how to switch screens in kivy
from kivy.uix.screenmanager import ScreenManager, Screen
# Create the manager
sm = ScreenManager()
# Add few screens
for i in range(4):
screen = Screen(name='Title %d' % i)
sm.add_widget(screen)
# By default, the first screen added into the ScreenManager will be
# displayed. You can then change to another screen.
# Let's display the screen named 'Title 2'
# A transition will automatically be used.
sm.current = 'Title 2'