StaggeredGridView.countBuilder constructor
- Key? key,
- Axis scrollDirection = Axis.vertical,
- bool reverse = false,
- ScrollController? controller,
- bool? primary,
- ScrollPhysics? physics,
- bool shrinkWrap = false,
- EdgeInsetsGeometry? padding,
- required int crossAxisCount,
- required IndexedWidgetBuilder itemBuilder,
- required IndexedStaggeredTileBuilder staggeredTileBuilder,
- int? itemCount,
- double mainAxisSpacing = 0.0,
- double crossAxisSpacing = 0.0,
- bool addAutomaticKeepAlives = true,
- bool addRepaintBoundaries = true,
- String? restorationId,
Creates a scrollable, 2D array of widgets of variable sizes with a fixed number of tiles in the cross axis that are created on demand.
This constructor is appropriate for grid views with a large (or infinite) number of children because the builder is called only for those children that are actually visible.
Uses a SliverStaggeredGridDelegateWithFixedCrossAxisCount as the gridDelegate.
Providing a non-null itemCount
improves the ability of the
SliverStaggeredGridDelegate to estimate the maximum scroll extent.
itemBuilder
and staggeredTileBuilder
will be called only with
indices greater than or equal to
zero and less than itemCount
.
The addAutomaticKeepAlives
argument corresponds to the
SliverVariableSizeChildListDelegate.addAutomaticKeepAlives
property. The
addRepaintBoundaries
argument corresponds to the
SliverVariableSizeChildListDelegate.addRepaintBoundaries
property. Both must not be
null.
Implementation
StaggeredGridView.countBuilder({
Key? key,
Axis scrollDirection = Axis.vertical,
bool reverse = false,
ScrollController? controller,
bool? primary,
ScrollPhysics? physics,
bool shrinkWrap = false,
EdgeInsetsGeometry? padding,
required int crossAxisCount,
required IndexedWidgetBuilder itemBuilder,
required IndexedStaggeredTileBuilder staggeredTileBuilder,
int? itemCount,
double mainAxisSpacing = 0.0,
double crossAxisSpacing = 0.0,
bool addAutomaticKeepAlives = true,
bool addRepaintBoundaries = true,
String? restorationId,
}) : gridDelegate = SliverStaggeredGridDelegateWithFixedCrossAxisCount(
crossAxisCount: crossAxisCount,
mainAxisSpacing: mainAxisSpacing,
crossAxisSpacing: crossAxisSpacing,
staggeredTileBuilder: staggeredTileBuilder,
staggeredTileCount: itemCount,
),
childrenDelegate = SliverChildBuilderDelegate(
itemBuilder,
childCount: itemCount,
addAutomaticKeepAlives: addAutomaticKeepAlives,
addRepaintBoundaries: addRepaintBoundaries,
),
super(
key: key,
scrollDirection: scrollDirection,
reverse: reverse,
controller: controller,
primary: primary,
physics: physics,
shrinkWrap: shrinkWrap,
padding: padding,
restorationId: restorationId,
);