicsProxyWidget *proxy = scene.addWidget(tabWidget);

    QGraphicsView view(&scene);
    view.show();

    return app.exec();
}

QGraphicsProxyWidget takes care of automatically embedding popup children of embedded widgets through creating a child proxy for each popup. This means that when an embedded QComboBox shows its popup list, a new QGraphicsProxyWidget is created automatically, embedding the popup, and positioning it correctly. This only works if the popup is child of the embedded widget (for example QToolButton::setMenu() requires the QMenu instance to be child of the QToolButton).

Embedding a Widget with QGraphicsProxyWidget▲

There are two ways to embed a widget using QGraphicsProxyWidget. The most common way is to pass a widget pointer to QGraphicsScene::addWidget() together with any relevant Qt::WindowFlags. This function returns a pointer to a QGraphicsProxyWidget. You can then choose to reparent or position either the proxy, or the embedded widget itself.

For example, in the code snippet below, we embed a group box into the proxy:

 

Sélectionnez

QGroupBox *groupBox = new QGroupBox("Contact Details");
QLabel *numberLabel = new QLabel("Telephone number");
QLineEdit *numberEdit = new QLineEdit;

QFormLayout *layout = new QFormLayout;
layout->addRow(numberLabel, numberEdit);
groupBox->setLayout(layout);

QGraphicsScene scene;
QGraphicsProxyWidget *proxy = scene.addWidget(groupBox);

QGraphicsView view(&scene);
view.show();

The image below is the output obtained with its contents margin and contents rect labeled.

Alternatively, you can start by creating a new QGraphicsProxyWidget item, and then call setWidget() to embed a QWidget later. The widget() function returns a pointer to the embedded widget. QGraphicsProxyWidget shares ownership with QWidget, so if either of the two widgets are destroyed, the other widget will be automatically destroyed as well.

Synchronizing Widget States▲

QGraphicsScene scene;

QLineEdit *edit = new QLineEdit;
QGraphicsProxyWidget *proxy = scene.addWidget(edit);

edit->isVisible();  // returns true
proxy->isVisible(); // also returns true

edit->hide();

edit->isVisible();  // returns false
proxy->isVisible(); // also returns false

See Also▲

enum QGraphicsProxyWidget::anonymous▲

QGraphicsProxyWidget::QGraphicsProxyWidget(QGraphicsItem *parent = nullptr, Qt::WindowFlags wFlags = Qt::WindowFlags())▲

[virtual] QGraphicsProxyWidget::~QGraphicsProxyWidget()▲

[override virtual protected] void QGraphicsProxyWidget::contextMenuEvent(QGraphicsSceneContextMenuEvent *event)▲

QGraphicsProxyWidget *QGraphicsProxyWidget::createProxyForChildWidget(QWidget *child)▲

[override virtual protected] void QGraphicsProxyWidget::dragEnterEvent(QGraphicsSceneDragDropEvent *event)▲

[override virtual protected] void QGraphicsProxyWidget::dragLeaveEvent(QGraphicsSceneDragDropEvent *event)▲

[override virtual protected] void QGraphicsProxyWidget::dragMoveEvent(QGraphicsSceneDragDropEvent *event)▲

[override virtual protected] void QGraphicsProxyWidget::dropEvent(QGraphicsSceneDragDropEvent *event)▲

[override virtual protected] bool QGraphicsProxyWidget::event(QEvent *event)▲

[override virtual protected] bool QGraphicsProxyWidget::eventFilter(QObject *object, QEvent *event)▲

[override virtual protected] void QGraphicsProxyWidget::focusInEvent(QFocusEvent *event)▲

[override virtual protected] bool QGraphicsProxyWidget::focusNextPrevChild(bool next)▲

[override virtual protected] void QGraphicsProxyWidget::focusOutEvent(QFocusEvent *event)▲

[override virtual protected] void QGraphicsProxyWidget::grabMouseEvent(QEvent *event)▲

[override virtual protected] void QGraphicsProxyWidget::hideEvent(QHideEvent *event)▲

[override virtual protected] void QGraphicsProxyWidget::hoverEnterEvent(QGraphicsSceneHoverEvent *event)▲

[override virtual protected] void QGraphicsProxyWidget::hoverLeaveEvent(QGraphicsSceneHoverEvent *event)▲

[override virtual protected] void QGraphicsProxyWidget::hoverMoveEvent(QGraphicsSceneHoverEvent *event)▲

[override virtual protected] void QGraphicsProxyWidget::inputMethodEvent(QInputMethodEvent *event)▲

[override virtual protected] QVariant QGraphicsProxyWidget::inputMethodQuery(Qt::InputMethodQuery query) const▲

[override virtual protected] QVariant QGraphicsProxyWidget::itemChange(QGraphicsItem::GraphicsItemChange change, const QVariant &value)▲

[override virtual protected] void QGraphicsProxyWidget::keyPressEvent(QKeyEvent *event)▲

[override virtual protected] void QGraphicsProxyWidget::keyReleaseEvent(QKeyEvent *event)▲

[override virtual protected] void QGraphicsProxyWidget::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event)▲

[override virtual protected] void QGraphicsProxyWidget::mouseMoveEvent(QGraphicsSceneMouseEvent *event)▲

[override virtual protected] void QGraphicsProxyWidget::mousePressEvent(QGraphicsSceneMouseEvent *event)▲

[override virtual protected] void QGraphicsProxyWidget::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)▲

[protected] QGraphicsProxyWidget *QGraphicsProxyWidget::newProxyWidget(const QWidget *child)▲

[override virtual] void QGraphicsProxyWidget::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)▲

[override virtual protected] void QGraphicsProxyWidget::resizeEvent(QGraphicsSceneResizeEvent *event)▲

[override virtual] void QGraphicsProxyWidget::setGeometry(const QRectF &rect)▲

void QGraphicsProxyWidget::setWidget(QWidget *widget)▲

[override virtual protected] void QGraphicsProxyWidget::showEvent(QShowEvent *event)▲

[override virtual protected] QSizeF QGraphicsProxyWidget::sizeHint(Qt::SizeHint which, const QSizeF &constraint = QSizeF()) const▲

QRectF QGraphicsProxyWidget::subWidgetRect(const QWidget *widget) const▲

[override virtual] int QGraphicsProxyWidget::type() const▲

[override virtual protected] void QGraphicsProxyWidget::ungrabMouseEvent(QEvent *event)▲

[override virtual protected] void QGraphicsProxyWidget::wheelEvent(QGraphicsSceneWheelEvent *event)▲

QWidget *QGraphicsProxyWidget::widget() const▲