Selection in GtkTextBuffer

I've recently played around with GtkTextBuffer. It's a rather nice text editing widget (or rather widget part). Unfortunately it misses one functionality, which is also missing from GtkEditable derived widgets: A signal for selection changes. There are two workarounds:

1. You can setup a notification on the has-selection property like this:

   buffer.connect("notify", on_buffer_notify)
   
   def on_buffer_notify(buffer, prop):
       if prop.name == "has-selection":
           if buffer.get_has_selection():
               ...
           else:
               ...
   

   This method only works if you are interested in whether there is a selection or not, not if you are interested in any selection changes. Also, this method works only for GtkTextBuffers, not for GtkEditables.

2. Tomboy uses a timeout to check the selection status:

   namespace Tomboy
   {
       public class NoteWindow : ForcedPresentWindow
       {
                   ...
           public NoteWindow (Note note) :
               base (note.Title)
           {
                           ...
               // Sensitize the Link toolbar button on text selection
               mark_set_timeout = new InterruptableTimeout();
               mark_set_timeout.Timeout  = UpdateLinkButtonSensitivity;
                           ...
                   }
   
                   ...
   
           void UpdateLinkButtonSensitivity (object sender, EventArgs args)
           {
               link_button.Sensitive = (note.Buffer.Selection != null);
           }
   
                   ...
           }
   }
   

This method works, but seems a bit complicated, when a simple signal should do the trick.

Filed as bug #448261.

by Miroslav Rajcic
Thursday, 19 July 2007 08:55

Just stumbled on your blog and seen your problem.

Signal notification of selection change works fine for me with following code:

//track movement of "insert" and "selection_bound" marks,

g_signal_connect (buffer, "mark-set", G_CALLBACK(textview_selection_changed), NULL);

....

void textview_selection_changed(GtkTextBuffer *textbuffer, GtkTextIter *arg1, GtkTextMark *arg2, gpointer user_data);