ListWheelViewport class Null safety

A viewport showing a subset of children on a wheel.

Typically used with ListWheelScrollView, this viewport is similar to Viewport in that it shows a subset of children in a scrollable based on the scrolling offset and the children's dimensions. But uses RenderListWheelViewport to display the children on a wheel.

See also:



ListWheelViewport({Key? key, double diameterRatio = RenderListWheelViewport.defaultDiameterRatio, double perspective = RenderListWheelViewport.defaultPerspective, double offAxisFraction = 0.0, bool useMagnifier = false, double magnification = 1.0, double overAndUnderCenterOpacity = 1.0, required double itemExtent, double squeeze = 1.0, bool renderChildrenOutsideViewport = false, required ViewportOffset offset, required ListWheelChildDelegate childDelegate, Clip clipBehavior = Clip.hardEdge})
Creates a viewport where children are rendered onto a wheel.


childDelegate ListWheelChildDelegate
A delegate that lazily instantiates children.
clipBehavior Clip
The content will be clipped (or not) according to this option.
diameterRatio double
A ratio between the diameter of the cylinder and the viewport's size in the main axis.
hashCode int
The hash code for this object.
@nonVirtual, read-only, inherited
itemExtent double
The size of the children along the main axis. Children RenderBoxes will be given the BoxConstraints of this exact size.
key Key?
Controls how one widget replaces another widget in the tree.
final, inherited
magnification double
The zoomed-in rate of the magnifier, if it is used.
offAxisFraction double
How much the wheel is horizontally off-center, as a fraction of its width. This property creates the visual effect of looking at a vertical wheel from its side where its vanishing points at the edge curves to one side instead of looking at the wheel head-on.
offset ViewportOffset
ViewportOffset object describing the content that should be visible in the viewport.
overAndUnderCenterOpacity double
The opacity value that will be applied to the wheel that appears below and above the magnifier.
perspective double
Perspective of the cylindrical projection.
renderChildrenOutsideViewport bool
Whether to paint children inside the viewport only.
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited
squeeze double
The angular compactness of the children on the wheel.
useMagnifier bool
Whether to use the magnifier for the center item of the wheel.


createElement() ListWheelElement
RenderObjectWidgets always inflate to a RenderObjectElement subclass.
createRenderObject(BuildContext context) RenderListWheelViewport
Creates an instance of the RenderObject class that this RenderObjectWidget represents, using the configuration described by this RenderObjectWidget.
debugDescribeChildren() List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children.
@protected, inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
didUnmountRenderObject(covariant RenderObject renderObject) → void
A render object previously associated with this widget has been removed from the tree. The given RenderObject will be of the same type as returned by this object's createRenderObject.
@protected, inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) DiagnosticsNode
Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
toString({DiagnosticLevel minLevel =}) String
A string representation of this object.
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug}) String
Returns a string representation of this node and its descendants.
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) String
Returns a one-line detailed description of the object.
toStringShort() String
A short, textual description of this widget.
updateRenderObject(BuildContext context, covariant RenderListWheelViewport renderObject) → void
Copies the configuration described by this RenderObjectWidget to the given RenderObject, which will be of the same type as returned by this object's createRenderObject.


operator ==(Object other) bool
The equality operator.
@nonVirtual, inherited