Struct Sensor 

pub struct Sensor<'a, Key, Message, W = Element<'a, Message>> { /* private fields */ }

A widget that can generate messages when its content pops in and out of view.

It can even notify you with anticipation at a given distance!

Implementations

impl<'a, Message, W> Sensor<'a, (), Message, W>

pub fn new(content: W) -> Self

Creates a new Sensor widget with the given content.

impl<'a, Key, Message, W> Sensor<'a, Key, Message, W>

where Key: Key,

pub fn on_show(self, on_show: impl Fn(Size) -> Message + 'a) -> Self

Sets the message to be produced when the content pops into view.

The closure will receive the [Size] of the content in that moment.

pub fn on_resize<T>(self, on_resize: impl Fn(Size) -> T + 'a) -> Self

where T: Into<Option<Message>>,

Sets the message to be produced when the content changes [Size] once its in view.

The closure will receive the new [Size] of the content.

pub fn on_hide(self, on_hide: Message) -> Self

Sets the message to be produced when the content pops out of view.

pub fn key<K>(self, key: K) -> Sensor<'a, impl Key, Message, W>

where K: Clone + PartialEq + 'static,

Sets the key of the Sensor widget, for continuity.

If the key changes, the Sensor widget will trigger again.

pub fn key_ref<K>(self, key: &'a K) -> Sensor<'a, &'a K, Message, W>

where K: ToOwned + PartialEq<K::Owned> + ?Sized, K::Owned: 'static,

Sets the key of the Sensor, for continuity; using a reference.

If the key changes, the Sensor will trigger again.

pub fn anticipate(self, distance: impl Into<Pixels>) -> Self

Sets the distance in [Pixels] to use in anticipation of the content popping into view.

This can be quite useful to lazily load items in a long scrollable behind the scenes before the user can notice it!

pub fn delay(self, delay: impl Into<Duration>) -> Self

Sets the amount of time to wait before firing an on_show or on_hide event; after the content is shown or hidden.

When combined with key, this can be useful to debounce key changes.

Trait Implementations

impl<Key, Message, W> Meta for Sensor<'_, Key, Message, W>

fn is_void(&self) -> bool

Returns whether the [Widget] is Void.

impl<Key, Message, W, Theme, Renderer> Widget<Message, Theme, Renderer> for Sensor<'_, Key, Message, W>

where Key: Key, Renderer: Renderer, W: Widget<Message, Theme, Renderer>,

fn tag(&self) -> Tag

Returns the Tag of the [Widget].

fn state(&self) -> State

Returns the State of the [Widget].

fn diff(&mut self, tree: &mut Tree)

Reconciles the [Widget] with the provided [Tree].

fn update( &mut self, tree: &mut Tree, event: &Event, layout: Layout, cursor: Cursor, renderer: &Renderer, shell: &mut Shell<'_, Message>, viewport: &Rectangle, )

Processes a runtime Event.

fn size(&self) -> Size<Length>

Returns the [Size] of the [Widget] in lengths.

fn layout(&mut self, tree: &mut Tree, renderer: &Renderer, limits: &Limits)

Lays out the [Widget].

fn draw( &self, tree: &Tree, renderer: &mut Renderer, theme: &Theme, style: &Style, layout: Layout, cursor: Cursor, viewport: &Rectangle, )

Draws the [Widget] using the associated Renderer.

fn operate( &mut self, tree: &mut Tree, layout: Layout, viewport: &Rectangle, renderer: &Renderer, operation: &mut dyn Operation, )

Applies an [Operation] to the [Widget].

fn mouse_interaction( &self, tree: &Tree, layout: Layout, cursor: Cursor, viewport: &Rectangle, renderer: &Renderer, ) -> Interaction

Returns the current [mouse::Interaction] of the [Widget].

fn overlay<'b>( &'b mut self, tree: &'b mut Tree, layout: Layout, renderer: &Renderer, viewport: &Rectangle, translation: Vector, window: Size, ) -> Vec<Element<'b, Message, Theme, Renderer>>

Returns the overlays of the [Widget].

fn _map<F, B>(self, f: F) -> Map<Self, F, Message>

where Self: Sized, F: Fn(Message) -> B,

Applies a transformation to the produced message of this [Widget], returning a [Map].

fn _boxed<'a>(self) -> Element<'a, Message, Theme, Renderer>

where Self: Sized + 'a,

Boxes this [Widget], turning it into a generic [Element].