FixedOverscrollBouncingScrollPhysics class

This is the behavior typically seen on iOS. drag loadmore item, overscroll will increase viewport pixels and maxScrollExtent at that moment and jump into new pixels which is much bigger we should correct pixels in BouncingScrollPhysics.adjustPositionForNewDimensions

old rule if (oldPosition.pixels > oldPosition.maxScrollExtent) { final double oldDelta = oldPosition.pixels - oldPosition.maxScrollExtent; return newPosition.maxScrollExtent + oldDelta; }

new rule if (oldPosition.pixels > oldPosition.maxScrollExtent) { final double oldDelta = oldPosition.pixels - oldPosition.maxScrollExtent; return newPosition.pixels + oldDelta; }

see RangeMaintainingScrollPhysics.adjustPositionForNewDimensions



FixedOverscrollBouncingScrollPhysics({ScrollPhysics? parent})


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
decelerationRate ScrollDecelerationRate
Used to determine parameters for friction simulations.
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.
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


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.
applyBoundaryConditions(ScrollMetrics position, double value) double
Determines the overscroll by applying the boundary conditions.
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.
applyTo(ScrollPhysics? ancestor) FixedOverscrollBouncingScrollPhysics
Combines this ScrollPhysics instance with the given physics.
buildParent(ScrollPhysics? ancestor) ScrollPhysics?
If parent is null then return ancestor, otherwise recursively build a ScrollPhysics that has ancestor as its parent.
carriedMomentum(double existingVelocity) double
Momentum build-up function that mimics iOS's scroll speed increase with repeated flings.
createBallisticSimulation(ScrollMetrics position, double velocity) Simulation?
Returns a simulation for ballistic scrolling starting from the given position with the given velocity.
frictionFactor(double overscrollFraction) double
The multiple applied to overscroll to make it appear that scrolling past the edge of the scrollable contents is harder than scrolling the list. This is done by reducing the ratio of the scroll effect output vs the scroll gesture input.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
recommendDeferredLoading(double velocity, ScrollMetrics metrics, BuildContext context) bool
Provides a heuristic to determine if expensive frame-bound tasks should be deferred.
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.
toleranceFor(ScrollMetrics metrics) Tolerance
The tolerance to use for ballistic simulations.
toString() String
A string representation of this object.


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