How to communicate between screen modes ?

[dchapon]

I have a basic app with a couple of screen modes (so... separate screen stacks as I understand it). The default mode is dashboard. I would like to bind the reactive attribute current_obj_id of the App (which can be updated in the DashboardScreen) to the SettingsScreen reactive attribute obj_id.

How should I proceed ? Is Message/Event the preferred way to go instead ?

class SettingsScreen(Screen):
    obj_id: reactive[int] = reactive(None)




class MyApp(App[None]):
    MODES = {"dashboard": DashboardScreen,
             "settings": SettingsScreen,
             "help": HelpScreen}
    DEFAULT_MODE = "dashboard"
    current_obj_id: reactive[int] = reactive(None)

[Zaloog]

Hi @dchapon
You can get a specific screen with app.get_screen
In your case e.g.

self.get_screen("settings").data_bind(obj_id=MyApp.current_obj_id)

[dchapon]

Unfortunately,
When I try the self.get_screen("settings") in the App.on_mount() or in the App.on_ready() or App.compose() method, I get the error :

KeyError: "No screen called 'settings' installed"

Probably because upon startup, the default screen stack that is loaded is the stack containing the DashboardScreen.

[Zaloog]

I know you can use the SCREENS var in your app to install Screens directly, but I dont know exactly how that interacts with the MODES.

I guess it shouldnt cause any hickups, since the app calls install_screen anyway on first switch to a specific screen.
So I guess you can just pass your Screens to SCREENS.