HoldScrollActivity class Null safety

A scroll activity that does nothing but can be released to resume normal idle behavior.

This is used while the user is touching the Scrollable but before the touch has become a Drag.

For the purposes of ScrollNotifications, this activity does not constitute scrolling, and does not prevent the user from interacting with the contents of the Scrollable (unlike when a drag has begun or there is a scroll animation underway).

Implemented types


HoldScrollActivity({required ScrollActivityDelegate delegate, VoidCallback? onHoldCanceled})
Creates a scroll activity that does nothing.


delegate ScrollActivityDelegate
The delegate that this activity will use to actuate the scroll view.
read-only, inherited
hashCode int
The hash code for this object.
read-only, inherited
isScrolling bool
Whether performing this activity constitutes scrolling.
read-only, override
onHoldCanceled VoidCallback?
Called when dispose is called.
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited
shouldIgnorePointer bool
Whether the scroll view should ignore pointer events while performing this activity.
read-only, override
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.
read-only, override


applyNewDimensions() → void
Called when the scroll view that is performing this activity changes its metrics.
cancel() → void
Release the Scrollable, potentially letting it go ballistic if necessary.
dispatchOverscrollNotification(ScrollMetrics metrics, BuildContext context, double overscroll) → void
Dispatch an OverscrollNotification with the given metrics and overscroll.
dispatchScrollEndNotification(ScrollMetrics metrics, BuildContext context) → void
Dispatch a ScrollEndNotification with the given metrics and overscroll.
dispatchScrollStartNotification(ScrollMetrics metrics, BuildContext? context) → void
Dispatch a ScrollStartNotification with the given metrics.
dispatchScrollUpdateNotification(ScrollMetrics metrics, BuildContext context, double scrollDelta) → void
Dispatch a ScrollUpdateNotification with the given metrics and scroll delta.
dispose() → void
Called when the scroll view stops performing this activity.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
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.
toString() String
A string representation of this object.
updateDelegate(ScrollActivityDelegate value) → void
Updates the activity's link to the ScrollActivityDelegate.


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