[pygtk] Rendering arbitrary widgets in a CellRenderer

[Walter Leibbrandt]

Hi,

I took another swing at creating a custom cell renderer that can render 
any arbitrary widget in a TreeView. It currently works, albeit with a 
few annoyances. The source is available at 
https://translate.svn.sourceforge.net/svnroot/translate/src/trunk/virtaal/virtaal/views/widgets/cellrendererwidget.py

The widget (retrieved from the TreeView's model) is rendered by wrapping 
it in a gtk.CellEditable, which was the only way I could find to render 
arbitrary widgets. This means that the cell renderer must use the 
editable mode and that the activatable mode is of no use. So the cell is 
currently rendered in one of three states:
* Unselected: A CellRendererText is emulatedwith the strfunc callable 
supplying the string to render.
* Selected (not editing): When selecting a row (with the mouse or 
keyboard) the cell is empty. Neither the string or the widget is rendered.
* Editing: When clicking on the cell (or pressing Enter on it) after it 
has been selected it enters editing mode and displays the appropriate 
widget.

The problem is the second state mentioned above and that brings me to my 
actual question: How can I get CellRenderer to enter editing mode as 
soon as it is selected?

I have tried testing the flags parameter (in on_render) for 
gtk.CELL_RENDERER_SELECTED and then calling self.start_editing() myself. 
I have confirmed that my on_start_editing() is indeed called, but that 
does not seem to be enough to put the cell in editing mode and show the 
widget.

This is has been solved in Virtaal (the application I'm working on), but 
it involved creating a custom TreeModel implementation. This model would 
return True for get_value() calls on the (hard-coded) column number of 
the editable property, only if the internal iterator matched the 
get_value() call's parameter. This is a big hack I'd like to avoid in my 
implementation. For this implementation the CellRenderer is in 
https://translate.svn.sourceforge.net/svnroot/translate/src/trunk/virtaal/virtaal/views/widgets/storeviewwidgets.py 
and the CellEditable is in 
https://translate.svn.sourceforge.net/svnroot/translate/src/trunk/virtaal/virtaal/views/unitview.py

Any insight would be greatly appreciated.

Thanks in advance,

-- 
Walter Leibbrandt                  Software Developer
Recent blogs:
* Firefox-style button with a pop-up menu
http://www.translate.org.za/blogs/walter/en/content/firefox-style-button-pop-menu