Struct AlwaysScrollable 

pub struct AlwaysScrollable { /* private fields */ }

Flutter’s AlwaysScrollableScrollPhysics: accept a drag whether or not there is anything to scroll, and defer everything else to the chained parent.

Composed rather than used alone — AlwaysScrollable::new().chain(Clamping::new()) is a clamping surface that a pull-to-refresh gesture can still reach on a short page.

Implementations

impl AlwaysScrollable

pub fn new() -> AlwaysScrollable

A standalone always-scrollable physics (no chained parent).

pub fn chain(self, parent: impl ScrollPhysics + 'static) -> AlwaysScrollable

Chain parent behind this physics, the module-wide composition convention (ScrollPhysics’ Chaining).

Trait Implementations

impl Debug for AlwaysScrollable

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

Formats the value using the given formatter.

impl Default for AlwaysScrollable

fn default() -> AlwaysScrollable

Returns the “default value” for a type.

impl ScrollPhysics for AlwaysScrollable

fn should_accept_user_offset(&self, _metrics: &ScrollMetrics) -> bool

The one thing this physics has an opinion about.

fn parent(&self) -> Option<&dyn ScrollPhysics>

The chained parent physics, if this one was built via chain(...). None for a physics built standalone (the chain’s root).

fn apply_physics_to_user_offset( &self, metrics: &ScrollMetrics, offset: f64, ) -> f64

Map a raw user drag delta (finger px, signed in the content’s own direction) to the delta actually applied to the position. Must not alter the in-bounds portion of a drag — only a physics with an out-of-bounds opinion (e.g. added resistance) touches this.

fn apply_boundary_conditions(&self, metrics: &ScrollMetrics, value: f64) -> f64

Given a proposed new pixels value, return the portion the position must not absorb — the boundary-rejected excess. 0.0 means the proposal is fully allowed (a bouncing physics past an edge); the full proposed − clamped distance means none of it is (a clamping physics).

fn create_ballistic_simulation( &self, metrics: &ScrollMetrics, velocity: f64, ) -> Option<Box<dyn Simulation>>

Build the ballistic motion to run after a gesture releases with velocity (px/s, signed like ScrollMetrics::pixels). None means no animation — the consuming widget falls back to its own legacy path/rest handling.

fn carried_momentum(&self, existing_velocity: f64) -> f64

Momentum (px/s) to add onto a new fling’s initial velocity when motion is already live (a re-fling mid-animation carries some of the old velocity forward rather than starting cold).

fn min_fling_velocity(&self) -> f64

The minimum release speed that starts a fling.

fn max_fling_velocity(&self) -> f64

The fastest fling speed this physics honors.

fn tolerance_for(&self, metrics: &ScrollMetrics) -> Tolerance

The velocity/distance tolerance a ballistic simulation settles within.

fn spring(&self) -> SpringDescription

The spring a bounce-back/snap simulation is built from.