SliverChildBuilderDelegate class

A delegate that supplies children for slivers using a builder callback.

Many slivers lazily construct their box children to avoid creating more children than are visible through the Viewport. This delegate provides children using an IndexedWidgetBuilder callback, so that the children do not even have to be built until they are displayed.

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).

See also:



SliverChildBuilderDelegate(IndexedWidgetBuilder builder, { int childCount, bool addAutomaticKeepAlives: true, bool addRepaintBoundaries: true })
Creates a delegate that supplies children for slivers using the given builder callback. [...]


addAutomaticKeepAlives bool
Whether to wrap each child in an AutomaticKeepAlive. [...]
addRepaintBoundaries bool
Whether to wrap each child in a RepaintBoundary. [...]
builder IndexedWidgetBuilder
Called to build children for the sliver. [...]
childCount int
The total number of children this delegate can provide. [...]
estimatedChildCount int
Returns an estimate of the number of children this delegate will build. [...]
hashCode int
The hash code for this object. [...]
read-only, inherited
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited


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


operator ==(dynamic other) bool
The equality operator. [...]