onSemanticsAction property

SemanticsActionCallback onSemanticsAction

A callback that is invoked whenever the user requests an action to be performed.

This callback is used when the user expresses the action they wish to perform based on the semantics supplied by updateSemantics.

The framework invokes this callback in the same zone in which the callback was set.

Implementation 

SemanticsActionCallback get onSemanticsAction => _onSemanticsAction;
void onSemanticsAction= (SemanticsActionCallback callback)

Implementation 

set onSemanticsAction(SemanticsActionCallback callback) {
  _onSemanticsAction = callback;
  _onSemanticsActionZone = Zone.current;
}