Struct Switch 

pub struct Switch {
    pub on: bool,
    /* private fields */
}

A toggle switch — the reference “premium widget” (Q0 quality-bar exemplar).

Ships beautiful with zero config and stays fully overridable. It layers every state a real toggle needs on top of one animated value:

• Motion — the thumb slides (theme-eased) between off/on; because the thumb radius is derived from that same 0→1 position, it also grows as it settles on, Material-3 style, for free (one node scalar, see animate_to).
• States — idle · hover · pressed (thumb stretches) · focus-visible (ring + state-layer halo) · disabled (dimmed, inert) · on/off.
• Elevation — the thumb casts a soft drop shadow so it reads as a physical knob above the track.
• Theming — track/thumb/halo all come from theme tokens (primary, surface_variant, on_primary, outline, shadow); light+dark adapt automatically. Any of them can be overridden per-instance.
• A11y — Role::Switch with an on/off value, a Tab-focusable node, and an optional label for screen readers.
• Interactive-by-identity — always owns its hit region, wired or not, so a tap can never fall through to a pannable surface behind it.

Fields

on: bool

The current value.

Implementations

impl Switch

pub fn new(on: bool) -> Self

pub fn on_change(self, f: impl Fn(bool) + Send + Sync + 'static) -> Self

Called with the NEW value when the switch is toggled (D094).

pub fn disabled(self) -> Self

Non-interactive, dimmed, and inert (still absorbs the tap so nothing behind it reacts).

pub fn disabled_if(self, c: bool) -> Self

pub fn label(self, l: impl Into<String>) -> Self

Accessibility label announced by screen readers alongside the on/off value.

pub fn size(self, width: f32, height: f32) -> Self

Override the track size (default 44×24). Proportions stay tasteful at any reasonable size.

pub fn on_color(self, c: Color) -> Self

Override the on-track color (default: theme primary).

pub fn off_color(self, c: Color) -> Self

Override the off-track color (default: theme surface_variant).

pub fn thumb_color(self, c: Color) -> Self

Override the thumb color (default: theme on_primary on / outline off).

Trait Implementations

impl Widget for Switch

fn layout(&self, ctx: &LayoutCtx<'_>) -> Size

Measure under ctx.constraints and return a size within them.

fn paint(&self, ctx: &mut PaintCtx<'_>)

Record draw commands for ctx.rect.

fn children(&self) -> Children<'_>

Declare this widget’s children. Drives every default below.

fn flex_factor(&self) -> f32

Flex weight inside Row/Column. Wrappers are transparent by default.

fn into_element(self) -> Element

where Self: Sized + 'static,

Wrap this widget in an Element so it can be returned from Component::build().