from kivy.app import App
from kivy.uix.button import Button
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.textinput import TextInput

class Box1(BoxLayout):	
	btnOne = Button()
	btnTwo = Button()
	btnCal = Button()
	txtOne = TextInput()
	def calc(self, txt):
		txt.text = "Más"		
class TesztApp(App):
	def build(self):
		return Box1()
	def csinal(self):
		self.title ='valami'
	def vissza_csinal(self):
		self.title ='eredeti'
		
TesztApp().run()