FixedExtentScrollPhysics class

A snapping physics that always lands directly on items instead of anywhere within the scroll extent.

Behaves similarly to a slot machine wheel except the ballistics simulation never overshoots and rolls back within a single item if it's to settle on that item.

Must be used with a scrollable that uses a FixedExtentScrollController.

Defers back to the parent beyond the scroll extents.

Inheritance

Constructors

FixedExtentScrollPhysics({ScrollPhysics? parent})
Creates a scroll physics that always lands on items.
const

Properties

allowImplicitScrolling → bool
Whether a viewport is allowed to change its scroll position implicitly in response to a call to RenderObject.showOnScreen.
no setterinherited
allowUserScrolling → bool
Whether a viewport is allowed to change the scroll position as the result of user input.
no setterinherited
dragStartDistanceMotionThreshold → double?
The minimum amount of pixel distance drags must move by to start motion the first time or after each time the drag motion stopped.
no setterinherited
hashCode → int
The hash code for this object.
no setterinherited
maxFlingVelocity → double
Scroll fling velocity magnitudes will be clamped to this value.
no setterinherited
minFlingDistance → double
The minimum distance an input pointer drag must have moved to be considered a scroll fling gesture.
no setterinherited
minFlingVelocity → double
The minimum velocity for an input pointer drag to be considered a scroll fling.
no setterinherited
parent → ScrollPhysics?
If non-null, determines the default behavior for each method.
finalinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
spring → SpringDescription
The spring to use for ballistic simulations.
no setterinherited
tolerance → Tolerance
Deprecated. Call toleranceFor instead.
no setterinherited

Methods

adjustPositionForNewDimensions({required ScrollMetrics oldPosition, required ScrollMetrics newPosition, required bool isScrolling, required double velocity}) → double
Describes what the scroll position should be given new viewport dimensions.
inherited
applyBoundaryConditions(ScrollMetrics position, double value) → double
Determines the overscroll by applying the boundary conditions.
inherited
applyPhysicsToUserOffset(ScrollMetrics position, double offset) → double
Used by DragScrollActivity and other user-driven activities to convert an offset in logical pixels as provided by the DragUpdateDetails into a delta to apply (subtract from the current position) using ScrollActivityDelegate.setPixels.
inherited
applyTo(ScrollPhysics? ancestor) → FixedExtentScrollPhysics
Combines this ScrollPhysics instance with the given physics.
override
buildParent(ScrollPhysics? ancestor) → ScrollPhysics?
If parent is null then return ancestor, otherwise recursively build a ScrollPhysics that has ancestor as its parent.
inherited
carriedMomentum(double existingVelocity) → double
Returns the velocity carried on repeated flings.
inherited
createBallisticSimulation(ScrollMetrics position, double velocity) → Simulation?
Returns a simulation for ballistic scrolling starting from the given position with the given velocity.
override
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
recommendDeferredLoading(double velocity, ScrollMetrics metrics, BuildContext context) → bool
Provides a heuristic to determine if expensive frame-bound tasks should be deferred.
inherited
shouldAcceptUserOffset(ScrollMetrics position) → bool
Whether the scrollable should let the user adjust the scroll offset, for example by dragging. If allowUserScrolling is false, the scrollable will never allow user input to change the scroll position.
inherited
toleranceFor(ScrollMetrics metrics) → Tolerance
The tolerance to use for ballistic simulations.
inherited
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited