Reset the 'connectedToScene' flag when changing the scene of a view

In QGraphicsScene::_q_emitUpdated() the slot
QGrpahicsView::updateScene(QList<QRectF>) gets connected and a boolean
(connectedToScene) is set to prevent double connections. The problem is
that this boolean was not reset when the view gets a new scene.

Task-number: 253415
Reviewed-by: andreas

2 files changed, 25 insertions, 0 deletions

diff --git a/src/gui/graphicsview/qgraphicsview.cpp b/src/gui/graphicsview/qgraphicsview.cpp
index 05e4907..8b133f3 100644
--- a/src/gui/graphicsview/qgraphicsview.cpp
+++ b/src/gui/graphicsview/qgraphicsview.cpp
@@ -1681,6 +1681,7 @@ void QGraphicsView::setScene(QGraphicsScene *scene)
         disconnect(d->scene, SIGNAL(sceneRectChanged(QRectF)),
                    this, SLOT(updateSceneRect(QRectF)));
         d->scene->d_func()->views.removeAll(this);
+        d->connectedToScene = false;
     }
 
     // Assign the new scene and update the contents (scrollbars, etc.)).
diff --git a/tests/auto/qgraphicsview/tst_qgraphicsview.cpp b/tests/auto/qgraphicsview/tst_qgraphicsview.cpp
index b5af115..db1e4c3 100644
--- a/tests/auto/qgraphicsview/tst_qgraphicsview.cpp
+++ b/tests/auto/qgraphicsview/tst_qgraphicsview.cpp
@@ -200,6 +200,7 @@ private slots:
     void task239729_noViewUpdate();
     void task239047_fitInViewSmallViewport();
     void task245469_itemsAtPointWithClip();
+    void task253415_reconnectUpdateSceneOnSceneChanged();
 };
 
 void tst_QGraphicsView::initTestCase()
@@ -3044,5 +3045,28 @@ void tst_QGraphicsView::centerOnDirtyItem()
     QCOMPARE(before, after);
 }
 
+void tst_QGraphicsView::task253415_reconnectUpdateSceneOnSceneChanged()
+{
+    QGraphicsView view;
+    QGraphicsView dummyView;
+    view.setWindowFlags(view.windowFlags() | Qt::WindowStaysOnTopHint);
+    view.resize(200, 200);
+
+    QGraphicsScene scene1;
+    QObject::connect(&scene1, SIGNAL(changed(QList<QRectF>)), &dummyView, SLOT(updateScene(QList<QRectF>)));
+    view.setScene(&scene1);
+
+    QTest::qWait(125);
+
+    QGraphicsScene scene2;
+    QObject::connect(&scene2, SIGNAL(changed(QList<QRectF>)), &dummyView, SLOT(updateScene(QList<QRectF>)));
+    view.setScene(&scene2);
+
+    QTest::qWait(125);
+
+    bool wasConnected2 = QObject::disconnect(&scene2, SIGNAL(changed(QList<QRectF>)), &view, 0);
+    QVERIFY(wasConnected2);
+}
+
 QTEST_MAIN(tst_QGraphicsView)
 #include "tst_qgraphicsview.moc"