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
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.
finalinherited
- extendedListDelegate → ExtendedListDelegate
-
A delegate that provides extensions within the
ExtendedGridView/ExtendedList/WaterfallFlow
.final - hashCode → int
-
The hash code for this object.
no setterinherited
- 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.
finalinherited
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
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