ViewportOffset class Null safety

Which part of the content inside the viewport should be visible.

The pixels value determines the scroll offset that the viewport uses to select which part of its content to display. As the user scrolls the viewport, this value changes, which changes the content that is displayed.

This object is a Listenable that notifies its listeners when pixels changes.

Constructors

ViewportOffset(): Default constructor.
ViewportOffset.fixed(double value): Creates a viewport offset with the given pixels value.
factory
ViewportOffset.zero(): Creates a viewport offset with a pixels value of 0.0.
factory

Properties

allowImplicitScrolling → bool: Whether a viewport is allowed to change pixels implicitly to respond to a call to RenderObject.showOnScreen.
read-only
hashCode → int: The hash code for this object.
read-onlyinherited
hasListeners → bool: Whether any listeners are currently registered.
protected">@protectedread-onlyinherited
hasPixels → bool: Whether the pixels property is available.
read-only
pixels → double: The number of pixels to offset the children in the opposite of the axis direction.
read-only
runtimeType → Type: A representation of the runtime type of the object.
read-onlyinherited
userScrollDirection → ScrollDirection: The direction in which the user is trying to change pixels, relative to the viewport's RenderViewportBase.axisDirection.
read-only

Methods

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 pixels from its current value to the given value.
applyContentDimensions(double minScrollExtent, double maxScrollExtent) → bool: Called when the viewport's content extents are established.
applyViewportDimension(double viewportDimension) → bool: Called when the viewport's extents are established.
correctBy(double correction) → void: Apply a layout-time correction to the scroll offset.
debugFillDescription(List<String> description) → void: Add additional information to the given description for use by toString.
mustCallSuper">@mustCallSuper
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).
mustCallSuper">@mustCallSuperinherited
jumpTo(double pixels) → void: Jumps pixels from its current value to the given value, without animation, and without checking if the new value is in range.
moveTo(double to, {Duration? duration, Curve? curve, bool? clamp}) → Future<void>: Calls jumpTo if duration is null or Duration.zero, otherwise animateTo is called.
noSuchMethod(Invocation invocation) → dynamic: Invoked when a non-existent method or property is accessed.
inherited
notifyListeners() → void: Call all the registered listeners.
protected">@protectedvisibleForTesting">@visibleForTestinginherited
removeListener(VoidCallback listener) → void: Remove a previously registered closure from the list of closures that are notified when the object changes.
inherited
toString() → String: A string representation of this object.
override

Operators

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

ViewportOffset class Null safety

Constructors

Properties

Methods

Operators

rendering library