Fix ListView.isCurrentItem when used with DelegateModel

Fixes: QTBUG-86744
Pick-to: 5.15 6.1 6.2
Change-Id: I7287b39afc8f84e336aa46739b534e33e4212ea7
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

src/quick/items/qquickitemview.cpp

@@ -2402,6 +2402,8 @@ void QQuickItemView::createdItem(int index, QObject* object)
             d->repositionPackageItemAt(item, index);
         else if (index == d->currentIndex)
             d->updateCurrent(index);
+    } else if (index == d->currentIndex) {
+        d->updateCurrent(index);
     }
 }
 

tests/auto/quick/qquicklistview/data/qtbug86744.qml

@@ -0,0 +1,21 @@
+import QtQuick 2.15
+import QtQml.Models 2.15
+
+Item {
+    height: 200
+    width: 100
+    DelegateModel {
+        id: dm
+        model: 2
+        delegate: Item {
+            width: 100; height: 20
+            property bool isCurrent: ListView.isCurrentItem
+        }
+    }
+    ListView {
+        objectName: "listView"
+        model: dm
+        currentIndex: 1
+        anchors.fill: parent
+    }
+}

tests/auto/quick/qquicklistview/tst_qquicklistview.cpp

@@ -303,6 +303,7 @@ private slots:
     void requiredObjectListModel();
     void clickHeaderAndFooterWhenClip();
     void animatedDelegate();
+    void isCurrentItem_DelegateModel();
 
     // WARNING: please add new tests to tst_qquicklistview2; this file is too slow to work with.
 
@@ -10124,6 +10125,20 @@ void tst_QQuickListView::animatedDelegate()
     }
 }
 
+void tst_QQuickListView::isCurrentItem_DelegateModel()
+{
+    QScopedPointer<QQuickView> window(createView());
+    window->setSource(testFileUrl("qtbug86744.qml"));
+    window->resize(640, 480);
+    window->show();
+    QVERIFY(QTest::qWaitForWindowExposed(window.data()));
+
+    QQuickListView* listView = window->rootObject()->findChild<QQuickListView*>("listView");
+    QVERIFY(listView);
+    QVariant value = listView->itemAtIndex(1)->property("isCurrent");
+    QVERIFY(value.toBool() == true);
+}
+
 // WARNING: please add new tests to tst_qquicklistview2; this file is too slow to work with.
 
 QTEST_MAIN(tst_QQuickListView)