[feature request] option to prevent "no selection" (aka radio button set)

[artificiel]

it would be great to be able to enforce at least one selection: in conjunction with disableMultipleSelection(), it would behave like a radio button, where one of the options is always required. perhaps some call like disallowEmptySelectedValue().

thought it would be a simple implementation but (as far as I understand) the ofxDropdownOption process their own mouse clicks and toggle themselves, without being aware if a rule would prevent themselves to toggle off?

would the design be to propagate a new _bDisallowSelfTurningOff bool into the Options? there seems to be the idea around _bSelectOnMouseRelease but it's not clear what happens if the flag is set before children are populated?

[roymacdonald]

Hi @artificiel !
Thanks for the feedback.
It actually makes a lot of sense.
I am not sure about the implementation as I have not checked the code of this addon for quite a long time. I will check and let you know.
But if you have something working please make a PR.

On the other hand, in the cases where I want it to always be just a single selection, where it is always just one selected, I prefer using enums and an int parameter. This will always be just one of the options and at the same time is allows for cleaner code; it becomes something like a state machine, where you only need to check for a particular state rather than keeping track of multiple booleans and their possible combinations.

[a-voronov]

@roymacdonald it's been a while, but could you please explain how you're using enums and int parameter? I'm trying to use ofxIntDropdown with ofParameter<int> but it has the same behavior as with string parameter, or were you talking about something completely different?

[roymacdonald]

@a-voronov what do you mean that using int or strinng are doing the same? The idea is that when you select something in the dropdown the ofparameter associated to it will change to the selected value. So, if you use int it would be the index of the options you added or if it is a string it is either the same string shown in the dropdown or another one associated to it when you added the option. So the behaviour is essentially the same, just different types you use as the index.
What are you trying to achieve?

[a-voronov]

@roymacdonald ah maybe I misunderstood you earlier, thanks! I'm trying to achieve the behavior where there's always one item selected at a time, i.e. like a radio group. However either I'm using ofParameter with int or string, the deselection of the selected item is still possible

[roymacdonald]

@a-voronov I see. right now I don't have that feature implemented. I can't provide a fix right now, but you are very welcome to make a PR.