Struct WidgetStateProperty 

pub struct WidgetStateProperty<T> { /* private fields */ }

A value chosen by the states a widget is in (widget_state.dart:821).

Entries are tried in order and the first match wins, which is the reference’s WidgetStateMapper (widget_state.dart:1009) and the reason order is worth thinking about: put the narrow cases first.

use frus_core::Color;
use frus_widgets::{WidgetState, WidgetStateProperty, WidgetStates};

let ink = WidgetStateProperty::new()
    .when(WidgetState::Pressed, Color::rgb8(200, 0, 0))
    .when(WidgetState::Hovered, Color::rgb8(240, 120, 120))
    .otherwise(Color::TRANSPARENT);

// Held *and* hovered, as a pressed widget always is: the narrower entry answers.
let held = WidgetState::Pressed | WidgetState::Hovered;
assert_eq!(ink.resolve(held), Some(&Color::rgb8(200, 0, 0)));
assert_eq!(ink.resolve(WidgetStates::EMPTY), Some(&Color::TRANSPARENT));

A property built from closures — the reference’s resolveWith — is deliberately not offered. A map is Clone, Debug and comparable, which is what a widget tree that is rebuilt and diffed every frame needs; a boxed closure is none of the three, and the reference itself documents the map as the form to reach for.

Implementations

impl<T> WidgetStateProperty<T>

pub fn new() -> Self

A property that answers nothing yet.

pub fn all(value: T) -> Self

The same value whatever the widget is doing — the reference’s WidgetStatePropertyAll (widget_state.dart:1077), and what a caller who has one colour and an API that wants a property reaches for.

pub fn when(self, filter: impl Into<StateFilter>, value: T) -> Self

The value to use when filter is satisfied, tried after everything already added and before everything added later.

pub fn otherwise(self, value: T) -> Self

The value to use when nothing above matched. Anything added after it is unreachable, Any being satisfied by every set.

pub fn resolve(&self, states: WidgetStates) -> Option<&T>

The first value whose filter these states satisfy, or None when none does — which means say nothing, and leaves the widget or the theme to answer, exactly as the reference’s nullable properties do.

pub fn is_empty(&self) -> bool

Has anything been said at all?

Trait Implementations

impl<T: Clone> Clone for WidgetStateProperty<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for WidgetStateProperty<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> Default for WidgetStateProperty<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T: PartialEq> PartialEq for WidgetStateProperty<T>

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl<T: PartialEq> StructuralPartialEq for WidgetStateProperty<T>