Toggling Checkbox on a ModalScreen when key is pressed

[msempere]

Hi! I'm playing with the recently added ModalScreen and the Checkbox widget and I have noticed I can toggle a checkbox in the on_mount with self.query_one("#checkbox-0", Checkbox).toggle() but I cannot do the same as part of the on_key. Is that a expected behaviour?

The following code doesn't toggle the widget:

def on_key(self, event: Key):
    self.query_one("#checkbox-0", Checkbox).toggle()

While this does:

def on_mount(self):
    self.query_one("#checkbox-0", Checkbox).toggle()

[davep]

Do you think you could post a minimal working example of code that shows the issue you're seeing? I just tested with this:

from textual.app     import App, ComposeResult
from textual.widgets import Header, Footer, Checkbox

class CBKeyToggleApp( App[ None ] ):

    CSS = """
    Screen {
        align: center middle;
    }
    """

    def compose( self ) -> ComposeResult:
        yield Header()
        yield Checkbox("This is a test Checkbox", id="toggle-me")
        yield Footer()

    def on_key(self) -> None:
        self.query_one("#toggle-me", Checkbox).toggle()

if __name__ == "__main__":
    CBKeyToggleApp().run()

and it toggles the Checkbox just fine on any key.

Could you also post details of the exact steps you're taking too? For example, I can reproduce the issue you're seeing if I:

1. Run the above code.
2. Hit Tab to focus the Checkbox
3. Press either Space or Enter

In this case the above would be the expected behaviour because those are the key bindings for toggling a Checkbox so having an on_key also toggle it and then having the user press either of those keys would result in a double toggle.

[msempere]

Mmm interesting. I don't know what I was doing wrong before but I can verify it's working now.
Out of curiosity now that you've mentioned the double toggle, is the a way to replace a parent binding? in this case, make use of space or enter without the toggle? or just by setting the on_key to use space, per example, overwrites the parent binding?

[davep]

What do you mean exactly when you say "replace a parent binding"? Are you creating a custom Checkbox by inheriting from it? Perhaps it would be helpful if you explained what you're trying to do rather then how you're trying to do it so I can better understand?

I think the thing that has me a wee be confused is, if Checkbox already toggles using the keys you want to be used to toggle a Checkbox, why would you implement capturing those keys to toggle a Checkbox?