Get Values between Kivy screens on button click

Question

I have an Kivy app that has 2 screens. Screen 1 (ProblemWindow) will get the user input and screen 2 (StepsWindow) will show some images based on screen1 input. However, I need to pass one of the values (Spinner id: problem_id) from screen 1 (ProblemWindow) into screen 2 (StepsWindow) and also use the value in the python file for additional logic.

I can pass the value between the screens but I am not able to use it in python. I need to get the updated Label Text of the StepsWindow into my python code every time I change it in my ProblemWindow and press the button "ShowSteps".

Could anyone please guide me how to achieve this?

This is my python code:

# importing dependencies
from kivy.app import App
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.lang import Builder


class WindowManager(ScreenManager):
    pass

class ProblemWindow(Screen):
    def selected_problem(self, value):
        self.ids.click_label.text = f'selected problem: {value}'
        return value

class StepsWindow(Screen):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        # self.get_problem_name()
    
    def get_problem_name(self, *args):
        self.problem_name = self.ids.problem_name.text
        print(self.problem_name)

kv = Builder.load_file('main.kv')

class main(App):
    def build(self):
        return kv

if __name__ == '__main__':
    main().run()

This is my kv file for reference:

WindowManager:
    id: window_manager
    ProblemWindow:
        id: pw
    StepsWindow:
        id: sw

<ProblemWindow>:
    name: "problem_window"
    GridLayout:
        rows: 4
        Label:
            text: "TEST"
            font_size: 24
        Label:
            id: click_label
            text: "Select a problem"
        Spinner:
            id: problem_id
            text: "Problems List (Click here)"
            font_size: 24
            values: ["Problem_1", "Problem_2"]
            on_text: root.selected_problem(problem_id.text)
            size_hint: 0.1, 0.1
            width: 300
        Button:
            text: "Show Steps"
            font_size: 28
            size_hint: 0.2, 0.2
            pos_hint: {"center_x": 0.5, "center_y": 0.5}
            on_release:
                app.root.current = "steps_window"
                root.manager.transition.direction = "left"
<StepsWindow>:
    name: "steps_window"
    GridLayout:
        rows: 3
        size: root.width, root.height
        Label:
            id: problem_name
            text: root.manager.ids.pw.ids.problem_id.text
            font_size: '42'
            size_hint_y: None
            height: 50
        Button:
            text: "Back"
            on_release:
                app.root.current = "problem_window"
                root.manager.transition.direction = 'right'

Answer 1

Something like this?

# importing dependencies
from kivy.app import App
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.lang import Builder


class WindowManager(ScreenManager):
    pass


class ProblemWindow(Screen):

    def selected_problem(self, value):
        self.value = value
        self.ids.click_label.text = f'selected problem: {value}'
        return value

#logic here
    def logic_here(self):
        if self.value == "Problem_1":
            print(f'The solution for "Problem_1" is:')
        else:
            print(f'The solution for "Problem_2" is:')


class StepsWindow(Screen):

    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        # self.get_problem_name()

    def get_problem_name(self, *args):
        self.problem_name = self.ids.problem_name.text
        print(self.problem_name)

kv = Builder.load_file('main.kv')

class main(App):
    def build(self):
        return kv

if __name__ == '__main__':
    main().run()

And for the <ProblemWindow> button in the .kv file add this:

root.logic_here()