ScrollPositionWithSingleContext class

A scroll position that manages scroll activities for a single ScrollContext.

This class is a concrete subclass of ScrollPosition logic that handles a single ScrollContext, such as a Scrollable. An instance of this class manages ScrollActivity instances, which change what content is visible in the Scrollable's Viewport.

Constructors

ScrollPositionWithSingleContext({@required ScrollPhysics physics, @required ScrollContext context, double initialPixels: 0.0, bool keepScrollOffset: true, ScrollPosition oldPosition, String debugLabel }): Create a ScrollPosition object that manages its behavior using ScrollActivity objects. [...]

Properties

axisDirection → AxisDirection: The direction in which the scroll view scrolls.
read-only, override
userScrollDirection → ScrollDirection: The direction in which the user is trying to change pixels, relative to the viewport's RenderViewport.axisDirection. [...]
read-only, override
activity → ScrollActivity: The currently operative ScrollActivity. [...]
@protected, read-only, inherited
allowImplicitScrolling → bool: Whether a viewport is allowed to change pixels implicitly to respond to a call to RenderObject.showOnScreen. [...]
read-only, inherited
atEdge → bool: Whether the pixels value is exactly at the minScrollExtent or the maxScrollExtent.
read-only, inherited
axis → Axis: The axis in which the scroll view scrolls.
read-only, inherited
context → ScrollContext: Where the scrolling is taking place. [...]
final, inherited
debugLabel → String: A label that is used in the toString output. [...]
final, inherited
extentAfter → double: The quantity of content conceptually "below" the currently visible content of the viewport in the scrollable. This is the content below the content described by extentInside.
read-only, inherited
extentBefore → double: The quantity of content conceptually "above" the currently visible content of the viewport in the scrollable. This is the content above the content described by extentInside.
read-only, inherited
extentInside → double: The quantity of visible content. [...]
read-only, inherited
hashCode → int: The hash code for this object. [...]
read-only, inherited
hasListeners → bool: Whether any listeners are currently registered. [...]
@protected, read-only, inherited
haveDimensions → bool: Whether viewportDimension, minScrollExtent, maxScrollExtent, outOfRange, and atEdge are available. [...]
read-only, inherited
isScrollingNotifier → ValueNotifier<bool>: This notifier's value is true if a scroll is underway and false if the scroll position is idle. [...]
final, inherited
keepScrollOffset → bool: Save the current scroll offset with PageStorage and restore it if this scroll position's scrollable is recreated. [...]
final, inherited
maxScrollExtent → double: The maximum in-range value for pixels. [...]
read-only, inherited
minScrollExtent → double: The minimum in-range value for pixels. [...]
read-only, inherited
outOfRange → bool: Whether the pixels value is outside the minScrollExtent and maxScrollExtent.
read-only, inherited
physics → ScrollPhysics: How the scroll position should respond to user input. [...]
final, inherited
pixels → double: The number of pixels to offset the children in the opposite of the axis direction. [...]
read-only, inherited
runtimeType → Type: A representation of the runtime type of the object.
read-only, inherited
viewportDimension → double: The extent of the viewport along the axisDirection.
read-only, inherited

Methods

absorb(ScrollPosition other) → void: Take any current applicable state from the given ScrollPosition. [...]
override
animateTo(double to, { Duration duration, Curve curve }) → Future<void>: Animates the position from its current value to the given value. [...]
override
applyNewDimensions() → void: Notifies the activity that the dimensions of the underlying viewport or contents have changed. [...]
override
applyUserOffset(double delta) → void: Updates the scroll position by the given amount. [...]
override
beginActivity(ScrollActivity newActivity) → void: Change the current activity, disposing of the old one and sending scroll notifications as necessary. [...]
override
debugFillDescription(List<String> description) → void: Add additional information to the given description for use by toString. [...]
override
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 and removeListener will throw after the object is disposed). [...]
override
drag(DragStartDetails details, VoidCallback dragCancelCallback) → Drag: Start a drag activity corresponding to the given DragStartDetails. [...]
override
goBallistic(double velocity) → void: Start a physics-driven simulation that settles the pixels position, starting at a particular velocity. [...]
override
goIdle() → void: Terminate the current activity and start an idle activity.
override
hold(VoidCallback holdCancelCallback) → ScrollHoldController: Stop the current activity and start a HoldScrollActivity.
override
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. [...]
override
jumpToWithoutSettling(double value) → void: Deprecated. Use jumpTo or a custom ScrollPosition instead.
@Deprecated('This will lead to bugs.'), override
setPixels(double newPixels) → double: Update the scroll position (pixels) to a given pixel value. [...]
override
updateUserScrollDirection(ScrollDirection value) → void: Set userScrollDirection to the given value. [...]
@protected
addListener(VoidCallback listener) → void: Register a closure to be called when the object changes. [...]
inherited
applyBoundaryConditions(double value) → double: Returns the overscroll by applying the boundary conditions. [...]
@protected, inherited
applyContentDimensions(double minScrollExtent, double maxScrollExtent) → bool: Called when the viewport's content extents are established. [...]
inherited
applyViewportDimension(double viewportDimension) → bool: Called when the viewport's extents are established. [...]
inherited
copyWith({double minScrollExtent, double maxScrollExtent, double pixels, double viewportDimension, AxisDirection axisDirection }) → 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. [...]
inherited
correctPixels(double value) → void: Change the value of pixels to the new value, without notifying any customers. [...]
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
didUpdateScrollPositionBy(double delta) → void: Called by setPixels to report a change to the pixels position.
inherited
ensureVisible(RenderObject object, { double alignment: 0.0, Duration duration: Duration.zero, Curve curve: Curves.ease }) → 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. [...]
@protected, 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 non-existent method or property is accessed. [...]
inherited
notifyListeners() → void: Call all the registered listeners. [...]
inherited
removeListener(VoidCallback listener) → void: Remove a previously registered closure from the list of closures that are notified when the object changes. [...]
inherited
restoreScrollOffset() → void: Called whenever the ScrollPosition is created, to restore the scroll offset if possible. [...]
@protected, 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. [...]
@protected, inherited
toString() → String: Returns a string representation of this object.
inherited

Operators

operator ==(dynamic other) → bool: The equality operator. [...]
inherited

widgets library

ScrollPositionWithSingleContext class

Constructors

Properties

Methods

Operators