Adding widgets based on settings

main.py

from kivy.app import App
from kivy.factory import Factory
from kivy.lang import Builder
from kivy.properties import ObjectProperty
from kivy.uix.boxlayout import BoxLayout

Builder.load_string('''
<MilkshakeRoot>:
    milkshakes: box_with_milkshakes
    orientation: 'vertical'
    BoxLayout:
        id: box_with_milkshakes
        orientation: 'horizontal'
    Button:
        size_hint_y: 0.1
        text: 'Reset'
        on_press: app.root.reset_numbers()

<MilkshakeWidget>
    orientation: 'vertical'
    name: ''
    number_ordered: 0
    Button:
        # background_normal: root.name + '_small.png'
        on_press: root.increase_number()
    Label:
        size_hint_y: 0.2
        text: root.name
    Label:
        id: root.name
        size_hint_y: 0.4
        font_size: '40sp'
        text: str(root.number_ordered)
''')


class MilkshakeRoot(BoxLayout):
    milkshakes = ObjectProperty(None)

    def add_milkshake(self, name):
        milkshake = Factory.MilkshakeWidget()
        milkshake.name = name
        self.milkshakes.add_widget(milkshake)

    def reset_numbers(self):
        for milkshake in self.milkshakes.children:
            milkshake.number_ordered = 0
            ### speculative function call:
            # self.set_number(milkshake.name, 99)

    ### speculative function definition:
    def set_number(self, taste=None, my_special_number=0):
        if taste is not None:
            self.milkshakes[taste]['number_ordered'] = my_special_number


class MilkshakeWidget(BoxLayout):

    def increase_number(self):
        self.number_ordered += 1


class MilkshakeManiaApp(App):

    def build(self):
        root = MilkshakeRoot()
        milkshake_names = ['banana', 'chocolate', 'lemon']
        for milkshake_name in milkshake_names:
            root.add_milkshake(milkshake_name)
        return root


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