Is there any way to achieve a Flutter top snackbar?

You can use https://pub.dartlang.org/packages/flushbar

RaisedButton(
  child: Text('Show Top Snackbar'),
  onPressed: () {
    Flushbar(
      flushbarPosition: FlushbarPosition.TOP,
    )
      ..title = "Hey Ninja"
      ..message = "Lorem Ipsum is simply dummy text of the printing and typesetting industry"
      ..duration = Duration(seconds: 3)
      ..show(context);
  },
),