BallisticScrollActivity class
The activity a scroll view performs after being set into motion.
For example, a BallisticScrollActivity is used when the user lifts their finger off the screen after a DragScrollActivity, to continue the scrolling motion starting from the current velocity.
BallisticScrollActivity is also used to restore a scroll view to a valid scroll offset when the geometry of the scroll view changes. In these situations, the Simulation typically starts with a zero velocity.
The scrolling will be driven by the given Simulation. If a BallisticScrollActivity is in progress when the scroll metrics change, then the activity will be replaced with a new ballistic activity starting from the current velocity (see ScrollPhysics.createBallisticSimulation). To ensure the user perceives smooth motion across such a change, the simulation should typically be the result of ScrollPhysics.createBallisticSimulation for the scroll physics of the scroll view.
See also:
- DrivenScrollActivity, which drives a scroll view through a given animation, without resetting to a ballistic simulation when scroll metrics change.
- Inheritance
-
- Object
- ScrollActivity
- BallisticScrollActivity
Constructors
- BallisticScrollActivity(ScrollActivityDelegate delegate, Simulation simulation, TickerProvider vsync, bool shouldIgnorePointer)
- Creates an activity that sets into motion a scroll view.
Properties
- delegate → ScrollActivityDelegate
-
The delegate that this activity will use to actuate the scroll view.
no setterinherited
- hashCode → int
-
The hash code for this object.
no setterinherited
- isScrolling → bool
-
Whether performing this activity constitutes scrolling.
no setteroverride
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- shouldIgnorePointer → bool
-
Whether the scroll view should ignore pointer events while performing this
activity.
final
- velocity → double
-
If applicable, the velocity at which the scroll offset is currently
independently changing (i.e. without external stimuli such as a dragging
gestures) in logical pixels per second for this activity.
no setteroverride
Methods
-
applyMoveTo(
double value) → bool - Move the position to the given location.
-
applyNewDimensions(
) → void -
Called when the scroll view that is performing this activity changes its metrics.
override
-
dispatchOverscrollNotification(
ScrollMetrics metrics, BuildContext context, double overscroll) → void -
Dispatch an OverscrollNotification with the given metrics and overscroll.
override
-
dispatchScrollEndNotification(
ScrollMetrics metrics, BuildContext context) → void -
Dispatch a ScrollEndNotification with the given metrics and overscroll.
inherited
-
dispatchScrollStartNotification(
ScrollMetrics metrics, BuildContext? context) → void -
Dispatch a ScrollStartNotification with the given metrics.
inherited
-
dispatchScrollUpdateNotification(
ScrollMetrics metrics, BuildContext context, double scrollDelta) → void -
Dispatch a ScrollUpdateNotification with the given metrics and scroll delta.
inherited
-
dispose(
) → void -
Called when the scroll view stops performing this activity.
override
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
resetActivity(
) → void -
Called by the ScrollActivityDelegate when it has changed type (for
example, when changing from an Android-style scroll position to an
iOS-style scroll position). If this activity can differ between the two
modes, then it should tell the position to restart that activity
appropriately.
override
-
toString(
) → String -
A string representation of this object.
override
-
updateDelegate(
ScrollActivityDelegate value) → void -
Updates the activity's link to the ScrollActivityDelegate.
inherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited