QTreeView disable selection on some rows

Question

I Have a JSON model, and I populate it with QTreeView:

*-group1
| |  
| *-item1     value1
| |
| *-item2     value2
|
*-group2
  |
  *-item4     value3

Now I want to disable selection for groups, so that user can select only rows with items. And I want to achive it without modification of model.

Answer 1

Use a proxy model such as QIdentityProxyModel and reimplement QAbstractItemModel::flags(), removing the Qt::ItemIsSelectable flag for the group items:

Qt::ItemFlags DisableGroupProxyModel::flags(const QModelIndex& index) const {
   const auto flags = QIdentityProxyModel::flags(index);
   if (index is group) {
       return flags & ~Qt::ItemIsSelectable;
   }

   return flags;
}

Then set the original (unmodified) model as source model of this proxy model and the proxy model instance as the tree view’s model:

DisableGroupProxyModel* proxy = new DisableGroupProxyModel(this);
proxy->setSourceModel(originalModel);
treeView->setModel(proxy);

Answer 2

This can be done with QItemSelectionModel. You can get selection model with

treeView->selectionModel();

Then connect to model's signal

void currentRowChanged(const QModelIndex &current, const QModelIndex &previous)

and inside the connected slot check if new index is group or not and if group just select previous model index.