class Test(object):
  def __init__(self, attr):
    self.attr = attr

class LoginScreen(GridLayout):
  def __init__(self, **kwargs):
    super(LoginScreen, self).__init__(**kwargs)
    self.cols = 2
    self.add_widget(Label(text='User Name'))
    self.username = TextInput(multiline=False)
    self.add_widget(self.username)
    self.add_widget(Label(text='password'))
    self.password = TextInput(password=True, multiline=False)
    self.add_widget(self.password)
    print self.username.text

class Login(App):

  def build(self):
    Window.borderless = True
    return LoginScreen()

import classtest, gui
users = ['user_name1', 'user_name2', 'user_name3']
gui.Login().run()
for u in users:
  test = classtest.Test(u) # this should update the user text field on the windows login automatically, but how?