Prevent ListView from jumping horizontally with flick(0,<number>)

The internal flick functions were not written to handle empty flicks
in invalid directions. Guard our calls accordingly.

Change-Id: I34801a7e548160ce4895dd8a2f6c0b17172cd02e
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

2 files changed, 37 insertions, 0 deletions

diff --git a/tests/auto/quick/qquicklistview/data/snapOneItemWrongDirection.qml b/tests/auto/quick/qquicklistview/data/snapOneItemWrongDirection.qml
new file mode 100644
index 0000000000..f5b7b35d0c
--- /dev/null
+++ b/tests/auto/quick/qquicklistview/data/snapOneItemWrongDirection.qml
@@ -0,0 +1,18 @@
+import QtQuick 2.0
+
+ListView {
+    width: 400
+    height: 400
+    focus: true
+
+    model: 10
+    delegate: Rectangle {
+        width: parent.width
+        height: 50
+        color: index % 2 ? "blue" : "green"
+    }
+
+    snapMode: ListView.SnapOneItem
+    Keys.onUpPressed: flick(0,500)
+    Keys.onDownPressed: flick(0,-500)
+}
diff --git a/tests/auto/quick/qquicklistview/tst_qquicklistview.cpp b/tests/auto/quick/qquicklistview/tst_qquicklistview.cpp
index 64a186eade..9c11957894 100644
--- a/tests/auto/quick/qquicklistview/tst_qquicklistview.cpp
+++ b/tests/auto/quick/qquicklistview/tst_qquicklistview.cpp
@@ -182,6 +182,7 @@ private slots:
     void snapOneItem_data();
     void snapOneItem();
     void snapOneItemCurrentIndexRemoveAnimation();
+    void snapOneItemWrongDirection();
 
     void QTBUG_9791();
     void QTBUG_33568();
@@ -5672,6 +5673,24 @@ void tst_QQuickListView::snapOneItemCurrentIndexRemoveAnimation()
     QCOMPARE(currentIndexSpy.count(), 0);
 }
 
+void tst_QQuickListView::snapOneItemWrongDirection()
+{
+    QScopedPointer<QQuickView> window(createView());
+    window->setSource(testFileUrl("snapOneItemWrongDirection.qml"));
+    window->show();
+    QVERIFY(QTest::qWaitForWindowExposed(window.data()));
+
+    QQuickListView *listview = qobject_cast<QQuickListView*>(window->rootObject());
+    QTRY_VERIFY(listview != nullptr);
+
+    QTRY_COMPARE(QQuickItemPrivate::get(listview)->polishScheduled, false);
+    QTRY_COMPARE(listview->currentIndex(), 0);
+
+    listview->flick(0,500);
+    QTRY_VERIFY(!listview->isMovingHorizontally());
+    QCOMPARE(listview->contentX(), qreal(0));
+}
+
 void tst_QQuickListView::attachedProperties_QTBUG_32836()
 {
     QScopedPointer<QQuickView> window(createView());