How to listen to stream value in dart/flutter

Question

Anyone Help to trace the position of audio (that is)

   if(durationtoOne(position==5)){
FlutterToast.Showtoast(msg:"I am At 5 sec");
}

I am Stuck on where to add this code if added in initstate got error, I want to listen the position throught the audio plats

Code Starts Here

  import 'dart:async';
    import 'package:assets_audio_player/assets_audio_player.dart';
    import 'package:flutter/material.dart';
    import 'package:fluttertoast/fluttertoast.dart';

    class SmartMantra extends StatefulWidget {
    @override
  _SmartMantraState createState() => _SmartMantraState();
}

class _SmartMantraState extends State<SmartMantra> {
  StreamSubscription _positionSubscription;
  Duration position;
  AssetsAudioPlayer _assetsAudioPlayer;


  stream() {
    _positionSubscription = _assetsAudioPlayer.currentPosition
        .listen((p) => setState(() => position = p),);
  }

  @override
  void initState() {
    _assetsAudioPlayer.open("assets/shivamantra.mp3");
    stream();
    _assetsAudioPlayer.finished.listen((finished) {
      print(finished);
//      print(count);
    });
    super.initState();
  }

  @override
  void dispose() {
    _positionSubscription.cancel();
    super.dispose();
  }
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: Column(
          children: <Widget>[
            SizedBox(
              height: 70,
            ),
            Center(
              child: Text(
               durationToone(position).toString(),
                style: TextStyle(color: Colors.black, fontSize: 12),
              ),
            ),
            //getTextContainer()
          ],
        ));
  }
int durationToone(Duration duration) {
  int twoDigits(int n) {
    if (n >= 10) return n;
    return n;
  }

  int twoDigitSeconds =
      twoDigits(duration.inSeconds.remainder(Duration.secondsPerMinute));
  return twoDigitSeconds;
}
}

Code Ends Here

Summary:At the specific Position needs to Trigger some Function While the Position Changes(I.e)

if(durationtoOne(position==5)){
FlutterToast.Showtoast(msg:"I am At 5 sec");
}

throught the audio plays or app is in foreground

Answer 1

If a stream is not a broadcast stream, you can listen to it only once.

Refer to this Medium post to know more about Streams.

You need to add your code in the stream function when listening to _assetsAudioPlayer.currentPosition.

import 'dart:async';
import 'package:assets_audio_player/assets_audio_player.dart';
import 'package:flutter/material.dart';
import 'package:fluttertoast/fluttertoast.dart';

class SmartMantra extends StatefulWidget {
    @override
    _SmartMantraState createState() => _SmartMantraState();
}

class _SmartMantraState extends State<SmartMantra> {
    StreamSubscription _positionSubscription;
    Duration position;
    AssetsAudioPlayer _assetsAudioPlayer;

    stream() {
        _positionSubscription = _assetsAudioPlayer.currentPosition
            .listen((p) {
                setState(() => position = p));
                // You should add your code here
                if(durationtoOne(position==5)){
                    FlutterToast.Showtoast(msg:"I am At 5 sec");
                }
            }
    }

    @override
    void initState() {
        _assetsAudioPlayer.open("assets/shivamantra.mp3");
        stream();
        _assetsAudioPlayer.finished.listen((finished) {
            print(finished);
//          print(count);
        });
        super.initState();
    }

    @override
    void dispose() {
        _positionSubscription.cancel();
        super.dispose();
    }

    @override
    Widget build(BuildContext context) {
        return Scaffold(
            body: Column(
                children: <Widget>[
                SizedBox(
                    height: 70,
                ),
                Center(
                    child: Text(
                        durationToone(position).toString(),
                        style: TextStyle(color: Colors.black, fontSize: 12),
                    ),
                ),
                //getTextContainer()
            ],
        ));
    }
    int durationToone(Duration duration) {
        int twoDigits(int n) {
            if (n >= 10) return n;
            return n;
        }

        int twoDigitSeconds =
            twoDigits(duration.inSeconds.remainder(Duration.secondsPerMinute));
        return twoDigitSeconds;
    }
}