Fix QAbstractItemModel::beginRemoveRows in examples

QAbstractItemModel::beginRemoveRows() must not take a negative value
for first or last. It will assert so we should make sure the examples
are correct.
The assertion was added in 00c09e752ff7e482e1308e0e34721dc979204595

Change-Id: I539175c0597ed6f0ae76b7493fd3dca40638714e
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Reviewed-by: Martin Smith <martin.smith@qt.io>

2 files changed, 9 insertions, 4 deletions

diff --git a/examples/widgets/itemviews/fetchmore/filelistmodel.cpp b/examples/widgets/itemviews/fetchmore/filelistmodel.cpp
index cd21712e04..086d45eca3 100644
--- a/examples/widgets/itemviews/fetchmore/filelistmodel.cpp
+++ b/examples/widgets/itemviews/fetchmore/filelistmodel.cpp
@@ -103,6 +103,9 @@ void FileListModel::fetchMore(const QModelIndex & /* index */)
     int remainder = fileList.size() - fileCount;
     int itemsToFetch = qMin(100, remainder);
 
+    if (itemsToFetch <= 0)
+        return;
+
     beginInsertRows(QModelIndex(), fileCount, fileCount+itemsToFetch-1);
 
     fileCount += itemsToFetch;
diff --git a/examples/widgets/itemviews/puzzle/piecesmodel.cpp b/examples/widgets/itemviews/puzzle/piecesmodel.cpp
index f0649d3776..28b46836f4 100644
--- a/examples/widgets/itemviews/puzzle/piecesmodel.cpp
+++ b/examples/widgets/itemviews/puzzle/piecesmodel.cpp
@@ -203,10 +203,12 @@ Qt::DropActions PiecesModel::supportedDropActions() const
 
 void PiecesModel::addPieces(const QPixmap& pixmap)
 {
-    beginRemoveRows(QModelIndex(), 0, 24);
-    pixmaps.clear();
-    locations.clear();
-    endRemoveRows();
+    if (!pixmaps.isEmpty()) {
+        beginRemoveRows(QModelIndex(), 0, pixmaps.size() - 1);
+        pixmaps.clear();
+        locations.clear();
+        endRemoveRows();
+    }
     for (int y = 0; y < 5; ++y) {
         for (int x = 0; x < 5; ++x) {
             QPixmap pieceImage = pixmap.copy(x*m_PieceSize, y*m_PieceSize, m_PieceSize, m_PieceSize);