GridView.builder constructor

GridView.builder({Key key, Axis scrollDirection: Axis.vertical, bool reverse: false, ScrollController controller, bool primary, ScrollPhysics physics, bool shrinkWrap: false, EdgeInsetsGeometry padding, @required SliverGridDelegate gridDelegate, @required IndexedWidgetBuilder itemBuilder, int itemCount, bool addAutomaticKeepAlives: true, bool addRepaintBoundaries: true, bool addSemanticIndexes: true, double cacheExtent, int semanticChildCount })

Creates a scrollable, 2D array of widgets 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 GridView 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 

GridView.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,
}) : assert(gridDelegate != null),
     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,
     );