“andamio de fluter.of () llamado con un contexto que no contiene un andamio” Código de respuesta

andamio de fluter.of () llamado con un contexto que no contiene un andamio

This exception happens because you are using the context of the widget that
instantiated Scaffold.
Not the context of a child of Scaffold.
You can solve this by just using a different context :

Scaffold(
    appBar: AppBar(
        title: Text('SnackBar Playground'),
    ),
    body: Builder(
        builder: (context) => 
            Center(
            child: RaisedButton(
            color: Colors.pink,
            textColor: Colors.white,
            onPressed: () => _displaySnackBar(context),
            child: Text('Display SnackBar'),
            ),
        ),
    ),
);