KeyboardVisibilityController constructor Null safety


Constructs a singleton instance of KeyboardVisibilityController.

KeyboardVisibilityController is designed to work as a singleton.


// When a second instance is created, the first instance will not be able to listen to the
// EventChannel because it is overridden. Forcing the class to be a singleton class can prevent
// misuse of creating a second instance from a programmer.
factory KeyboardVisibilityController() => _instance;