QSortFilterProxyModel崩溃的应用程序

Question

I have a model subclassed from QAbstractListModel which has a QList to maintain the data which contains QDateTime which is used to maintain this list. I have to maintain this data for an hour ie, older data will be removed from the list. This basically is FIFO list. I have a proxy model (subclass of QSortFilterProxyModel ) to sort the data. Whenever the data changes, proxy model is loosing the index and displaying data unfiltered. Following is the code snippet to do this.

emit layoutAboutToBeChanged();
beginInsertRows(QModelIndex(), 0, 1); //we are prepending
m_entries.prepend(e);
endInsertRows();
emit layoutChanged();

This seems to have solved the problem. But, if something is selected on the view ( QTreeView ), then the application is crashing after sometime with lot of these error messages.

QSortFilterProxyModel: index from wrong model passed to mapFromSource 
QSortFilterProxyModel: index from wrong model passed to mapFromSource 
QSortFilterProxyModel: index from wrong model passed to mapFromSource

Stack trace on the debugger shows the mouseSelectEvent and other functions which needs QModelIndex .

Sorry for the long question. Could someone please help in solving this problem?

Thanks.

Answer 1

The documentation of beginInsertRows says void QAbstractItemModel::beginInsertRows(const QModelIndex & parent, int first, int last) which means that when you insert only one item parameters first = last = 0. In your snippet you insert one item with m_entries.prepend(e) but you delcare that you are going to insert two: beginInsertRows(QModelIndex(), 0, 1); The view receives signal that two rows have been inserted and when it asks for the second one - boom! access violation. What you need is beginInsertRows(QModelIndex(), 0, 0); . Also I don't think you need to emit layoutAboutToBeChanged() an emit layoutChanged(); but I am not sure about that.