onSemanticsAction property Null safety

SemanticsActionCallback? onSemanticsAction

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

Accessing this value returns the value contained in the PlatformDispatcher singleton, so instead of getting it from here, you should consider getting it from WidgetsBinding.instance.platformDispatcher instead (or, when WidgetsBinding isn't available, from PlatformDispatcher.instance). The reason this value forwards to the PlatformDispatcher is to provide convenience for applications that only use a single main window.

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.


SemanticsActionCallback? get onSemanticsAction => platformDispatcher.onSemanticsAction;
void onSemanticsAction=(SemanticsActionCallback? callback)


set onSemanticsAction(SemanticsActionCallback? callback) {
  platformDispatcher.onSemanticsAction = callback;