PyGTK Entry widget in TreeViewColumn header

Question

How can I make a gtk.Entry widget focusable or editable within a gtk.TreeViewColumn header/title? I've tried this:

# Create tree-view.
treeview = gtk.TreeView()

#...

# Create column.
renderer = gtk.CellRendererText()
column = gtk.TreeViewColumn(None, renderer, text=0)

# Set column header.
header = gtk.VBox()

title = gtk.Label("Column")
header.pack_start(title)

filter = gtk.Entry()
#...
header.pack_start(filter)

header.show_all()
column.set_widget(header)

# Add column
treeview.append_column(column)

But the Entry widget in the column header is not editable and will not focus. I've tried setting 'clickable' to both True and False. I'm using pygtk 2.21.0-0ubuntu1 and libgtk 2.22.0-0ubuntu1 on Ubuntu 10.04. Any help would be greatly appreciated.

EDIT:

The issue stems from how a GtkTreeViewColumn header is displayed. The header widget is placed inside a GtkAlignment whose parent is a GtkHBox whose parent is a GtkButton whose parent is finally the GtkTreeView. The GtkButton is intercepting and preventing my GtkEntry from being focused and receiving mouse input.

Answer 1

In order to make a GtkEntry focusable within a GtkTreeView header I had to:

1) Find the header GtkButton.

def find_closest_ancestor(widget, ancestor_class):
    if not isinstance(widget, gtk.Widget):
        raise TypeError("%r is not a gtk.Widget" % widget)
    ancestor = widget.get_parent()
    while ancestor is not None:
        if isinstance(ancestor, ancestor_class):
            break;
        ancestor = ancestor.get_parent() if hasattr(ancestor, 'get_parent') and callable(ancestor.get_parent) else None
    return ancestor

2) Propagate the button-press-event signal from the header GtkButton to the GtkEntry.

def propagate_button_press_event(parent, event, *data):
    parent_alloc = parent.get_allocation()
    x = parent_alloc.x + int(event.x)
    y = parent_alloc.y + int(event.y)
    children = parent.get_children()
    print "Propagating event:%r" % event
    print "- from parent:%r" % parent
    while children:
        for child in children:
            child_alloc = child.get_allocation()
            if child_alloc.x <= x <= child_alloc.x + child_alloc.width and child_alloc.y <= y <= child_alloc.y + child_alloc.height:
                print "- to child:%r" % child
                if child.get_property('can-focus'):
                    event.send_event = True
                    child.grab_focus()
                    child.emit('button-press-event', event, *data)
                    return True
                else:
                    children = child.get_children() if hasattr(child, 'get_children') and callable(child.get_children) else None
                    break;
        else:
            children = None
    return False

3) Propagate the focus (i.e., focus-in-event signal) from the header GtkButton to the GtkEntry.

def propagate_focus_in_event(parent, event, *data):
    print 'focus-in', parent, event
    child = parent.get_child()
    if child.get_property('can-focus'):
        child.grab_focus()
    else:
        if not child.child_focus(gtk.DIR_TAB_FORWARD):
            parent.get_toplevel().child_focus(gtk.DIR_TAB_FORWARD)
    return True

Example:

# Fix style glitches
_gtk_styles = """
    # Use the default GtkEntry style for GtkEntry widgets in treeview headers.
    widget "*.treeview-header-entry" style "entry" 
"""
gtk.rc_parse_string(_gtk_styles)

# Columns
_columns = [
    (0, "Title"),
    (1, "Description")
    # etc.
]

# Create tree-view.
items_view = gtk.TreeView(self.items_store)
items_view.show()

# Setup treeview columns.
renderer = gtk.CellRendererText()
for column in _columns:
    column_index, column_title, column_filter = column
    column_view = gtk.TreeViewColumn(None, renderer, text=column_index)
    column_view.set_clickable(True)

    column_widget = gtk.VBox()
    column_widget.show()

    column_align = gtk.Alignment(0, 0, 0, 0)
    column_align.show()
    column_widget.pack_start(column_align)
    column_label = gtk.Label(column_title)
    column_label.show()
    column_align.add(column_label)

    column_entry = gtk.Entry()
    column_entry.set_name('treeview-header-entry')
    column_entry.show()
    column_widget.pack_start(column_entry)

    column_view.set_widget(column_widget)
    items_view.append_column(column_view)

# Setup column headers.
columns = items_view.get_columns()
for column in columns:
    column_widget = column.get_widget()
    column_header = find_closest_ancestor(column_widget, gtk.Button)
    if column_header:
        column_header.connect('focus-in-event', propagate_focus_in_event)
        column_header.connect('button-press-event', propagate_button_press_event)
        column_header.set_focus_on_click(False)