QueryDataModel

This function transfers ownership for QObject objects, if the returned object doesn't have any parent.

The ListView will pass the data item as a parameter to ListItemProvider::updateItem(). If item visuals are created by using ListItemComponent in QML, ListView makes the data returned from this function available in the item visuals as the context property ListItemData, and also as the property ListItem.data attached to the item visual root node.

ListView never calls this function for its root node (but does call childCount(QVariantList) for the root node), so if this DataModel only contains one level of items (no child items), this function can always return false.

Here's an example of how to override hasChildren().

 bool SmartViewModel::hasChildren(const QVariantList &indexPath)
 {
     // Checks whether the indexPath is an empty array.
     // An empty array indicates the the index path is for the
     // root element.
     if(indexPath.empty())
         return true; // The root node always has children

     // ...Check for other index paths...
 }

The item type will then be used when the ListView requests items from its ListItemProvider. It will also be used when the DataModel has indicated that items have been updated using the signals DataModel::itemUpdated or DataModel::itemsChanged with DataModelChangeType::Update.

If a ListItemTypeMapper has been provided to a ListView, the ListView calls ListItemTypeMapper::itemType() instead of DataModel::itemType().