How do you pass variables between 2 classes in kivy? - python-3.x

Question

I recently started using kivy for my project.
I'm trying to make a simple digital coffee menu board.
I'm trying to display what a user have selected.
In MenuScreen, menu is presented to a user, which then a user can select.
After selection, I would like to move to another screen and display 'the selection' eg: Espresso
on top of the picture of a coffee cup.
I got to a stage where I can manually write a string value to be displayed.
But I wasn't able to display the selected name of the coffee by a user.
I'm literally stuck with this problem for 2 straight days or about 17hours of intense googling and reading documentations, but with my limited braincells, I wasn't able to solve it.
I've looked into binding, passing variables between 2 classes,etc.
Any help would be greatly appreciated!!
short version python code
class MenuScreen(Screen):
def __init__(self, **kwargs):
super(MenuScreen, self).__init__(**kwargs)
def buttonEspresso(self):
print ('Espresso Selected')
global selectedDrink
selectedDrink = self.coffeeName.text #<-------
sm.current = 'settings'
class SettingsScreen(Screen):
coffeeName = ObjectProperty(None)
def __init__(self, **kwargs):
super(SettingsScreen, self).__init__(**kwargs)
self.ids.coffeeName.text = selectedDrink #<-------
def backToMenu(self):
print('going back to menu')
sm.current = 'menu'
short version kivy code
:
coffeeName: coffeeName
GridLayout:
cols:2
GridLayout:
cols:2
Button:
id: coffeeName
text: 'Espresso'
on_press:
root.manager.transition = FadeTransition()
root.text = 'Espresso'
root.buttonEspresso()
<SettingsScreen>:
coffeeName: coffeeName
GridLayout:
cols:2
GridLayout:
cols:1
Button:
text: 'Back to menu'
size_hint: None, None
size: 200, 50
on_press:
root.manager.transition = SlideTransition(direction="left")
root.backToMenu()
Label:
id: coffeeName #<-------
text: 'coffeeName'
font_size: 70
size_hint: None, None
size: 960, 50
AnchorLayout:
anchor_x: 'center'
anchor_y: 'center'
Image:
source: 'cappuccino.png'
size_hint: None, None
size: 1000, 1000
If I select 'Espresso' then my desired outcome is
having 'Espresso' displayed in the red border.
Above image with myDesiredOutcome was made by editing
self.ids.coffeeName.text = selectedDrink #<-------
for illustration purpose
PythonCode
import kivy
from kivy.app import App
from kivy.logger import Logger
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.video import Video
from kivy.uix.label import Label
from kivy.uix.button import Button
from kivy.lang import Builder
from kivy.uix.widget import Widget
from kivy.properties import StringProperty
from kivy.properties import ObjectProperty
import subprocess
import os
from omxplayer.player import OMXPlayer
class Player(Video):
def __init__(self, **kwargs):
super(Player, self).__init__(**kwargs)
self.player = OMXPlayer('video.mp4','--loop')
self.state='play'
self.options={'eos': 'loop'}
self.bind(on_touch_down = self.on_stop)
def check(self):
Logger.info("film position:" + str(self.position))
def on_stop(self, *args):
print ('I have been clicked')
#self.state='stop' # stop the video
self.player.quit()
sm.current = 'menu' # switch to the other Screen
class MenuScreen(Screen):
#coffeeName = ObjectProperty(None)
def __init__(self, **kwargs):
super(MenuScreen, self).__init__(**kwargs)
def buttonEspresso(self):
print ('Espresso Selected')
global selectedDrink
selectedDrink = self.coffeeName.text #<-------
sm.current = 'settings'
def buttonAmericano(self):
print ('Americano Selected')
sm.current = 'settings'
def buttonCafeLatte(self):
print ('Cafe Latte Selected')
sm.current = 'settings'
def buttonCappuccino(self):
print ('Cappuccino Selected')
sm.current = 'settings'
def buttonCafeMocha(self):
print ('Cafe Mocha Selected')
sm.current = 'settings'
def buttonMochaccino(self):
print ('Mochaccino Selected')
sm.current = 'settings'
class SettingsScreen(Screen):
coffeeName = ObjectProperty(None)
def __init__(self, **kwargs):
super(SettingsScreen, self).__init__(**kwargs)
self.ids.coffeeName.text = selectedDrink #<-------
def backToMenu(self):
print('going back to menu')
sm.current = 'menu'
Builder.load_file('screenManager.kv')
sm = ScreenManager()
screen1 = Screen(name='video')
screen1.add_widget(Player())
sm.add_widget(screen1)
sm.add_widget(MenuScreen(name='menu'))
sm.add_widget(SettingsScreen(name='settings'))
class VideoPlayerApp(App):
def build(self):
return sm
if __name__ == "__main__":
video = VideoPlayerApp()
try:
video.run()
except KeyboardInterrupt:
video.stop()
os.system('killall dbus-daemon')
Kivy code
#:import FadeTransition kivy.uix.screenmanager.FadeTransition
#:import SlideTransition kivy.uix.screenmanager.SlideTransition
#:import GridLayout kivy.uix.gridlayout
<MenuScreen>:
coffeeName: coffeeName
GridLayout:
cols:2
GridLayout:
cols:2
Button:
id: coffeeName
text: 'Espresso'
on_press:
root.manager.transition = FadeTransition()
root.text = 'Espresso'
root.buttonEspresso()
Button:
text: 'Americano'
on_press:
root.manager.transition = FadeTransition()
root.buttonAmericano()
Button:
text: 'Cafe Latte'
on_press:
root.manager.transition = FadeTransition()
root.buttonCafeLatte()
Button:
text: 'Cappuccino'
on_press:
root.manager.transition = FadeTransition()
root.buttonCappuccino()
Button:
text: 'Cafe Mocha'
on_press:
root.manager.transition = FadeTransition()
root.buttonCafeMocha()
Button:
text: 'Mochaccino'
on_press:
root.manager.transition = FadeTransition()
root.buttonMochaccino()
GridLayout:
cols:2
Button:
text: 'Hot Chocolate'
on_press:
root.manager.transition = FadeTransition()
root.manager.current = 'settings'
#fading transition for video
Button:
text: 'Creamy Chocolate'
on_press:
root.manager.transition = FadeTransition()
root.manager.current = 'settings'
#fading transition for video
Button:
text: 'Express Coffee'
on_press:
root.manager.transition = FadeTransition()
root.manager.current = 'settings'
#fading transition for video
Button:
text: 'Green Tea'
on_press:
root.manager.transition = FadeTransition()
root.manager.current = 'settings'
#fading transition for video
Button:
text: 'Milk Tea'
on_press:
root.manager.transition = FadeTransition()
root.manager.current = 'settings'
#fading transition for video
Button:
text: 'Roibos Tea'
on_press:
root.manager.transition = FadeTransition()
root.manager.current = 'settings'
#fading transition for video
<SettingsScreen>:
coffeeName: coffeeName
GridLayout:
cols:2
GridLayout:
cols:1
Button:
text: 'Back to menu'
size_hint: None, None
size: 200, 50
on_press:
root.manager.transition = SlideTransition(direction="left")
root.backToMenu()
Label:
id: coffeeName #<-------
text: 'coffeeName'
font_size: 70
size_hint: None, None
size: 960, 50
AnchorLayout:
anchor_x: 'center'
anchor_y: 'center'
Image:
source: 'cappuccino.png'
size_hint: None, None
size: 1000, 1000
GridLayout:
cols:1
Label:
font_size: 70
text: 'Select a Payment Option'
size_hint: None, None
size: 960, 200
BoxLayout:
size_hint: None, None
size: 960, 50
ToggleButton:
text: 'Cash'
font_size: 50
on_press:
print('on_press')
ToggleButton:
text: 'UniPay'
font_size: 50
ToggleButton:
text: 'Bank Cards'
font_size: 50
BoxLayout:
Button:
text: 'Back to menu'
on_press:
root.manager.transition = SlideTransition(direction="left")
root.manager.current = 'menu'