ExtendedSliverFixedExtentList class

A sliver that places multiple box children with the same main axis extent in a linear array.

ExtendedSliverFixedExtentList places its children in a linear array along the main axis starting at offset zero and without gaps. Each child is forced to have the itemExtent in the main axis and the SliverConstraints.crossAxisExtent in the cross axis.

ExtendedSliverFixedExtentList is more efficient than ExtendedSliverList because ExtendedSliverFixedExtentList does not need to perform layout on its children to obtain their extent in the main axis.

{@tool sample}

This example, which would be inserted into a CustomScrollView.slivers list, shows an infinite number of items in varying shades of blue:

SliverFixedExtentList(
  itemExtent: 50.0,
  delegate: SliverChildBuilderDelegate(
    (BuildContext context, int index) {
      return Container(
        alignment: Alignment.center,
        color: Colors.lightBlue[100 * (index % 9)],
        child: Text('list item $index'),
      );
    },
  ),
)

{@end-tool}

See also:

• SliverPrototypeExtentList, which is similar to ExtendedSliverFixedExtentList except that it uses a prototype list item instead of a pixel value to define the main axis extent of each item.
• SliverFillViewport, which determines the itemExtent based on SliverConstraints.viewportMainAxisExtent.
• ExtendedSliverList, which does not require its children to have the same extent in the main axis.

Inheritance

• Object
• DiagnosticableTree
• Widget
• RenderObjectWidget
• SliverWithKeepAliveWidget
• SliverMultiBoxAdaptorWidget
• ExtendedSliverFixedExtentList

Available Extensions

• WidgetMarginX
• WidgetPaddingX
• WidgetSliverBoxX

Constructors

ExtendedSliverFixedExtentList({Key? key, required SliverChildDelegate delegate, required double itemExtent, required ExtendedListDelegate extendedListDelegate})

Creates a sliver that places box children with the same main axis extent in a linear array.

const

Properties

delegate → SliverChildDelegate

The delegate that provides the children for this widget.

final, inherited

extendedListDelegate → ExtendedListDelegate

A delegate that provides extensions within the ExtendedGridView/ExtendedList/WaterfallFlow.

final

hashCode → int

The hash code for this object.

no setter, inherited

itemExtent → double

The extent the children are forced to have in the main axis.

final

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

createElement() → SliverMultiBoxAdaptorElement

RenderObjectWidgets always inflate to a RenderObjectElement subclass.

inherited

createRenderObject(BuildContext context) → ExtendedRenderSliverFixedExtentList

Creates an instance of the RenderObject class that this RenderObjectWidget represents, using the configuration described by this RenderObjectWidget.

override

debugDescribeChildren() → List<DiagnosticsNode>

Returns a list of DiagnosticsNode objects describing this node's children.

inherited

debugFillProperties(DiagnosticPropertiesBuilder properties) → void

Add additional properties associated with the node.

inherited

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.

inherited

estimateMaxScrollOffset(SliverConstraints? constraints, int firstIndex, int lastIndex, double leadingScrollOffset, double trailingScrollOffset) → double?

Returns an estimate of the max scroll extent for all the children.

inherited

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode

Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.

inherited

toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String

A string representation of this object.

inherited

toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String

Returns a string representation of this node and its descendants.

inherited

toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String

Returns a one-line detailed description of the object.

inherited

toStringShort() → String

A short, textual description of this widget.

inherited

updateRenderObject(BuildContext context, covariant ExtendedRenderSliverFixedExtentList 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.

override

Operators

operator ==(Object other) → bool

The equality operator.

inherited