IOSScrollViewFlingVelocityTracker class

A VelocityTracker subclass that provides a close approximation of iOS scroll view's velocity estimation strategy.

The estimated velocity reported by this class is a close approximation of the velocity an iOS scroll view would report with the same PointerMoveEvents, when the touch that initiates a fling is released.

This class differs from the VelocityTracker class in that it uses weighted average of the latest few velocity samples of the tracked pointer, instead of doing a linear regression on a relatively large amount of data points, to estimate the velocity of the tracked pointer. Adding data points and estimating the velocity are both cheap.

To obtain a velocity, call getVelocity or getVelocityEstimate. The estimated velocity is typically used as the initial flinging velocity of a Scrollable, when its drag gesture ends.

See also:



IOSScrollViewFlingVelocityTracker(PointerDeviceKind kind)
Create a new IOSScrollViewFlingVelocityTracker.


hashCode int
The hash code for this object.
no setterinherited
kind PointerDeviceKind
The kind of pointer this tracker is for.
runtimeType Type
A representation of the runtime type of the object.
no setterinherited


addPosition(Duration time, Offset position) → void
Adds a position as the given time to the tracker.
getVelocity() Velocity
Computes the velocity of the pointer at the time of the last provided data point.
getVelocityEstimate() VelocityEstimate
Returns an estimate of the velocity of the object being tracked by the tracker given the current information available to the tracker.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
toString() String
A string representation of this object.


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