RFC: new property in ToggleGroup

[Kevin Rushforth]

On 1/20/2023 2:57 PM, Andy Goryachev wrote:
>
> I just want to add one thing - the initial state of RadioMenuItems 
> added to a menu is unselected, even if they belong to a ToggleGroup.
>
> One can say that having all unselected radio buttons in a toggle group 
> makes no sense, or perhaps it depends on the application requirements 
> - though I cannot find an example where it might be needed.
>

Yes, it's initially unselected unless the app makes an explicit 
selection. HTML radio buttons work the same way [1]. Some apps use that 
to indicate that nothing was selected, but then once you select it there 
will always be something selected.


> So either we allow two different policies by adding a property to the 
> ToggleGroup, or we proclaim that adding a radio button to a toggle 
> group must have a side effect of one (first) button to be 
> automatically selected, otherwise the whole group is in inconsistent 
> state (or the app developer must write some code to select one).
>

I wouldn't want to change the default behavior, since I can imagine some 
apps relying on being able to tell if the user has ever selected any of 
the choices.

Having two properties would be one solution, presuming we think that we 
need to provide a way for the app to indicate that it wants us to 
enforce the invariant of ensuring that the app can't ever get the 
control in a state where nothing is selected. Although, since it would 
be an opt-in, the app could just as easily set the default itself as 
opposed to setting this new  property.

-- Kevin

[1] 
https://www.w3schools.com/tags/tryit.asp?filename=tryhtml5_input_type_radio

> -andy
>
> *From: *openjfx-dev <openjfx-dev-retn at openjdk.org> on behalf of Kevin 
> Rushforth <kevin.rushforth at oracle.com>
> *Date: *Friday, 2023/01/20 at 12:27
> *To: *openjfx-dev at openjdk.org <openjfx-dev at openjdk.org>
> *Subject: *Re: RFC: new property in ToggleGroup
>
> How common a UI feature is being able to deselect the selected item in 
> a ToggleGroup via the UI such that no item is selected? I don't 
> normally see that in various apps or toolkits that I am familiar with. 
> What I do see is that either a default item is selected or no item is 
> selected initially (which is the one and only time that there will be 
> no item selected), but in both case, once you make a selection, there 
> is no way via the UI to deselect the current item. Absent a compelling 
> need, I think the current behavior (once the fix for JDK-8237505 is 
> integrated) is sufficient.
>
> What do other developers think?
>
> -- Kevin
>
> On 1/20/2023 11:31 AM, Andy Goryachev wrote:
>
>     Dear colleagues:
>
>     In the context of a recent PR
>
>     https://bugs.openjdk.org/browse/JDK-8237505
>
>     https://github.com/openjdk/jfx/pull/1002
>
>     https://stackoverflow.com/questions/57911107/javafx-togglegroup-not-functioning-properly-with-accelerators-radiomenuitem
>
>     where a number of RadioMenuItems belonging to a toggle group are
>     added to the menu, we might want to add a new property to the
>     ToggleGroup which controls whether all items in a group can be
>     deselected.
>
>     If this property is set, a selected radio menu item can be
>     deselected via either keyboard accelerator or a mouse click.  If
>     not, then not only this operation cannot be performed, but also
>     the first item added to said ToggleGroup gets automatically selected.
>
>     This should allow for more flexibility in creating menus with
>     RadioMenuItems, but eliminate some boilerplate code required in
>     such cases.
>
>     The new logic would also affect any Toggle, such as ToggleButton.
>
>     What do you think?  Thank you.
>
>     -andy
>
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