FocusTraversalGroup constructor Null safety

FocusTraversalGroup(
  1. {Key? key,
  2. FocusTraversalPolicy? policy,
  3. bool descendantsAreFocusable,
  4. required Widget child}
)

Creates a FocusTraversalGroup object.

The child and descendantsAreFocusable arguments must not be null.

Implementation

FocusTraversalGroup({
  Key? key,
  FocusTraversalPolicy? policy,
  this.descendantsAreFocusable = true,
  required this.child,
})  : assert(descendantsAreFocusable != null),
      policy = policy ?? ReadingOrderTraversalPolicy(),
      super(key: key);