Clear RadioButton selection in a RadioSet

[Daniel-Chin]

When the app initializes, it is possible that no RadioButton is selected in a set of RadioButtons. In this state, each radioButton.value == False and the radioSet.pressed_index == -1. This is the documented, intended behavior.

The possibility of an unset RadioSet opens up vast applications. It's a nullable enum. In my application, I want a yes/no radioSet to be unset as the default and require user action without suggesting either.

However, currently, there seems no way to programmatically unset / clear all radioButtons in a radioSet.

Curiously, I played with Textual source code and couldn't figure out an implementation. The states, RadioSet._pressed_button and RadioButton.value, seem to work beyond my comprehension.

[TomJGooding]

The RadioSet prevents a pressed button from being switched off, so trying to programmatically set pressed_button.value = False won't work:

textual/src/textual/widgets/_radio_set.py

Lines 241 to 242 in 3427dba

	# We're being clicked off, we don't want that.
	event.radio_button.value = True

I don't quite understand why you'd want to clear a RadioSet selection, but you'd need to override this behaviour.

[TomJGooding]

Here's a quick example:

from textual.app import App, ComposeResult
from textual.widgets import Button, RadioButton, RadioSet


class ExampleApp(App):
    def compose(self) -> ComposeResult:
        yield RadioSet("Yes", "No")
        yield Button("Clear selection")

    def on_button_pressed(self) -> None:
        radioset = self.query_one(RadioSet)
        pressed_button = radioset.pressed_button
        if pressed_button is not None:
            with self.prevent(RadioButton.Changed):
                pressed_button.value = False
            radioset._pressed_button = None
            self.notify("Cleared selection")
        else:
            self.notify("No option selected", severity="warning")


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

[Daniel-Chin]

I can explain the application a bit further.

I want a "the user hasn't responded" state. Example 1: The initial condition of a survey/questionnaire interface. Example 2: The user should be able to clear the radio selection as an intended "null response". This UI design is advocated by textbook and becoming mainstream in online survey platforms, and I personally find it useful as a survey taker.

In my app, I'm sidestepping the issue by providing an extra RadioButton saying "Skip", but the downsides:

• extra screenspace taken
• extra user cognitive load

From the abstract of a 2022 paper:

The results suggest that neither forcing respondents nor offering an explicit NR option is advisable, as these options strongly increase nonresponse. Rather a skipping-allowed design is a more reasonable choice.

Kmetty, Z., & Stefkovics, Á. (2022). Assessing the effect of questionnaire design on unit and item-nonresponse: Evidence from an online experiment. International Journal of Social Research Methodology, 25(5), 659-672.

[willmcgugan]

I'm open to adding an option to clear the RadioSet. Please open an issue. In the meantime, you could recompose with self.refresh(recompose=True)

[Daniel-Chin]

            with self.prevent(RadioButton.Changed):
                pressed_button.value = False
            radioset._pressed_button = None

This perfectly resolves my demand! Epic. Thank you!!

[Daniel-Chin]

I'm open to adding an option to clear the RadioSet. Please open an issue. In the meantime, you could recompose with self.refresh(recompose=True)

#6198