Question 88737 in Flutter Question posted in
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STREAMBUILDE with boolean values – Flutter

I need to how to handle a stream builder with boolean data.

I need to know how to send bool data to my StreamBuilder in the HomePage,
I was using (!snapshot.hasData) but this method only see if theres data or not no matter if they are true or false.

and i need that know the difference betwen false and true,
to show me a widget only when geolocator returns true and another widget only when it returns false

HOMEPAGE


  @override
  Widget build(BuildContext context) {
    final locationService = Provider.of<GeolocatorService>(context);

    return Scaffold(
        body: StreamBuilder(
            stream: locationService.refreshLocation,
            builder: (BuildContext context, AsyncSnapshot snapshot) {
              if (!snapshot.hasData) {
                return _EnableGpsMessage();
              }
              return _AccessButton();
            }));
  }
}





PROVIDER

  bool _gpsEnabled = false;

  bool get gpsEnabled => _gpsEnabled;
  set gpsEnabled(bool value) {
    _gpsEnabled = value;
    notifyListeners();
  }

  final StreamController _refreshLocation = new StreamController.broadcast();

  Stream get refreshLocation => this._refreshLocation.stream;



  _checkGpsStatus() async {
    final isEnabled = await Geolocator.isLocationServiceEnabled();
    print('FROM GEOLOCATOR SERVICE $isEnabled');
    // this._refreshLocation.sink.add(isEnabled);

    Geolocator.getServiceStatusStream().listen((event) {
      final statusStream =
          (event.index == 1) ? gpsEnabled = true : gpsEnabled = false;
      print(statusStream);

      this._refreshLocation.sink.add(statusStream);
    });
    // return (!isEnabled) ? gpsEnabled = false : gpsEnabled = true;
  }
Tags:

3

Answers


  1. 0

    snapshot.data is the one which contains the value (which can be bool, Object, or something else).

    hasData is the method to know if data is available or not.

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  2. 0

    To show different widgets based on the boolean value received in a StreamBuilder, you can use this code also i have explain in comments for your help –

    @override
Widget build(BuildContext context) {
  final locationService = Provider.of<GeolocatorService>(context);

  return Scaffold(
    body: StreamBuilder(
      stream: locationService.refreshLocation,
      builder: (BuildContext context, AsyncSnapshot<bool> snapshot) {
        if (!snapshot.hasData) {
          return _EnableGpsMessage();
        } else if (snapshot.data!) { // `!` is used to mark `data` as non-null
          return _AccessButton(); // Show this widget when the data is `true`
        } else {
          return _DisableGpsMessage(); // Show this widget when the data is `false`
        }
      },
    ),
  );
}

    And in the provider, where you handle the GPS status changes, you can update the stream with the boolean value like this –

    _checkGpsStatus() async {
  final isEnabled = await Geolocator.isLocationServiceEnabled();
  print('FROM GEOLOCATOR SERVICE $isEnabled');

  final statusStream = (isEnabled) ? true : false; // Get the boolean value
  gpsEnabled = statusStream; // Update the state of the provider

  this._refreshLocation.sink.add(statusStream); // Send the boolean value through the stream
}

    i hope it will work let me know if it works or not..

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  3. 0

    The value is in snapshot.data:

    if (snapshot.hasData) { 
  if (snapshot.data ?? false) {
    return TrueWidget();
  }
  else {
    return FalseWidget();
  } 
}
return LoadingWidget();
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