Python/Kivy - Sending variables from one class to another - python-3.x

Question

I'm not that new to Python so I have a basic understanding but I wouldn't say that I'm all that great either.
I've been having a tonne of problems with a brazilian jiujitsu app that I'm trying to make in Kivy. I am trying to get the text from a button that has been pressed in one window, and then use that text in a label for the next window that shows. The former window I have given the class name GuardWindow() and the latter window is called SweepSubTranPage().
I have managed to send the name of the button from my kivy file to the class GuardsWindow() easily enough, and the line self.guardlabel = instance.text works fine and retrieves the button name perfectly. My main problem however is sending that name over to the SweepSubTranPage() so that i can access it in my kivy file.
Here is the Python code:
class GuardsWindow(Screen):
guardButtonName = ObjectProperty(None)
def send_guard_type(self, instance, **kwargs):
self.guardButtonName = instance.text # retrieves the button name
def sender(self): # my attempt at sending it to the other class
return self.guardButtonName
class SweepSubTranPage(Screen):
pageTitle = ObjectProperty(None)
gw = GuardsWindow()
pageTitle.text = gw.sender()
kv = Builder.load_file("my.kv")
class MyMainApp(App):
def build(self):
return kv
if __name__ == "__main__":
MyMainApp().run()
And here is the Kivy file code:
<GuardsWindow>
name: "GuardsHomepage"
ScrollView:
bar_width: 10
do_scroll_x: False
do_scroll_y: True
scroll_type: ["bars", "content"]
BoxLayout:
orientation: "vertical"
size_hint: 1, 2
padding: 10
spacing: 10
Button: # these are the buttons that i am getting the text from
text: "Full Guard"
on_press:
root.send_guard_type(self) # this sends the button
on_release:
app.root.current = "SweepSubTranPage"
root.manager.transition.direction = "left"
Button:
text: "Half Guard"
on_press:
root.send_guard_type(self) # this sends the button
on_release:
app.root.current = "SweepSubTranPage"
root.manager.transition.direction = "left"
<SweepSubTranPage>
name: "SweepSubTranPage"
pageTitle: title
BoxLayout:
orientation: "horizontal"
size_hint: 1, 0.1
Label: # this is the label that I need the text for
id: title
font_size: 40
size_hint: 1, 1
When I run the code above, I get the error:
File "C:/Users/bensw/PycharmProjects/BJJ Tracker/main.py", line 36, in <module>
class SweepSubTranPage(Screen):
File "C:/Users/bensw/PycharmProjects/BJJ Tracker/main.py", line 40, in SweepSubTranPage
pageTitle.text = gw.sender()
AttributeError: 'kivy.properties.ObjectProperty' object has no attribute 'text'
I hope I have been clear enough in explaining my issue. If you have any questions please ask!
Thank you so much!!

Answer 1

In your send_guard_type() method you can access another Screen using the manager property of any Screen, and the get_screen() method of the ScreenManager. Something like this:
def send_guard_type(self, instance, **kwargs):
self.guardButtonName = instance.text # retrieves the button name
self.manager.get_screen("SweepSubTranPage").ids.title.text = instance.text