QQuickWindow/View: set a QObject-parent on the root item

People are often confused why eg. the objects from:

    window->contentItem()->findChildren()

are not included in window->findChildren(). This change connects
the item tree to the window's object tree to make findChild() and
findChildren() produce expected results. The same technique is
already used for QQuickFlickable's contentItem.

[ChangeLog][QtQuick][QQuickWindow] Set the window as the QObject-parent
of the contentItem to ensure consistent behavior for calling
findChildren() on QQuickWindow and QQuickWindow::contentItem.

[ChangeLog][QtQuick][QQuickView] Set the window's contentItem as the
QObject-parent of the rootObject to ensure consistent behavior for
calling findChildren() on QQuickWindow::contentItem and
QQuickView::rootObject.

Change-Id: Idb7834eb5e560088ca849e6ce90e6fa3b3ae3e91
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

1 files changed, 24 insertions, 0 deletions

diff --git a/tests/auto/quick/qquickwindow/tst_qquickwindow.cpp b/tests/auto/quick/qquickwindow/tst_qquickwindow.cpp
index 1d6547c5be..daa5e53730 100644
--- a/tests/auto/quick/qquickwindow/tst_qquickwindow.cpp
+++ b/tests/auto/quick/qquickwindow/tst_qquickwindow.cpp
@@ -375,6 +375,8 @@ private slots:
 
     void testDragEventPropertyPropagation();
 
+    void findChild();
+
 private:
     QTouchDevice *touchDevice;
     QTouchDevice *touchDeviceWithVelocity;
@@ -2831,6 +2833,28 @@ void tst_qquickwindow::testDragEventPropertyPropagation()
     }
 }
 
+void tst_qquickwindow::findChild()
+{
+    QQuickWindow window;
+
+    // QQuickWindow
+    // |_ QQuickWindow::contentItem
+    // |  |_ QObject("contentItemChild")
+    // |_ QObject("viewChild")
+
+    QObject *windowChild = new QObject(&window);
+    windowChild->setObjectName("windowChild");
+
+    QObject *contentItemChild = new QObject(window.contentItem());
+    contentItemChild->setObjectName("contentItemChild");
+
+    QCOMPARE(window.findChild<QObject *>("windowChild"), windowChild);
+    QCOMPARE(window.findChild<QObject *>("contentItemChild"), contentItemChild);
+
+    QVERIFY(!window.contentItem()->findChild<QObject *>("viewChild")); // sibling
+    QCOMPARE(window.contentItem()->findChild<QObject *>("contentItemChild"), contentItemChild);
+}
+
 QTEST_MAIN(tst_qquickwindow)
 
 #include "tst_qquickwindow.moc"