itemviews: When an index widget gets focus, update the current index

By ensuring that the current index follows the focus of an index widget,
we can ensure that moving the cursor will happen in the way that is
expected from the focused widget.

Task-number: QTBUG-27793
Change-Id: Ia36891a94ce41c7d12fba678de23a6f3b69374ae
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
Reviewed-by: Christian Ehrlicher <ch.ehrlicher@gmx.de>

src/widgets/itemviews/qabstractitemview.cpp

@@ -3217,12 +3217,14 @@ void QAbstractItemView::setIndexWidget(const QModelIndex &index, QWidget *widget
     if (QWidget *oldWidget = indexWidget(index)) {
         d->persistent.remove(oldWidget);
         d->removeEditor(oldWidget);
+        oldWidget->removeEventFilter(this);
         oldWidget->deleteLater();
     }
     if (widget) {
         widget->setParent(viewport());
         d->persistent.insert(widget);
         d->addEditor(index, widget, true);
+        widget->installEventFilter(this);
         widget->show();
         dataChanged(index, index); // update the geometry
         if (!d->delayedPendingLayout)
@@ -4499,6 +4501,24 @@ QModelIndexList QAbstractItemViewPrivate::selectedDraggableIndexes() const
     return indexes;
 }
 
+/*!
+    \reimp
+*/
+
+bool QAbstractItemView::eventFilter(QObject *object, QEvent *event)
+{
+    Q_D(QAbstractItemView);
+    if (object == this || object == viewport() || event->type() != QEvent::FocusIn)
+        return QAbstractScrollArea::eventFilter(object, event);
+    QWidget *widget = qobject_cast<QWidget *>(object);
+    // If it is not a persistent widget then we did not install
+    // the event filter on it, so assume a base implementation is
+    // filtering
+    if (!widget || !d->persistent.contains(widget))
+        return QAbstractScrollArea::eventFilter(object, event);
+    setCurrentIndex(d->indexForEditor(widget));
+    return false;
+}
 
 QT_END_NAMESPACE
 

src/widgets/itemviews/qabstractitemview.h

@@ -346,6 +346,7 @@ protected:
     void resizeEvent(QResizeEvent *event) override;
     void timerEvent(QTimerEvent *event) override;
     void inputMethodEvent(QInputMethodEvent *event) override;
+    bool eventFilter(QObject *object, QEvent *event) override;
 
 #ifndef QT_NO_DRAGANDDROP
     enum DropIndicatorPosition { OnItem, AboveItem, BelowItem, OnViewport };

tests/auto/widgets/itemviews/qabstractitemview/tst_qabstractitemview.cpp

@@ -147,6 +147,8 @@ private slots:
     void testClearModelInClickedSignal();
     void inputMethodEnabled_data();
     void inputMethodEnabled();
+    void currentFollowsIndexWidget_data();
+    void currentFollowsIndexWidget();
 };
 
 class MyAbstractItemDelegate : public QAbstractItemDelegate
@@ -2390,5 +2392,56 @@ void tst_QAbstractItemView::inputMethodEnabled()
     QCOMPARE(view->testAttribute(Qt::WA_InputMethodEnabled), result);
 }
 
+void tst_QAbstractItemView::currentFollowsIndexWidget_data()
+{
+    QTest::addColumn<QByteArray>("viewType");
+
+    QList<QByteArray> widgets;
+    widgets << "QListView" << "QTreeView" << "QTableView";
+    for (const QByteArray &widget : qAsConst(widgets))
+        QTest::newRow(widget) << widget;
+}
+
+void tst_QAbstractItemView::currentFollowsIndexWidget()
+{
+    QFETCH(QByteArray, viewType);
+
+    QScopedPointer<QAbstractItemView> view;
+    if (viewType == "QListView")
+        view.reset(new QListView());
+    else if (viewType == "QTableView")
+        view.reset(new QTableView());
+    else if (viewType == "QTreeView")
+        view.reset(new QTreeView());
+    else
+        QVERIFY(0);
+
+    centerOnScreen(view.data());
+    view->show();
+    QVERIFY(QTest::qWaitForWindowExposed(view.data()));
+
+    QStandardItemModel *model = new QStandardItemModel(view.data());
+    QStandardItem *item1 = new QStandardItem("first item");
+    item1->setFlags(Qt::ItemIsSelectable | Qt::ItemIsEnabled);
+    model->appendRow(item1);
+
+    QStandardItem *item2 = new QStandardItem("test item");
+    item2->setFlags(Qt::ItemIsSelectable | Qt::ItemIsEnabled);
+    model->appendRow(item2);
+
+    view->setModel(model);
+    QLineEdit *lineEdit1 = new QLineEdit;
+    QLineEdit *lineEdit2 = new QLineEdit;
+    view->setIndexWidget(item1->index(), lineEdit1);
+    view->setIndexWidget(item2->index(), lineEdit2);
+
+    lineEdit2->setFocus();
+    QTRY_VERIFY(lineEdit2->hasFocus());
+    QCOMPARE(view->currentIndex(), item2->index());
+    lineEdit1->setFocus();
+    QTRY_VERIFY(lineEdit1->hasFocus());
+    QCOMPARE(view->currentIndex(), item1->index());
+}
+
 QTEST_MAIN(tst_QAbstractItemView)
 #include "tst_qabstractitemview.moc"