How to pass params when switch_mode(create screen object)?

[Yurii-huang]

I have two screen class types, named 'base' and 'edit','edit' needs to get some interface parameters from 'base' and dynamically generate interface 'edit', I try to use switch_mode and push_screen it seems that I can only pass the class type of 'base', and I can't get the instantiated object.

What should I do if I want to generate and toggle 'edit' via the argument of 'base'?

[TomJGooding]

Sorry but I don't understand your question. Perhap a MRE (short example) would help demonstrate what you mean?

[Yurii-huang]

class Edit(Screen):
    def __init__(self, data:str):
        self.data = data
    def on_mount(self):
        // use self.data do anything

MODES = {
"base": Base,
"edit": Edit
}

class Edit __init__ method need param: data, when i call swith_mode("edit"), it's not support
How to pass param: data?

[TomJGooding]

I think the problem might be that you forgot to call `super().init(). Here's a quick example based on the code above which seems to work okay?

from textual.app import App, ComposeResult
from textual.widgets import Placeholder, Footer
from textual.screen import Screen


class Edit(Screen):
    def __init__(self, data: str):
        self.data = data
        super().__init__()

    def compose(self) -> ComposeResult:
        yield Placeholder(self.data)
        yield Footer()


class ModesApp(App):
    BINDINGS = [
        ("f", "switch_mode('foo')", "Foo"),
        ("b", "switch_mode('bar')", "Bar"),
        ("z", "switch_mode('baz')", "Baz"),
    ]

    MODES = {
        "foo": Edit("Foo"),
        "bar": Edit("Bar"),
        "baz": Edit("Baz"),
    }

    def on_mount(self) -> None:
        self.switch_mode("foo")


if __name__ == "__main__":
    app = ModesApp()
    app.run()

[tsingwang]

I think it can't work in latest version. MODES and SCREENS should contain a Screen type or callable, not an instance.

[willmcgugan]

At the time of the accept answer, Textual accepted instances of screens in the SCREENS classvar. This won't work in the current version.

The solution is to replace the screen instances with a callable that returns an instance. The simplest edit would be to replace the screens with lambda functions.

from textual.app import App, ComposeResult
from textual.widgets import Placeholder, Footer
from textual.screen import Screen


class Edit(Screen):
    def __init__(self, data: str):
        self.data = data
        super().__init__()

    def compose(self) -> ComposeResult:
        yield Placeholder(self.data)
        yield Footer()


class ModesApp(App):
    BINDINGS = [
        ("f", "switch_mode('foo')", "Foo"),
        ("b", "switch_mode('bar')", "Bar"),
        ("z", "switch_mode('baz')", "Baz"),
    ]

    MODES = {
        "foo": lambda: Edit("Foo"),
        "bar": lambda: Edit("Bar"),
        "baz": lambda: Edit("Baz"),
    }

    def on_mount(self) -> None:
        self.switch_mode("foo")


if __name__ == "__main__":
    app = ModesApp()
    app.run()