PixelSnapScrollPosition class

ScrollPosition subclass that snaps to nearest physical pixel.

Inheritance

Constructors

PixelSnapScrollPosition({required ScrollPhysics physics, required ScrollContext context, bool keepScrollOffset = true, double? initialPixels = 0.0, ScrollPosition? oldPosition, String? debugLabel})

Properties

activity → ScrollActivity?
The currently operative ScrollActivity.
no setterinherited
allowImplicitScrolling → bool
Whether a viewport is allowed to change pixels implicitly to respond to a call to RenderObject.showOnScreen.
no setterinherited
atEdge → bool
Whether the pixels value is exactly at the minScrollExtent or the maxScrollExtent.
no setterinherited
axis → Axis
The axis in which the scroll view scrolls.
no setterinherited
axisDirection → AxisDirection
The direction in which the scroll view scrolls.
no setterinherited
context → ScrollContext
Where the scrolling is taking place.
finalinherited
debugLabel → String?
A label that is used in the toString output.
finalinherited
devicePixelRatio → double
The FlutterView.devicePixelRatio of the view that the Scrollable associated with this metrics object is drawn into.
no setterinherited
extentAfter → double
The quantity of content conceptually "below" the viewport in the scrollable. This is the content below the content described by extentInside.
no setterinherited
extentBefore → double
The quantity of content conceptually "above" the viewport in the scrollable. This is the content above the content described by extentInside.
no setterinherited
extentInside → double
The quantity of content conceptually "inside" the viewport in the scrollable (including empty space if the total amount of content is less than the viewportDimension).
no setterinherited
extentTotal → double
The total quantity of content available.
no setterinherited
hasContentDimensions → bool
Whether the minScrollExtent and the maxScrollExtent properties are available.
no setterinherited
hashCode → int
The hash code for this object.
no setterinherited
hasListeners → bool
Whether any listeners are currently registered.
no setterinherited
hasPixels → bool
Whether the pixels property is available.
no setterinherited
hasViewportDimension → bool
Whether the viewportDimension property is available.
no setterinherited
haveDimensions → bool
Whether viewportDimension, minScrollExtent, maxScrollExtent, outOfRange, and atEdge are available.
no setterinherited
isScrollingNotifier → ValueNotifier<bool>
This notifier's value is true if a scroll is underway and false if the scroll position is idle.
finalinherited
keepScrollOffset → bool
Save the current scroll offset with PageStorage and restore it if this scroll position's scrollable is recreated.
finalinherited
maxScrollExtent → double
The maximum in-range value for pixels.
no setterinherited
minScrollExtent → double
The minimum in-range value for pixels.
no setterinherited
outOfRange → bool
Whether the pixels value is outside the minScrollExtent and maxScrollExtent.
no setterinherited
physics → ScrollPhysics
How the scroll position should respond to user input.
finalinherited
pixels → double
The number of pixels to offset the children in the opposite of the axis direction.
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
shouldIgnorePointer → bool
Whether scrollables should absorb pointer events at this position.
no setterinherited
userScrollDirection → ScrollDirection
The direction in which the user is trying to change pixels, relative to the viewport's RenderViewportBase.axisDirection.
no setterinherited
viewportDimension → double
The extent of the viewport along the axisDirection.
no setterinherited

Methods

absorb(ScrollPosition other) → void
Take any current applicable state from the given ScrollPosition.
inherited
addListener(VoidCallback listener) → void
Register a closure to be called when the object changes.
inherited
animateTo(double to, {required Duration duration, required Curve curve}) → Future<void>
Animates the position from its current value to the given value.
inherited
applyBoundaryConditions(double value) → double
Returns the overscroll by applying the boundary conditions.
inherited
applyContentDimensions(double minScrollExtent, double maxScrollExtent) → bool
Called when the viewport's content extents are established.
inherited
applyNewDimensions() → void
Notifies the activity that the dimensions of the underlying viewport or contents have changed.
inherited
applyUserOffset(double delta) → void
Updates the scroll position by the given amount.
inherited
applyViewportDimension(double viewportDimension) → bool
Called when the viewport's extents are established.
inherited
beginActivity(ScrollActivity? newActivity) → void
Change the current activity, disposing of the old one and sending scroll notifications as necessary.
inherited
copyWith({double? minScrollExtent, double? maxScrollExtent, double? pixels, double? viewportDimension, AxisDirection? axisDirection, double? devicePixelRatio}) → ScrollMetrics
Creates a ScrollMetrics that has the same properties as this object.
inherited
correctBy(double correction) → void
Apply a layout-time correction to the scroll offset.
override
correctForNewDimensions(ScrollMetrics oldPosition, ScrollMetrics newPosition) → bool
Verifies that the new content and viewport dimensions are acceptable.
inherited
correctPixels(double value) → void
Change the value of pixels to the new value, without notifying any customers.
override
debugFillDescription(List<String> description) → void
Add additional information to the given description for use by toString.
inherited
didEndScroll() → void
Called by beginActivity to report when an activity has ended.
inherited
didOverscrollBy(double value) → void
Called by setPixels to report overscroll when an attempt is made to change the pixels position. Overscroll is the amount of change that was not applied to the pixels value.
inherited
didStartScroll() → void
Called by beginActivity to report when an activity has started.
inherited
didUpdateScrollDirection(ScrollDirection direction) → void
Dispatches a notification that the userScrollDirection has changed.
inherited
didUpdateScrollMetrics() → void
Dispatches a notification that the ScrollMetrics have changed.
inherited
didUpdateScrollPositionBy(double delta) → void
Called by setPixels to report a change to the pixels position.
inherited
dispose() → void
Discards any resources used by the object. After this is called, the object is not in a usable state and should be discarded (calls to addListener will throw after the object is disposed).
inherited
drag(DragStartDetails details, VoidCallback dragCancelCallback) → Drag
Start a drag activity corresponding to the given DragStartDetails.
inherited
ensureVisible(RenderObject object, {double alignment = 0.0, Duration duration = Duration.zero, Curve curve = Curves.ease, ScrollPositionAlignmentPolicy alignmentPolicy = ScrollPositionAlignmentPolicy.explicit, RenderObject? targetRenderObject}) → Future<void>
Animates the position such that the given object is as visible as possible by just scrolling this position.
inherited
forcePixels(double value) → void
Change the value of pixels to the new value, and notify any customers, but without honoring normal conventions for changing the scroll offset.
override
goBallistic(double velocity) → void
Start a physics-driven simulation that settles the pixels position, starting at a particular velocity.
inherited
goIdle() → void
Terminate the current activity and start an idle activity.
inherited
hold(VoidCallback holdCancelCallback) → ScrollHoldController
Stop the current activity and start a HoldScrollActivity.
inherited
jumpTo(double value) → void
Jumps the scroll position from its current value to the given value, without animation, and without checking if the new value is in range.
inherited
jumpToWithoutSettling(double value) → void
Deprecated. Use jumpTo or a custom ScrollPosition instead.
inherited
moveTo(double to, {Duration? duration, Curve? curve, bool? clamp = true}) → Future<void>
Calls jumpTo if duration is null or Duration.zero, otherwise animateTo is called.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
notifyListeners() → void
Call all the registered listeners.
inherited
pointerScroll(double delta) → void
Changes the scrolling position based on a pointer signal from current value to delta without animation and without checking if new value is in range, taking min/max scroll extent into account.
inherited
recommendDeferredLoading(BuildContext context) → bool
Provides a heuristic to determine if expensive frame-bound tasks should be deferred.
inherited
removeListener(VoidCallback listener) → void
Remove a previously registered closure from the list of closures that are notified when the object changes.
inherited
restoreOffset(double offset, {bool initialRestore = false}) → void
Called by context to restore the scroll offset to the provided value.
inherited
restoreScrollOffset() → void
Called whenever the ScrollPosition is created, to restore the scroll offset if possible.
inherited
saveOffset() → void
Called whenever scrolling ends, to persist the current scroll offset for state restoration purposes.
inherited
saveScrollOffset() → void
Called whenever scrolling ends, to store the current scroll offset in a storage mechanism with a lifetime that matches the app's lifetime.
inherited
setPixels(double newPixels) → double
Update the scroll position (pixels) to a given pixel value.
override
toString() → String
A string representation of this object.
inherited
updateUserScrollDirection(ScrollDirection value) → void
Set userScrollDirection to the given value.
inherited

Operators

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