TimelineTileBuilderDelegate class Null safety

The widgets returned from the builder callback are automatically wrapped in AutomaticKeepAlive widgets if addAutomaticKeepAlives is true (the default) and in RepaintBoundary widgets if addRepaintBoundaries is true (also the default).

Accessibility

The CustomScrollView requires that its semantic children are annotated using IndexedSemantics. This is done by default in the delegate with the addSemanticIndexes parameter set to true.

If multiple delegates are used in a single scroll view, then the indexes will not be correct by default. The semanticIndexOffset can be used to offset the semantic indexes of each delegate so that the indexes are monotonically increasing. For example, if a scroll view contains two delegates where the first has 10 children contributing semantics, then the second delegate should offset its children by 10.

See also:

  • IndexedSemantics, for an example of manually annotating child nodes with semantic indexes.
Inheritance

Constructors

TimelineTileBuilderDelegate(NullableIndexedWidgetBuilder builder, {ChildIndexGetter? findChildIndexCallback, int? childCount, bool addAutomaticKeepAlives = true, bool addRepaintBoundaries = true, bool addSemanticIndexes = true, SemanticIndexCallback semanticIndexCallback = _kDefaultSemanticIndexCallback, int semanticIndexOffset = 0})

Properties

addAutomaticKeepAlives bool
Whether to wrap each child in an AutomaticKeepAlive.
finalinherited
addRepaintBoundaries bool
Whether to wrap each child in a RepaintBoundary.
finalinherited
addSemanticIndexes bool
Whether to wrap each child in an IndexedSemantics.
finalinherited
builder NullableIndexedWidgetBuilder
Called to build children for the sliver.
finalinherited
childCount int?
The total number of children this delegate can provide.
finalinherited
estimatedChildCount int?
Returns an estimate of the number of children this delegate will build.
read-onlyinherited
findChildIndexCallback ChildIndexGetter?
Called to find the new index of a child based on its key in case of reordering.
finalinherited
hashCode int
The hash code for this object.
read-onlyinherited
runtimeType Type
A representation of the runtime type of the object.
read-onlyinherited
semanticIndexCallback SemanticIndexCallback
A SemanticIndexCallback which is used when addSemanticIndexes is true.
finalinherited
semanticIndexOffset int
An initial offset to add to the semantic indexes generated by this widget.
finalinherited

Methods

build(BuildContext context, int index) Widget?
Returns the child with the given index.
inherited
debugFillDescription(List<String> description) → void
Add additional information to the given description for use by toString.
didFinishLayout(int firstIndex, int lastIndex) → void
Called at the end of layout to indicate that layout is now complete.
inherited
estimateMaxScrollOffset(int firstIndex, int lastIndex, double leadingScrollOffset, double trailingScrollOffset) double?
Returns an estimate of the max scroll extent for all the children.
inherited
findIndexByKey(Key key) int?
Find index of child element with associated key.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
inherited
shouldRebuild(covariant SliverChildBuilderDelegate oldDelegate) bool
Called whenever a new instance of the child delegate class is provided to the sliver.
inherited
toString() String
A string representation of this object.
inherited

Operators

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