Cartouche

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

# Create both screens. Please note the root.manager.current: this is how
# you can control the ScreenManager from kv. Each screen has by default a
# property manager that gives you the instance of the ScreenManager used.
Builder.load_string("""
<MenuScreen>:
    BoxLayout:
        Button:
            text: 'Commande'
            on_press: root.manager.current = 'commande'
        Button:
            text: 'Nouveau Produit'
            on_press: root.manager.current = 'produit'
        Button:
            text: 'Statistiques'
            on_press: root.manager.current = 'stats'
        Button:
            text: 'Goto settings'
            on_press: root.manager.current = 'settings'
        Button:
            text: 'Quit'
<ProduitScreen>:
    GridLayout:
        rows: 3
        cols: 2
        padding: 10
        spacing: 10
        Label:
            font_size: 20
            text: 'Nom du produit'
        TextInput:
            font_size: 20
            id: nom
        Label:
            font_size: 20
            text: 'Prix'
        TextInput:
            font_size: 20
            id: prix
        Button:
            text: 'Ajouter'
            on_press: self.ajouter()
        Button:
            text: 'Quitter'
            on_press: root.manager.current = 'menu'

<CommandeScreen>:
    GridLayout:
        rows: 4
        cols: 2
        Label:
            text: 'Prix : '
        Label:
            text: '0.00 Euros'
        Button:
            text: 'Coca'
        Label:
            text: '1.80 euros'
        Button:
            text: 'Orangina'
        Label:
            text: '1.80 euros'
        Button:
            text: 'Ajouter'
        Button:
            text: 'Quitter'
            on_press: root.manager.current = 'menu'

<StatsScreen>:
    Button:
        text: 'Quitter'
        on_press: root.manager.current = 'menu'

<SettingsScreen>:
    BoxLayout:
        Button:
            text: 'My settings button'
        Button:
            text: 'Back to menu'
            on_press: root.manager.current = 'menu'
""")

# Declare both screens
class MenuScreen(Screen):
    pass

class ProduitScreen(Screen):
    def ajouter():
        print "%s au prix de %d a ete ajoute" % (self.nom.txt , float(self.prix.txt))

class CommandeScreen(Screen):
    pass

class StatsScreen(Screen):
    pass

class SettingsScreen(Screen):
    pass

# Create the screen manager
sm = ScreenManager()
sm.add_widget(MenuScreen(name='menu'))
sm.add_widget(SettingsScreen(name='settings'))
sm.add_widget(ProduitScreen(name='produit'))
sm.add_widget(CommandeScreen(name='commande'))
sm.add_widget(StatsScreen(name='stats'))

class TestApp(App):

    def build(self):
        return sm

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