Is there any way to get a list of currently visible items in QAbstractItemView
? And, if it possible, to receive any notifications about changing of this list.
Upd:
I'm asking exactly about QAbstractItemView
or QTreeView
with non-plain structure, not QTableView
.
Upd2: I'm implementing tree view model with checkboxes. I want next behavior (same for checking/uncheking):
Check state are monitored/modified by external data source, so I need a mechanism to update all changed children/parents. dataChanged
signal is not enough for me because it is very expansive to build a list of all changed QModelIndex
for updating. And it is not necessary at all, because all fresh data will be picked from QAbstractItemModel::data
.
I found next dirty hack to update all items: emit dataChanged( QModelIndex(), QModelIndex() );
but it's undocumented for invalid indexes.
So, I need a way to force all visible items redraw they content with fresh data.
I think that there are no cases where list of visible items is required. In case of correct model implementation, all items are updated automatically.
Hard part of implementation — force children and parents to update. I wrote the following code:
bool TreeModel::setData( const QModelIndex &index, const QVariant &value, int role )
case Qt::CheckStateRole:
{
TreeItemList updateRangeList; // Filled with items, in which all childred must be updated
TreeItemList updateSingleList; // Filled with items, which must be updated
item->setCheckState( value.toBool(), updateRangeList, updateSingleList ); // All magic there
foreach ( TreeAbstractItem *i, updateRangeList )
{
const int nRows = i->rowCount();
QModelIndex topLeft = indexForItem( i->m_childs[0] );
QModelIndex bottomRight = indexForItem( i->m_childs[nRows - 1] );
emit dataChanged( topLeft, bottomRight );
}
foreach ( TreeAbstractItem *i, updateSingleList )
{
QModelIndex updateIndex = indexForItem( i );
emit dataChanged( updateIndex, updateIndex );
}
}