import 'dart:async'; import 'package:flutter_tts/flutter_tts.dart'; class RobotProvider { static final RobotProvider _singleton = RobotProvider._internal(); var value; StreamController controller = StreamController.broadcast(); FlutterTts flutterTts = FlutterTts(); getData() { // return data; } intStream() { controller.add({}); } setValue(Map data) { value = data; controller.add(value); } factory RobotProvider() { return _singleton; } RobotProvider._internal(); speak(data) async { await flutterTts.speak(data); } }