WaterfallFlow.builder constructor
- Key? key,
- Axis scrollDirection = Axis.vertical,
- bool reverse = false,
- ScrollController? controller,
- bool? primary,
- ScrollPhysics? physics,
- bool shrinkWrap = false,
- EdgeInsetsGeometry? padding,
- required SliverWaterfallFlowDelegate gridDelegate,
- required IndexedWidgetBuilder itemBuilder,
- int? itemCount,
- bool addAutomaticKeepAlives = true,
- bool addRepaintBoundaries = true,
- bool addSemanticIndexes = true,
- double? cacheExtent,
- int? semanticChildCount,
- DragStartBehavior dragStartBehavior = DragStartBehavior.start,
- ScrollViewKeyboardDismissBehavior keyboardDismissBehavior = ScrollViewKeyboardDismissBehavior.manual,
- String? restorationId,
- Clip clipBehavior = Clip.hardEdge,
Creates a scrollable, 2D array of widgets whose size is variable in the main 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.
Providing a non-null itemCount
improves the ability of the WaterfallFlow to
estimate the maximum scroll extent.
itemBuilder
will be called only with indices greater than or equal to
zero and less than itemCount
.
The gridDelegate
argument must not be null.
The addAutomaticKeepAlives
argument corresponds to the
SliverChildBuilderDelegate.addAutomaticKeepAlives property. The
addRepaintBoundaries
argument corresponds to the
SliverChildBuilderDelegate.addRepaintBoundaries property. Both must not
be null.
Implementation
WaterfallFlow.builder({
Key? key,
Axis scrollDirection = Axis.vertical,
bool reverse = false,
ScrollController? controller,
bool? primary,
ScrollPhysics? physics,
bool shrinkWrap = false,
EdgeInsetsGeometry? padding,
required this.gridDelegate,
required IndexedWidgetBuilder itemBuilder,
int? itemCount,
bool addAutomaticKeepAlives = true,
bool addRepaintBoundaries = true,
bool addSemanticIndexes = true,
double? cacheExtent,
int? semanticChildCount,
DragStartBehavior dragStartBehavior = DragStartBehavior.start,
ScrollViewKeyboardDismissBehavior keyboardDismissBehavior =
ScrollViewKeyboardDismissBehavior.manual,
String? restorationId,
Clip clipBehavior = Clip.hardEdge,
}) : childrenDelegate = SliverChildBuilderDelegate(
itemBuilder,
childCount: itemCount,
addAutomaticKeepAlives: addAutomaticKeepAlives,
addRepaintBoundaries: addRepaintBoundaries,
addSemanticIndexes: addSemanticIndexes,
),
super(
key: key,
scrollDirection: scrollDirection,
reverse: reverse,
controller: controller,
primary: primary,
physics: physics,
shrinkWrap: shrinkWrap,
padding: padding,
cacheExtent: cacheExtent,
semanticChildCount: semanticChildCount ?? itemCount,
dragStartBehavior: dragStartBehavior,
keyboardDismissBehavior: keyboardDismissBehavior,
restorationId: restorationId,
clipBehavior: clipBehavior,
);