Stepper constructor Null safety

const Stepper(
  1. {Key? key,
  2. required List<Step> steps,
  3. ScrollPhysics? physics,
  4. StepperType type = StepperType.vertical,
  5. int currentStep = 0,
  6. ValueChanged<int>? onStepTapped,
  7. VoidCallback? onStepContinue,
  8. VoidCallback? onStepCancel,
  9. ControlsWidgetBuilder? controlsBuilder,
  10. double? elevation,
  11. EdgeInsetsGeometry? margin}
)

Creates a stepper from a list of steps.

This widget is not meant to be rebuilt with a different list of steps unless a key is provided in order to distinguish the old stepper from the new one.

The steps, type, and currentStep arguments must not be null.

Implementation

const Stepper({
  super.key,
  required this.steps,
  this.physics,
  this.type = StepperType.vertical,
  this.currentStep = 0,
  this.onStepTapped,
  this.onStepContinue,
  this.onStepCancel,
  this.controlsBuilder,
  this.elevation,
  this.margin,
}) : assert(steps != null),
     assert(type != null),
     assert(currentStep != null),
     assert(0 <= currentStep && currentStep < steps.length);