For the CSS side, the div containing the switcher has now an additional class when disabled. So it should be possible to target the disabled switchers with div.switcher.disabled. Hope that helps.

Readonly and disabled attributes are not the same. Values of disabled inputs are not submitted to the server. When readonly is used, selected radio should not be disabled.

The thing is, there is no readonly attribute for radio elements. See https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/readonly.
I've used the same behavior we already use in J3 and in the radio buttons.

We can emulate readonly behavior by disabling all inputs except currently selected. Not sure how accessible that is though. @brianteeman any thoughts?

@SharkyKZ Why do you want to emulate readonly? The readonly attribute doesn't make sense for radios, that's why it doesn't exist. There is no point in emulating it.

Treating readonly and disabled the same is no good. We need to have the selected value submitted when readonly is used. It's not a matter of whether HTML element supports it or not, it's about how we implement the functionality in our fields.

can someone tell me the use case for this

Not allowing to change the value after the form was submitted for the first time. Or having a field disabled until another field has been filled in.

As said, readonly doesn't exist for that type of input.
I just added it for convenience and since it was already in J3 and in the button layout. The readonly and disabled attribute set in the XML will both result in a disabled radio/switcher/button input.

The dev using a readonly/disabled element has to take care of this on PHP side. You couldn't trust the submitted value anyway as the user could remove the disabled/readonly attribute in the browser.

I have tested this item ✅ successfully on 87f2daa

I think this implementation is user-friendly. The normal user does not know that there is no readonly for the radio type. He doesn't even know that the switcher is a radio input. At readonly, he expects exactly what bakual has programmed technically correctly here.

@brianteeman Just as for the button, there are also use cases for the switch. You want to show that it is an option, but that it is deactivated with the current settings.

It only bothered me that the appearance does not change. It looks like a mistake. That's why I added a PR here.
@Bakual If you like, please merge or add to your code.

For my test I added

disabled = "1"

to a switch in the file
joomla-cms4/administrator/components/com_templates/forms/source.xml

I tested also with

readonly = "true"
disabled = "true"
readonly = "1"

I tested also with the from me applied change. It looks like this:

If you like, please merge or add to your code.

Merged. Thanks for the help!

I have tested this item ✅ successfully on d39e43e

RTC

Setting back to Pending as there has only been one successful test.

Setting back to Pending as there has only been one successful test.

@jwaisner It's two tests. One from Quy and one from Astridx

RTC

Merged thanks @Bakual & testers ?