python-gtk treeview-liststore实时更新

我在尝试获取实时更新时遇到了一个问题,我创建了一个示例来模拟我想做的事情。

http://img204.imageshack.us/i/capturadetela5.png/

它应该更新treeview列“speed”,并每秒给它一个不同的数字,

import gtk
import gtk.glade
import random

builder = gtk.Builder()
builder.add_from_file('ttt.glade')
window = builder.get_object('window1')
treeview  = builder.get_object('treeview1')
store = builder.get_object('liststore1')
column_n = ['File','Size','Speed']
rendererText = gtk.CellRendererText()


for i in range(10):
    foo = random.randint(100,256)
    list_ =  [('arquivo1.tar.gz', '10MB', '%s k/s' % foo)]

for x,y in zip(column_n,range(3)):

    column = gtk.TreeViewColumn(x, rendererText, text=y)
    column.set_sort_column_id(0)    
    treeview.append_column(column)


for list_index in list_:
    store.append([list_index[0],list_index[1],list_index[2]])

window.show_all()