GtkTreeViewColumn/CellLayout: get/modify attributes?

[Roland Koebler <rk-list simple-is-better org>]

Hi,

I need to dynamically modify TreeViews, e.g. to determine which
attributes are set in the GtkBuilder-file, and to show a different
model-column in a view-column. But I don't know how:

When I create GtkTreeViewColumns and GtkCellRenderers, I can
set "attributes", to tell the renderer which data to display,
e.g. (in Python, see end-of-mail for complete example):

store    = Gtk.ListStore(str, str, int)
tree     = Gtk.Treeview(store)
renderer = Gtk.CellRendererText()
column   = Gtk.TreeViewColumn("Test", renderer, text=0, weight=2)
tree.append_column(column)

The attributes here are "text=0" and "weight=2"

Now:
- How can I determine which attributes are set? I would like
  something like:
 
  >>> attrs = column.get_attributes(renderer)
  >>> print(attrs)
  {"text": 0, "weight": 2}

- How can I retrieve the attributes back from the tree/column/renderer?
  I would like something like:

  >>> textattr = column.get_attribute(renderer, "text")
  >>> print(textattr)
  0

- How can I modify a single attribute without clearing the others?
  I would like something like:

  >>> column.add_attribute(renderer, "text", 1)

  But this fails since the "text"-attribute is already set.


thanks,
Roland



PS: Complete example:

#!/usr/bin/python

from gi.repository import Gtk

# create window
win = Gtk.Window()
win.connect("delete-event", Gtk.main_quit)

# create treestore
store = Gtk.ListStore(str, str, int, int)
store.append(["Text",  "Other text",  400, 1000])
store.append(["Text2", "Other text2", 1000, 400])

# create treeview
tree     = Gtk.TreeView(store)
renderer = Gtk.CellRendererText()
column   = Gtk.TreeViewColumn("Test", renderer, text=0, weight=2)
tree.append_column(column)


# TODO: get attribute-list
#attrs = column.get_attributes()
#print(attrs)
# -> {"text": 0, "weight": 2}

# TODO: get attribute
#textattr = column.get_attributes("text")
#print(textattr)
# -> 0

# TODO: modify attributes
column.add_attribute(renderer, "text", 1)
# fails with "...Cannot connect attribute `text' for cell renderer class `GtkCellRendererText' since `text' 
is already attributed to column 0"


# run
win.add(tree)
win.show_all()
Gtk.main()