ListView with StrictlyEnforceRange skips over items

When list item size varies smaller items next to larger
items may not be able to become the current item.  Ensure
the snap item is found using the correct range, i.e.
half of previous item above snap pos and half of next item
below.

Change-Id: I52ae235e6b801bda48fcb636bb4150ab643715e8
Fixes: QTBUG-20745
Reviewed-on: http://codereview.qt.nokia.com/2650
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Bea Lam <bea.lam@nokia.com>

diff --git a/src/declarative/items/qsglistview.cpp b/src/declarative/items/qsglistview.cpp
index e162339..c8e8817 100644 (file)
--- a/src/declarative/items/qsglistview.cpp
+++ b/src/declarative/items/qsglistview.cpp
@@ -434,6 +434,7 @@ qreal QSGListViewPrivate::snapPosAt(qreal pos)
 FxViewItem *QSGListViewPrivate::snapItemAt(qreal pos)
 {
     FxViewItem *snapItem = 0;
+    qreal prevItemSize = 0;
     for (int i = 0; i < visibleItems.count(); ++i) {
         FxViewItem *item = visibleItems.at(i);
         if (item->index == -1)
@@ -441,8 +442,9 @@ FxViewItem *QSGListViewPrivate::snapItemAt(qreal pos)
         qreal itemTop = item->position();
         if (highlight && itemTop >= pos && item->endPosition() <= pos + highlight->size())
             return item;
-        if (itemTop+item->size()/2 >= pos && itemTop-item->size()/2 < pos)
+        if (itemTop+item->size()/2 >= pos && itemTop-prevItemSize/2 < pos)
             snapItem = item;
+        prevItemSize = item->size();
     }
     return snapItem;
 }

diff --git a/src/qtquick1/graphicsitems/qdeclarativelistview.cpp b/src/qtquick1/graphicsitems/qdeclarativelistview.cpp
index 244a2b8..bc06f9b 100644 (file)
--- a/src/qtquick1/graphicsitems/qdeclarativelistview.cpp
+++ b/src/qtquick1/graphicsitems/qdeclarativelistview.cpp
@@ -446,6 +446,7 @@ public:
 
     FxListItem1 *snapItemAt(qreal pos) {
         FxListItem1 *snapItem = 0;
+        qreal prevItemSize = 0;
         for (int i = 0; i < visibleItems.count(); ++i) {
             FxListItem1 *item = visibleItems[i];
             if (item->index == -1)
@@ -453,8 +454,9 @@ public:
             qreal itemTop = item->position();
             if (highlight && itemTop >= pos && item->endPosition() <= pos + highlight->size() - 1)
                 return item;
-            if (itemTop+item->size()/2 >= pos && itemTop-item->size()/2 < pos)
+            if (itemTop+item->size()/2 >= pos && itemTop-prevItemSize/2 < pos)
                 snapItem = item;
+            prevItemSize = item->size();
         }
         return snapItem;
     }