Re: Has anyone been able to force TreeView expander with no children?

["Daniel B. Thurman" <dant cdkkt com>]

On 10/14/2009 06:52 PM, Daniel B. Thurman wrote:
[snip!]

Apologies.  It appears that there is something wrong
with email-deliveries and I am not getting every
posting, so I will have to reply to certain individuals
that I have not received directly into my mailbox.
(I am looking directly at the archives for those I have missed)

====================================
David Nec(as <yeti physics muni cz>
(1) The signal is called "row-expanded".

[Dan] Thank you!  But how did you find this signal?

(2)  You have the text in another column instead of directly in the
expander column?

[Dan] I have posted the experimental code & hopefully the post is accepted.

====================================
Shaun McCance <shaunm gnome org>
(1)  If you want to populate data on-demand like this,
      you're probably going to have to write your own GtkTreeModel.

[Dan] Ugh.  I will try to use the stock and see if I can get this to
work first!

====================================
Holger Berndt <berndth gmx de> (sent directly to me)

The way I do that is to add a single dummy child (with a text like
"Loading..."). That makes the top level entry expandable. When
the user expands the item, he gets feedback right away by seeing the
"Loading..." entry, while the code populates the model on the fly, and
finally removes the dummy entry.

Others (e.g. Nautilus list view) seem to do it similarly.

[Dan- All below]

The problem I have is: how do I capture the signal when the
row is expanded?  I posted a follow up on this and it seems
that the key is "row-has-child-toggled", but this does not
seem to work:

self.treeview.connect('row-has-child-toggled', self.on_row_activated)
TypeError: <gtk.TreeView object at 0xb7b9ab6c (GtkTreeView at
0x8df5080)>: unknown signal name: row-has-child-toggled

I have, however tried:
self.treeview.connect('row-activated', self.on_row_activated)

and this works, except that the row has to be mouse
double-clicked, which is not what I want.

I sure wish there is a Python-GTK code somewhere
that I could peruse to resolve my many issues!

Since the code I have is experimental, I include it
in the following, so that it is open to critique and
may be of benefit to others following the same
pathway:

==================================
[code]
#!/usr/bin/env python

import os, stat, sys, time
import pygtk
pygtk.require('2.0')
import gtk

DEBUG=True
RECURSE=1
SEP='                  '

DEFAULT_PATH='~/Desktop/'

class FileLister:

#    column_names = ['Files', 'Size', 'Mode', 'Last Changed', 'Path']
    column_names = ['Files']

    # Close the window and quit
    def delete_event(self, widget, event, data=None):
        gtk.main_quit()
        return False

    def __init__(self, path=None):
       
        cell_data_funcs = (
            None,
            self.file_size,
            self.file_mode,
            self.file_last_changed,
            self.file_path)
       
        # Create a new window
        self.window = gtk.Window(gtk.WINDOW_TOPLEVEL)
        self.window.set_title("FileLister")
        self.window.set_size_request(600, 400)
        self.window.connect("delete_event", self.delete_event)

        # TreeView
        self.treestore = gtk.TreeStore(str, gtk.gdk.Pixbuf, int, bool, str)
        self.treeview = gtk.TreeView(self.treestore)

        # TreeView Options
        self.treeview.set_level_indentation(0)
        self.treeview.set_show_expanders(True)
#        self.treeview.set_hover_expand(True)
#        self.treeview.set_search_column(0)
#        self.treeview.set_reorderable(True)

        # TreeViewColumns
        self.tvcolumn = [None] * len(self.column_names)
        cellpb = gtk.CellRendererPixbuf()
        self.tvcolumn[0] = gtk.TreeViewColumn(self.column_names[0], cellpb)
        self.tvcolumn[0].set_cell_data_func(cellpb, self.file_pixbuf)
        cell = gtk.CellRendererText()
        self.tvcolumn[0].pack_start(cell, False)
        self.tvcolumn[0].set_cell_data_func(cell, self.file_name)
        self.treeview.append_column(self.tvcolumn[0])
        # Append more TreeView columns, if available       
        for n in range(1, len(self.column_names)):
            cell = gtk.CellRendererText()
            self.tvcolumn[n] = gtk.TreeViewColumn(self.column_names[n],
cell)
            if n == 1:
                cell.set_property('xalign', 0.0)
            self.tvcolumn[n].set_cell_data_func(cell, cell_data_funcs[n])
            self.treeview.append_column(self.tvcolumn[n])

        # Signals
#        self.treeview.connect('row-activated', self.on_row_activated)
        ''' FOLLOWING DOES NOT WORK '''
        self.treeview.connect('row-has-child-toggled',
self.on_row_activated)
       
        # Populate TreeView with initial files
        self.path = os.path.expanduser(DEFAULT_PATH)
        self.dir_walk(path=self.path, recurse=RECURSE)

        # Add scrolled Window
        self.scrolledwindow = gtk.ScrolledWindow()
        self.scrolledwindow.add(self.treeview)
        self.window.add(self.scrolledwindow)

        # Display the window
        self.window.show_all()

    # Populate TreeStore with directory listing
    def dir_walk(self, path, parent=None, recurse=0):
        filestat = os.stat(path)
        if not stat.S_ISDIR(filestat.st_mode):
            self.debug("File     : "+path)
            return self.treestore
        for f in os.listdir(path):
            rec=recurse
            filename = os.path.join(path, f)
            fdata = os.stat(filename)
            is_folder = stat.S_ISDIR(fdata.st_mode)
            if is_folder:
                fType="Directory"
                hdr="%s: %s" % (fType, filename)
            else:
                fType="File"
                hdr="%s     : %s" % (fType, filename)
            self.debug(hdr)
            img = gtk.icon_theme_get_default().load_icon(
                    "folder" if is_folder else "document",
                    gtk.ICON_SIZE_MENU, 0)
            try:
                ts = self.treestore.append(parent, [f,img,fdata.st_size,
is_folder, path])
            except Exception, error:
                ''' Note: exceptions occurs on certain files on
Fedora-11 mounted NTFS filesystem <Needs investigating...> '''
                extradata="Filename=%s\n%sFiletype=%s\n%sparent=%s,
[f=%s, img=%s, size=%s, is_folder=%s, path=%s]" % (filename, SEP, fType,
SEP, parent, f, img, fdata.st_size, is_folder, path)  
                self.dump_traceback(extradata)
                continue
            if is_folder and rec > 0:
                rec=rec-1
                self.dir_walk(path=filename, parent=ts, recurse=rec)
        return self.treestore

    def on_row_activated(self, treeview, path, column):
        model = treeview.get_model()
        iter = model.get_iter(path)
        filename = os.path.join(model.get_value(iter, 4),
model.get_value(iter, 0))
        #self.debug("File     : "+filename)
        ts = self.dir_walk(filename, parent=iter, recurse=1)
        treeview.set_model(ts)
        return

    def file_pixbuf(self, column, cell, model, iter):
        filename = os.path.join(model.get_value(iter, 4),
model.get_value(iter, 0))
        filestat = os.stat(filename)
        if stat.S_ISDIR(filestat.st_mode):
            pb = gtk.icon_theme_get_default().load_icon("folder",
gtk.ICON_SIZE_MENU, 0)
        else:
            pb = gtk.icon_theme_get_default().load_icon("document",
gtk.ICON_SIZE_MENU, 0)
        cell.set_property('pixbuf', pb)
        return

    def file_name(self, column, cell, model, iter):
        cell.set_property('text', model.get_value(iter, 0))
        return

    def file_size(self, column, cell, model, iter):
        filename = os.path.join(model.get_value(iter, 4),
model.get_value(iter, 0))
        filestat = os.stat(filename)
        cell.set_property('text', filestat.st_size)
        return

    def file_mode(self, column, cell, model, iter):
        filename = os.path.join(model.get_value(iter, 4),
model.get_value(iter, 0))
        filestat = os.stat(filename)
        cell.set_property('text', oct(stat.S_IMODE(filestat.st_mode)))
        return

    def file_last_changed(self, column, cell, model, iter):
        filename = os.path.join(model.get_value(iter, 4),
model.get_value(iter, 0))
        filestat = os.stat(filename)
        cell.set_property('text', time.ctime(filestat.st_mtime))
        return
   
    def file_path(self, column, cell, model, iter):
        filename = os.path.join(model.get_value(iter, 4),
model.get_value(iter, 0))
        cell.set_property('text', filename)
        return

    def debug(self, string):
        if DEBUG:
            print 'DEBUG: %s' % string
           
    def dump_traceback(self, extradata=None):
        import traceback
        etb = traceback.extract_tb(sys.exc_info()[2])
        traceback = 'Traceback:\n'
        for tub in etb:
            f, l, m, c = tub # file, lineno, function, codeline
            traceback += '                  '+('File: %(a)s, line %(b)s,
in %(c)s\n') % {'a': f, 'b': l, 'c': m}
            traceback += '                  %s \n' % c
            traceback += '                  %s: %s' %
(sys.exc_info()[0], sys.exc_info()[1]) #etype, evalue
        print "ERROR: Exception: %s\n%s%s" % (traceback, SEP,
extradata)               
   
def main():
    gtk.main()

if __name__ == "__main__":
    myApp = FileLister()
    main()
[/code]