如何在 KivyMD (Python) 中结合导航抽屉和多个屏幕？

Question

I'm a coding beginner and I want to make a mobile app which contains a Toolbar with a Navigation Drawer and that one should bring the user to different screens in the app. I searched a lot around for a solution, but didn't really found one, because sometimes the whole code is in the.kv file, so it is hard to handle variables and print them for example such as in this code:

How to switch between screens within the NavigationDrawer using KivyMD

I tried to combine it with this code which uses only Kivy instead of KivyMD but I failed bacause it isn't really for mobile Apps:

https://www.techwithtim.net/tutorials/kivy-tutorial/multiple-screens/

I hope someone can help me. Thx!

Answer 1

from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import ObjectProperty

from kivymd.app import MDApp

KV = '''
<ContentNavigationDrawer>:

    ScrollView:

        MDList:

            OneLineListItem:
                text: "Screen 1"
                on_press:
                    root.nav_drawer.set_state("close")
                    root.screen_manager.current = "scr 1"

            OneLineListItem:
                text: "Screen 2"
                on_press:
                    root.nav_drawer.set_state("close")
                    root.screen_manager.current = "scr 2"


Screen:

    MDToolbar:
        id: toolbar
        pos_hint: {"top": 1}
        elevation: 10
        title: "MDNavigationDrawer"
        left_action_items: [["menu", lambda x: nav_drawer.set_state("open")]]

    MDNavigationLayout:
        x: toolbar.height

        ScreenManager:
            id: screen_manager

            Screen:
                name: "scr 1"

                MDLabel:
                    text: "Screen 1"
                    halign: "center"

            Screen:
                name: "scr 2"

                MDLabel:
                    text: "Screen 2"
                    halign: "center"

        MDNavigationDrawer:
            id: nav_drawer

            ContentNavigationDrawer:
                screen_manager: screen_manager
                nav_drawer: nav_drawer
'''


class ContentNavigationDrawer(BoxLayout):
    screen_manager = ObjectProperty()
    nav_drawer = ObjectProperty()


class TestNavigationDrawer(MDApp):
    def build(self):
        return Builder.load_string(KV)


TestNavigationDrawer().run()

https://kivymd.readthedocs.io/en/latest/components/navigation-drawer/#switching-screens-in-the-screenmanager-and-using-the-common-mdtoolbar

Answer 2

I have a problem, when I try to add a command to a button inside the screen it says: " AttributeError: 'Screen' object has no attribute 'cl'"(cl is the name of the command)