How to specify a constraint for a bunch of CheckBox that at least a CheckBox should be checked?

[evan0greenup]

When there is a bunch of CheckBox (Just mentally selected, no extra components are involved), If I want to add a logical constraint to them which at any moment, at least a CheckBox should be checked.

What is the most efficient way to achieve that?

[ogoffart]

One day we'll have a RadioButton (#2732)

In the mean time, it has to be done manually.
For example like this:

slint/examples/fancy_demo/main.slint

Lines 388 to 395 in c170c51

	Row {
	Text { text: "RadioButton:"; }
	HorizontalBox {
	alignment: start;
	r1 := RadioButton { text: "First"; clicked => { root.unsel(); r1.checked = true; } }
	r2 := RadioButton { text: "Second"; clicked => { root.unsel(); r2.checked = true; } }
	r3 := RadioButton { text: "Third"; clicked => { root.unsel(); r3.checked = true; } }
	}

In that example, the RadioButton is just like a CheckBox, but it uses "clicked" instead of "toggled"

And also the unsel funciton is

slint/examples/fancy_demo/main.slint

Line 363 in c170c51

function unsel() { r1.checked = false; r2.checked = false; r3.checked = false; }