struggling with python and Kivy -

i'm learning python , kivy , i'm struggling understand how call functions , continue functions kivy gui.

here .py:

import csv import os import easygui import kivy kivy.require('1.0.7')  kivy.app import app kivy.animation import animation kivy.uix.button import button kivy.uix.label import label kivy.uix.gridlayout import gridlayout kivy.uix.textinput import textinput  def csvimport(filename):     open(filename, 'rb') f:         reader = csv.reader(f)         your_list = list(reader)         return your_list  class loadfile(app):     def fileloadscreen(self):         self.add_widget(button(size_hint_y=(none), height=('48dp'), text='select file',                     on_press=self.importfile))      def importfile(self, instance):         filepath = easygui.fileopenbox()         if filepath!='.':             a=csvimport(filepath)             instance.text='file loaded'             instance.disabled=true  class loginbakapp(app):     def logauth(username,password):         if username!='' , password!='':             print('ok')     kv_directory = 'gui'  if __name__ == '__main__':     loginbakapp().run() 

and loginbak.kv:

#:kivy 1.9.0 gridlayout:     row_force_default: true     row_default_height: 40     rows: 3     cols: 2     padding: 10     spacing: 10     label:         id: userlabel         text: 'username:'     textinput:         id: username     label:         id: passwordlabel         text: 'password:'     textinput:         id: password         password: true     button:         id:btn_login         text: 'login'         on_press: print('ok') 

this code seems work without issues (when click login button, print 'ok'. tried swap out

on_press: logauth(username,password) 

and error logauth not defined.

ultimately, i'm trying model here (as first learning experience) hit login button , long fields not blank, display login success message 5 seconds , delete fields , call loadfile app (add button can clicked select , import file).

what doing wrong here? i've sifted through 60 scripts online , have been looking @ kivy examples hours , cannot figure out how i'm doing wrong. can point me in right direction and/or make suggestions creating/deleting gui described? i'm new kivy (and can code basic python scripts) little confusing when read of other questions on stackoverflow.

on_press: logauth(username,password) 

logauth method of app class, not function defined in kv namespace. can instead use app.logauth(...), app keyword references current app instance.