Re: Gtk::TreeView

[Bob Caryl <bob fis-cal com>]

Rose Cumming wrote:

> Hello,
>
> I'm new to using Gtk::TreeView.
> I have a tree view with 2 columns. One column for texts and one column 
> for a boolean.
>
> If I want to perform some functions when the "check box" (for the 
> boolean value) is checked/unchecked on a certain row, which signal do 
> I use to connect my signal handler?
>
> And if this row has some children rows, is there a way I can find and 
> iterate through these children rows under the currently selected row?
>
> I cannot find any examples around.
>
> Any suggestion will be appreciated.
>
> Thanks,
> Rose
>
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Hi Rose,

I use the checkbox as a column.  Here's how I do it:
   // create the check box column
   tree->append_column_editable("Access", m_columns.m_check);
   // connect to the cell renderer's "signal_toggled" signal  
   ((Gtk::CellRendererToggle 
*)tree->get_column_cell_renderer(0))->signal_toggled().connect(sigc::mem_fun(*this, 
&Menucfg::on_child_toggled));

As for iterating through the tree, whenever a row check box is toggled, 
I want to do just that, except that I want all descendents *and* 
ancestors of that row to be checked as well, so here is how I do that:

There are two functions involved:

// this handles both cases, the button was checked, or unchecked.  First 
it calls
// check_all_children to handle descendants, then it goes on to handle 
ancestors
void Menucfg::on_child_toggled(Glib::ustring str)
{
  
   Gtk::TreeModel::Path path(str.c_str());
   Gtk::TreeModel::Row row = *(list->get_iter(path));
   Gtk::TreeModel::Row parent = *(row.parent());
   Gtk::TreeModel::Children::iterator iter;
   Gtk::TreeModel::Children children = row.children();
  
   if(children)
       check_all_children(children,row[m_columns.m_check]);
  
   if(row[m_columns.m_check])
   {
       while(parent)
       {
           parent[m_columns.m_check] = true;
           parent = *(parent.parent());
       }
   }
   else
   {
       while(parent)
       {
           Gtk::TreeModel::Children siblings = parent.children();
           for(iter = siblings.begin(); iter != siblings.end(); ++iter)
           {
               Gtk::TreeModel::Row child_row = *iter;
               if(child_row[m_columns.m_check])
                   break;
           }
           parent[m_columns.m_check] = (iter != siblings.end());
           parent = *(parent.parent());
       }
   }
}

// check_all_children toggles the checked state of all descendants
// of the current row if there are any.  If it encounters a row that
// also has descendants, it just recursively calls itself.
void Menucfg::check_all_children(Gtk::TreeModel::Children& children,bool 
condition)
{
   for(Gtk::TreeModel::Children::iterator iter = children.begin(); iter 
!= children.end(); ++iter)
   {
       Gtk::TreeModel::Row child_row = *iter;
       child_row[m_columns.m_check] = condition;
       Gtk::TreeModel::Children next = child_row.children();
       if(next)
           check_all_children(next,condition);
   }       
}


I hope this helps. 

Bob Caryl

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title:Senior Software Design Engineer
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