How to know the QTreeView item decoration is clicked - c++

Question

I'm trying to know when the user selects the decoration of an item, because I was trying to implement a single click expand/collapse QTreeview and the decoration now does nothing. It doesn't expand or collapse the item where as if I click on the item it works properly.
void MyTreeView::mousePressEvent(QMouseEvent *event)
{
QTreeView::mousePressEvent(event);
if (event->button() == Qt::LeftButton)
{
QModelIndex index = indexAt(event->pos());
isExpanded(index) ? collapse(index) : expand(index);
}
}
The problem is that when the decoration is selected, it enters the if condition. If it was not, everything works fine.
I don't know if I have to block the decoration action or have a condition in the if statement.
How do I know the decoration is selected and not the item itself or how do I block decoration action ?

Answer 1

Try this:
void MyTreeView::mousePressEvent( QMouseEvent* aEvent )
{
QModelIndex index = indexAt( aEvent->pos() );
if ( index.isValid() )
{
const bool wasExpanded = isExpanded( index );
QTreeView::mousePressEvent( aEvent );
if ( aEvent->button() == Qt::LeftButton )
{
const bool expanded = isExpanded( index );
// QTreeView did not change the item's state ... but you want.
if ( wasExpanded == expanded )
{
expanded ? collapse( index ) : expand( index );
}
}
}
else
{
QTreeView::mousePressEvent( aEvent );
}
}