WidgetBuilder typedef Null safety
Signature for a function that creates a widget, e.g. StatelessWidget.build or State.build.
Used by Builder.builder, OverlayEntry.builder, etc.
- IndexedWidgetBuilder, which is similar but also takes an index.
- TransitionBuilder, which is similar but also takes a child.
- ValueWidgetBuilder, which is similar but takes a value and a child.
typedef WidgetBuilder = Widget Function(BuildContext context);