How to change screen by calling a method in Python Kivy - python-3.x

Question

I'm new to kivy and I want to change my screen by clicking the image. I used the ButtonBehavior and call the on_press method of my class ImageButton but I can't figure it out what code to put. I tried on_press: screen_manager.current = 'window1' on my kivy file but its not working
Python Code
from kivy.app import App
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.image import Image
from kivy.uix.behaviors import ButtonBehavior
class Window1(Screen):
pass
class Window2(Screen):
pass
class WindowManager(ScreenManager):
pass
class ImageButton(ButtonBehavior, Image):
def on_press(self):
# what to call
class Phone(FloatLayout):
pass
class MyApp(App):
def build(self):
return Phone()
if __name__ == '__main__':
MyApp().run()
kv file
<Phone>:
AnchorLayout:
anchor_x: 'center'
anchor_y: 'top'
WindowManager:
id: screen_manager
size_hint: 1, 0.9
anchor_y: 'top'
transition: FadeTransition()
Window1:
Window2:
AnchorLayout:
anchor_x: 'center'
anchor_y: 'bottom'
BoxLayout:
canvas:
Color:
rgba: 228, 241, 254, 1
Rectangle:
size: self.size
orientation: 'horizontal'
size_hint: 1, .1
ImageButton:
source: 'pic1.png'
on_press: self.on_press()
ImageButton:
source: 'pic2.png'
on_press: self.on_press()
<Window1>:
name: 'window1'
Label:
text: 'Window1'
<Window2>:
name: 'window2'
Label:
text: 'Window2'

Answer 1

Some one help me on this.. what im missing is in my kv file i should put
on_press: app.root.ids._screen_manager.current = 'window1'
Here is the explanation
When the kv code is parsed, the id fields go into a dict called ids, that stores pointers to the widget objects.
Each kivy rule has a sperate name space for ids.
Breaking it down:
app.root.ids.screen_manager
app is your app
root is the root widget, Phone
ids is the dict of ids defined at the root level
Credit for Elliot Garbus