dispose method

  1. @override
void dispose ()
override

Releases any resources used by the object.

This method is called by the owner of this gesture recognizer when the object is no longer needed (e.g. when a gesture recognizer is being unregistered from a GestureDetector, the GestureDetector widget calls this method).

Implementation 

@override
void dispose() {
  _pointers.keys.toList().forEach(_removeState);
  assert(_pointers.isEmpty);
  _pointers = null;
  super.dispose();
}