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Sourcecode: qt4-x11 version File versions

void QGraphicsScene::addItem ( QGraphicsItem item  ) 

Adds or moves the item item and all its childen to the scene.

If the item is visible (i.e., QGraphicsItem::isVisible() returns true), QGraphicsScene will emit changed() once control goes back to the event loop.

If the item is already in a different scene, it will first be removed from its old scene, and then added to this scene as a top-level.

QGraphicsScene will send ItemSceneChange notifications to item while it is added to the scene. If item does not currently belong to a scene, only one notification is sent. If it does belong to scene already (i.e., it is moved to this scene), QGraphicsScene will send an addition notification as the item is removed from its previous scene.

See also:
removeItem(), addEllipse(), addLine(), addPath(), addPixmap(), addRect(), addText(), addWidget()

Definition at line 2110 of file qgraphicsscene.cpp.

References addItem(), QGraphicsItem::children(), QGraphicsItem::d_ptr, QMetaObject::invokeMethod(), QGraphicsItem::isSelected(), QGraphicsItem::isVisible(), QGraphicsItem::isWidget(), QGraphicsItem::itemChange(), QGraphicsItem::parentItem(), QGraphicsItem::parentWidget(), QGraphicsItem::scene(), and selectionChanged().

Referenced by addEllipse(), addItem(), View::addItems(), addLine(), addPath(), addPixmap(), addPolygon(), addRect(), addSimpleText(), addText(), addWidget(), createItemGroup(), DiagramScene::mousePressEvent(), DiagramScene::mouseReleaseEvent(), QGraphicsItem::QGraphicsItem(), AddCommand::redo(), removeItem(), and DeleteCommand::undo().

    if (!item) {
        qWarning("QGraphicsScene::addItem: cannot add null item");
    if (item->scene() == this) {
        qWarning("QGraphicsScene::addItem: item has already been added to this scene");

    // Remove this item from its existing scene
    if (QGraphicsScene *oldScene = item->scene())

    // Notify the item that its scene is changing, and allow the item to
    // react.
    QGraphicsScene *targetScene = qVariantValue<QGraphicsScene *>(item->itemChange(QGraphicsItem::ItemSceneChange,
                                                                                   qVariantFromValue<QGraphicsScene *>(this)));
    if (targetScene != this) {
        if (targetScene && item->scene() != targetScene)

    // Prevent reusing a recently deleted pointer: purge all removed items
    // from our lists.

    // Detach this item from its parent if the parent's scene is different
    // from this scene.
    if (QGraphicsItem *itemParent = item->parentItem()) {
        if (itemParent->scene() != this) {
            QVariant variant;
            qVariantSetValue<QGraphicsItem *>(variant, item);
            itemParent->itemChange(QGraphicsItem::ItemChildRemovedChange, variant);
            item->d_func()->parent = 0;

    // Add the item to this scene
    item->d_func()->scene = targetScene;

    // Indexing requires sceneBoundingRect(), but because \a item might
    // not be completely constructed at this point, we need to store it in
    // a temporary list and schedule an indexing for later.
    d->unindexedItems << item;
    item->d_func()->index = -1;

    // Add to list of items that require an update. We cannot assume that the
    // item is fully constructed, so calling item->update() can lead to a pure
    // virtual function call to boundingRect().
    if (!d->updateAll) {
        if (d->pendingUpdateItems.isEmpty())
            QMetaObject::invokeMethod(this, "_q_updateLater", Qt::QueuedConnection);
        d->pendingUpdateItems << item;

    // Disable selectionChanged() for individual items
    int oldSelectedItemSize = d->selectedItems.size();

    // Update selection lists
    if (item->isSelected())
        d->selectedItems << item;
    if (item->isWidget() && item->isVisible() && static_cast<QGraphicsWidget *>(item)->windowType() == Qt::Popup)
        d->addPopup(static_cast<QGraphicsWidget *>(item));

    // Update creation order focus chain. Make sure to leave the widget's
    // internal tab order intact.
    if (item->isWidget()) {
        QGraphicsWidget *widget = static_cast<QGraphicsWidget *>(item);
        if (!d->tabFocusFirst) {
            // No first tab focus widget - make this the first tab focus
            // widget.
            d->tabFocusFirst = widget;
        } else if (!widget->parentWidget()) {
            // Adding a widget that is not part of a tab focus chain.
            widget->d_func()->focusNext = d->tabFocusFirst;
            widget->d_func()->focusPrev = d->tabFocusFirst->d_func()->focusPrev;
            d->tabFocusFirst->d_func()->focusPrev->d_func()->focusNext = widget;
            d->tabFocusFirst->d_func()->focusPrev = widget;

    // Add all children recursively
    foreach (QGraphicsItem *child, item->children())

    if (!item->d_ptr->explicitlyHidden) {
       if (d->unpolishedItems.isEmpty())
           QMetaObject::invokeMethod(this, "_q_polishItems", Qt::QueuedConnection);
       d->unpolishedItems << item;

    // Reenable selectionChanged() for individual items
    if (!d->selectionChanging && d->selectedItems.size() != oldSelectedItemSize)
        emit selectionChanged();

    // Deliver post-change notification
    item->itemChange(QGraphicsItem::ItemSceneHasChanged, qVariantFromValue<QGraphicsScene *>(this));

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