QPersistentModelIndex problem

[laugusti]

Hi all,

Here is my problem ... I have a widget containing 4 tree views connected to the same model. I store QModelIndex to be able to restore expanded items when I switch from a tree view to another.
In order to do it, I want to use QPersistentModelIndex because if I delete a QModelIndex from my model, the QPersistentModelIndex would become invalid. At least, it's what I understood from the documentation.

Here is my code:


/**
* List of expanded items.
*/
QModelIndexList m_expandedItemList;

//================================================== ==============
void QResourceTree::addExpandedItem(const QModelIndex& index)
{
QResourceProxyModel * proxyModel = (QResourceProxyModel*)model();
QModelIndex sourceIndex = proxyModel->mapToSource(index);
m_expandedItemList.append(QPersistentModelIndex(so urceIndex));
}

//================================================== ==============
void QResourceTree::restoreExpandedItems() {

if (!m_expandedItemList.empty()) {

/* Restore expanded items */
QModelIndexList::iterator it;
for (it=m_expandedItemList.begin() ; it != m_expandedItemList.end(); it++) {

if ((*it).isValid()) {

QResourceProxyModel * proxyModel = (QResourceProxyModel*)model();
QModelIndex index = proxyModel->mapFromSource(*it);

if (index.isValid() && !isExpanded(index)) {
this->expand(index);
}
}
}
}
}

Code for deletion:


// Is it the right order?
1/ m_root->removeChildren(index.row());
2/ changePersistentIndex(index, QModelIndex());

Anytime I delete an expanded item, when I restore the expanded item list, it crashes because my QPersistentModelIndex is still valid.
How do we get a persistent index from a model index? I thought it would be by using the constructor, maybe I am wrong?
Anybody has an example showing how to use QPersistentModelIndex?


Thanks,
Lionel

[caduel]

you must not store the perstistent model indexes in a QModelIndexList; use
QList<QPersistentModelIndex> instead

HTH

[laugusti]

Thank you Caduel,

It works perfectly now!

Regards,
Lionel