Fix moving of multiple items, and moving items backwards

To fix backward movements, all backward movements are now flipped
into forward movements (as is done in ListModel implemenation).

Movement of multiple items wasn't working as views weren't removing
the right indexes in these cases.

Task-number: QTBUG-19208
Change-Id: I9866ddabc241c066bb77329a6761d500d79aaf61
Reviewed-on: http://codereview.qt.nokia.com/2262
Reviewed-by: Bea Lam <bea.lam@nokia.com>
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>

4 files changed, 35 insertions, 18 deletions

diff --git a/src/declarative/items/qsggridview.cpp b/src/declarative/items/qsggridview.cpp
index 5531c153a3..214481a288 100644
--- a/src/declarative/items/qsggridview.cpp
+++ b/src/declarative/items/qsggridview.cpp
@@ -1497,11 +1497,13 @@ void QSGGridView::itemsMoved(int from, int to, int count)
     }
 
     d->moveReason = QSGGridViewPrivate::Other;
-    FxGridItemSG *firstVisible = static_cast<FxGridItemSG*>(d->firstVisibleItem());
-    QHash<int,FxGridItemSG*> moved;
-    int moveByCount = 0;
 
     bool movingBackwards = from > to;
+    d->adjustMoveParameters(&from, &to, &count);
+
+    QHash<int,FxGridItemSG*> moved;
+    int moveByCount = 0;
+    FxGridItemSG *firstVisible = static_cast<FxGridItemSG*>(d->firstVisibleItem());
     int firstItemIndex = firstVisible ? firstVisible->index : -1;
 
     // if visibleItems.first() is above the content start pos, and the items
@@ -1532,19 +1534,20 @@ void QSGGridView::itemsMoved(int from, int to, int count)
         }
     }
 
-    int remaining = count;
+    int movedCount = 0;
     int endIndex = d->visibleIndex;
     it = d->visibleItems.begin();
     while (it != d->visibleItems.end()) {
         FxViewItem *item = *it;
-        if (remaining && item->index >= to && item->index < to + count) {
+        if (movedCount < count && item->index >= to && item->index < to + count) {
             // place items in the target position, reusing any existing items
-            FxGridItemSG *movedItem = moved.take(item->index);
+            int targetIndex = item->index + movedCount;
+            FxGridItemSG *movedItem = moved.take(targetIndex);
             if (!movedItem)
-                movedItem = static_cast<FxGridItemSG*>(d->createItem(item->index));
+                movedItem = static_cast<FxGridItemSG*>(d->createItem(targetIndex));
             it = d->visibleItems.insert(it, movedItem);
             ++it;
-            --remaining;
+            ++movedCount;
         } else {
             if (item->index != -1) {
                 if (item->index >= to) {
diff --git a/src/declarative/items/qsgitemview.cpp b/src/declarative/items/qsgitemview.cpp
index 18015edf44..bcb4a8a97c 100644
--- a/src/declarative/items/qsgitemview.cpp
+++ b/src/declarative/items/qsgitemview.cpp
@@ -1089,6 +1089,18 @@ int QSGItemViewPrivate::mapFromModel(int modelIndex) const
     return -1; // Not in visibleList
 }
 
+void QSGItemViewPrivate::adjustMoveParameters(int *from, int *to, int *count) const
+{
+    if (*from > *to) {
+        // Only move forwards - flip if backwards moving
+        int tfrom = *from;
+        int tto = *to;
+        *from = tto;
+        *to = tto + *count;
+        *count = tfrom - tto;
+    }
+}
+
 void QSGItemViewPrivate::init()
 {
     Q_Q(QSGItemView);
diff --git a/src/declarative/items/qsgitemview_p_p.h b/src/declarative/items/qsgitemview_p_p.h
index bc2e45ff88..3113a8b754 100644
--- a/src/declarative/items/qsgitemview_p_p.h
+++ b/src/declarative/items/qsgitemview_p_p.h
@@ -92,6 +92,7 @@ public:
     FxViewItem *visibleItem(int modelIndex) const;
     FxViewItem *firstVisibleItem() const;
     int mapFromModel(int modelIndex) const;
+    void adjustMoveParameters(int *from, int *to, int *count) const;
 
     virtual void init();
     virtual void updateCurrent(int modelIndex);
diff --git a/src/declarative/items/qsglistview.cpp b/src/declarative/items/qsglistview.cpp
index 7fbfe3c68d..37b027cd36 100644
--- a/src/declarative/items/qsglistview.cpp
+++ b/src/declarative/items/qsglistview.cpp
@@ -1813,11 +1813,13 @@ void QSGListView::itemsMoved(int from, int to, int count)
     }
 
     d->moveReason = QSGListViewPrivate::Other;
-    FxViewItem *firstVisible = d->firstVisibleItem();
-    QHash<int,FxViewItem*> moved;
-    int moveBy = 0;
 
     bool movingBackwards = from > to;
+    d->adjustMoveParameters(&from, &to, &count);
+
+    QHash<int,FxViewItem*> moved;
+    int moveBy = 0;
+    FxViewItem *firstVisible = d->firstVisibleItem();
     int firstItemIndex = firstVisible ? firstVisible->index : -1;
 
     // if visibleItems.first() is above the content start pos, and the items
@@ -1845,21 +1847,20 @@ void QSGListView::itemsMoved(int from, int to, int count)
         }
     }
 
-    int remaining = count;
+    int movedCount = 0;
     int endIndex = d->visibleIndex;
     it = d->visibleItems.begin();
     while (it != d->visibleItems.end()) {
         FxViewItem *item = *it;
-        if (remaining && item->index >= to && item->index < to + count) {
+        if (movedCount < count && item->index >= to && item->index < to + count) {
             // place items in the target position, reusing any existing items
-            FxViewItem *movedItem = moved.take(item->index);
+            int targetIndex = item->index + movedCount;
+            FxViewItem *movedItem = moved.take(targetIndex);
             if (!movedItem)
-                movedItem = d->createItem(item->index);
-            if (item->index <= firstVisible->index)
-                moveBy -= movedItem->size();
+                movedItem = d->createItem(targetIndex);
             it = d->visibleItems.insert(it, movedItem);
             ++it;
-            --remaining;
+            ++movedCount;
         } else {
             if (item->index != -1) {
                 if (item->index >= to) {