Don't ignore model changes when the ListView scroll position changes.

If there are pending changes when the ListView viewport changes then
do a full layout instead of a refill.  Likewise for GridView and when
animations finish or the cacheBuffer size changes.

Change-Id: I57a2b01fee5729381558af366dad24ba26c223ef
Reviewed-by: Bea Lam <bea.lam@nokia.com>

4 files changed, 18 insertions, 5 deletions

diff --git a/src/quick/items/qquickgridview.cpp b/src/quick/items/qquickgridview.cpp
index 1fab4a8c99..0caf93c98b 100644
--- a/src/quick/items/qquickgridview.cpp
+++ b/src/quick/items/qquickgridview.cpp
@@ -1884,7 +1884,7 @@ void QQuickGridView::viewportMoved()
     else
         d->bufferMode = d->hData.smoothVelocity < 0 ? QQuickItemViewPrivate::BufferBefore : QQuickItemViewPrivate::BufferAfter;
 
-    d->refill();
+    d->refillOrLayout();
 
     // Set visibility of items to eliminate cost of items outside the visible area.
     qreal from = d->isContentFlowReversed() ? -d->position()-d->size() : d->position();
diff --git a/src/quick/items/qquickitemview.cpp b/src/quick/items/qquickitemview.cpp
index 209d30aa74..64c05aab92 100644
--- a/src/quick/items/qquickitemview.cpp
+++ b/src/quick/items/qquickitemview.cpp
@@ -442,7 +442,7 @@ void QQuickItemView::setCacheBuffer(int b)
         d->buffer = b;
         if (isComponentComplete()) {
             d->bufferMode = QQuickItemViewPrivate::BufferBefore | QQuickItemViewPrivate::BufferAfter;
-            d->refill();
+            d->refillOrLayout();
         }
         emit cacheBufferChanged();
     }
@@ -1075,7 +1075,7 @@ void QQuickItemView::animStopped()
 {
     Q_D(QQuickItemView);
     d->bufferMode = QQuickItemViewPrivate::BufferBefore | QQuickItemViewPrivate::BufferAfter;
-    d->refill();
+    d->refillOrLayout();
     if (d->haveHighlightRange && d->highlightRange == QQuickItemView::StrictlyEnforceRange)
         d->updateHighlight();
 }
@@ -1777,7 +1777,7 @@ void QQuickItemViewPrivate::layout()
 bool QQuickItemViewPrivate::applyModelChanges(ChangeResult *totalInsertionResult, ChangeResult *totalRemovalResult)
 {
     Q_Q(QQuickItemView);
-    if (!q->isComponentComplete() || (!currentChanges.hasPendingChanges() && !bufferedChanges.hasPendingChanges() && !runDelayedRemoveTransition) || disableLayout)
+    if (!q->isComponentComplete() || !hasPendingChanges() || disableLayout)
         return false;
 
     disableLayout = true;
diff --git a/src/quick/items/qquickitemview_p_p.h b/src/quick/items/qquickitemview_p_p.h
index e352c461d6..1e29faf10f 100644
--- a/src/quick/items/qquickitemview_p_p.h
+++ b/src/quick/items/qquickitemview_p_p.h
@@ -229,6 +229,19 @@ public:
             hData.markExtentsDirty();
     }
 
+    bool hasPendingChanges() const {
+        return currentChanges.hasPendingChanges()
+                || bufferedChanges.hasPendingChanges()
+                ||runDelayedRemoveTransition;
+    }
+
+    void refillOrLayout() {
+        if (hasPendingChanges())
+            layout();
+        else
+            refill();
+    }
+
     QQmlGuard<QQuickVisualModel> model;
     QVariant modelVariant;
     int itemCount;
diff --git a/src/quick/items/qquicklistview.cpp b/src/quick/items/qquicklistview.cpp
index 1cc2637fe6..b65cb85465 100644
--- a/src/quick/items/qquicklistview.cpp
+++ b/src/quick/items/qquicklistview.cpp
@@ -2557,7 +2557,7 @@ void QQuickListView::viewportMoved()
     else
         d->bufferMode = d->hData.smoothVelocity < 0 ? QQuickListViewPrivate::BufferBefore : QQuickListViewPrivate::BufferAfter;
 
-    d->refill();
+    d->refillOrLayout();
 
     // Set visibility of items to eliminate cost of items outside the visible area.
     qreal from = d->isContentFlowReversed() ? -d->position()-d->size() : d->position();