Draggable<T> constructor

const Draggable<T>({Key key, @required Widget child, @required Widget feedback, T data, Axis axis, Widget childWhenDragging, Offset feedbackOffset: Offset.zero, DragAnchor dragAnchor: DragAnchor.child, Axis affinity, int maxSimultaneousDrags, VoidCallback onDragStarted, DraggableCanceledCallback onDraggableCanceled, DragEndCallback onDragEnd, VoidCallback onDragCompleted, bool ignoringFeedbackSemantics: true })

Creates a widget that can be dragged to a DragTarget.

The child and feedback arguments must not be null. If maxSimultaneousDrags is non-null, it must be non-negative.

Implementation 

const Draggable({
  Key key,
  @required this.child,
  @required this.feedback,
  this.data,
  this.axis,
  this.childWhenDragging,
  this.feedbackOffset = Offset.zero,
  this.dragAnchor = DragAnchor.child,
  this.affinity,
  this.maxSimultaneousDrags,
  this.onDragStarted,
  this.onDraggableCanceled,
  this.onDragEnd,
  this.onDragCompleted,
  this.ignoringFeedbackSemantics = true,
}) : assert(child != null),
     assert(feedback != null),
     assert(ignoringFeedbackSemantics != null),
     assert(maxSimultaneousDrags == null || maxSimultaneousDrags >= 0),
     super(key: key);