Re: GtkBuilder and GtkTextView buffer text

[Kevin Hunter <hunteke gmail com>]

At 12:52am -0500 Thu, 13 Dec 2012, Tristan Van berkom wrote:
> Your Glade file does not declare any GtkTextBuffer (so you need to
> add a text buffer in your Glade file and set the 'buffer' property
> of that view to refer to that buffer)... so view.get_buffer() returns
> NULL.

Huh.  That's not what I am seeing when I piddle around with IPython. 
The docs suggest that if I don't supply one, one is created 
automatically.  I'm having a difficult time finding the documentation 
for this version of the Python bindings.

For reference:

  $ python3 --version
  Python 3.2.3

  $ cat | python3
  from gi.repository import Gtk
  print(Gtk.MAJOR_VERSION, Gtk.MINOR_VERSION)
  3 4

However, I think this is the C backend function:

http://developer.gnome.org/gtk3/3.4/GtkTextView.html#gtk-text-view-new

  "If you don't call gtk_text_view_set_buffer() before using the
   text view, an empty default buffer will be created for you."

Am I missing a nuance there?  With both an embedded shell at the problem 
point and with print() statements, it /looks/ like the get_buffer() 
function ...

  # self.vText is a reference to the GtkTextView object
  #   I have yet to put anything in the view's buffer.  Now:
  buf = self.vText.get_buffer()
  print( type(buf) )
  print( buf )

... returns an instantiated object:

  <class 'gi.overrides.Gtk.TextBuffer'>
  <TextBuffer object at 0x34fb410 (GtkTextBuffer at 0x2788ec0)>

Unfortunately, the department of "It's not working!" is telling me 
otherwise.

So, I of course tried your suggestion of putting this in my Glade XML file:

  <object class="GtkTextBuffer" id="bText"/>
  ...
  <object class="GtkTextView" id="vText">
   <property name="can_focus">False</property>
   <property name="wrap_mode">word</property>
   <property name="buffer">bText</property>
  </object>

Same issue: a core dump immediately after returning to C after calling 
set_text on the buffer.

So ... am I missing something else?  (Very possible!)

Perhaps the object as understood by Python is not indicative of the 
actual C backed GtkTextBuffer, and I need to specifically instantiate 
one for it?  (If so, why?!)

> A suggestion:
>
> Don't keep your GtkBuilder object alive for your program lifetime,
> just create it in your constructor, save and *check* all the objects
> you might need at construction time and then refer to those objects
> as instance  members throughout your object's lifetime.

All good points, and well taken.  Thank you for sharing.  I was mainly 
thinking along the lines of showing what I had tried because I'm so very 
new to Gtk.  I.e., less about "quality" and more about making sure the 
list saw all my little oversights.  (Like the lack of a GtkTextBuffer.

Thanks so much for your help!

Kevin