LayoutGrid.countBuilder constructor

LayoutGrid.countBuilder({
  1. Key? key,
  2. Axis scrollDirection = Axis.vertical,
  3. bool reverse = false,
  4. ScrollController? controller,
  5. bool? primary,
  6. ScrollPhysics? physics,
  7. bool shrinkWrap = false,
  8. EdgeInsetsGeometry? padding,
  9. required int crossAxisCount,
  10. required IndexedWidgetBuilder itemBuilder,
  11. int? itemCount,
  12. double mainAxisSpacing = 0.0,
  13. double crossAxisSpacing = 0.0,
  14. bool addAutomaticKeepAlives = true,
  15. bool addRepaintBoundaries = true,
})

Creates a scrollable, 2D array of widgets of variable sizes with a fixed number of cells 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 SliverLayoutGridDelegateWithFixedCrossAxisCount as the gridDelegate.

Providing a non-null itemCount improves the ability of the SliverLayoutGridDelegate to estimate the maximum scroll extent.

itemBuilder will be called only with indices greater than or equal to zero and less than itemCount.

The addAutomaticKeepAlives argument corresponds to the SliverLayoutGridDelegate.addAutomaticKeepAlives property. The addRepaintBoundaries argument corresponds to the SliverLayoutGridDelegate.addRepaintBoundaries property. Both must not be null.

Implementation

LayoutGrid.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,
  int? itemCount,
  double mainAxisSpacing: 0.0,
  double crossAxisSpacing: 0.0,
  bool addAutomaticKeepAlives: true,
  bool addRepaintBoundaries: true,
})  : gridDelegate = SliverLayoutGridDelegateWithFixedCrossAxisCount(
        crossAxisCount: crossAxisCount,
        mainAxisSpacing: mainAxisSpacing,
        crossAxisSpacing: crossAxisSpacing,
      ),
      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,
      );