Question 161673 in Flutter Question posted in
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How can MylocationCountry values appear in the Text() appbar in Flutter?

I want to display the value of MyLocationCountry in the appbar text, but the data is null. Meanwhile, when I make print($MyLocationCountry) the data is there. I want to try displaying country location data to my appbar and I am confused why the value data on Mylocationcountry does not appear in text form

This my code

`
Class _HomePageState extends State<HomePage> {
  int currentIndexPage = 0;

  final location = new Location();
  String? locationError;
  String? MylocationCountry, MylocationCity;
  PrayerTimes? prayerTimes;
  double? latitude, longitude, pLat, pLong;

  @override
  void initState() {

    getLocationData().then((locationData) async {
      if (!mounted) {
        return;
      }
      if (locationData != null)  {

        setState(() {
          prayerTimes = PrayerTimes(
              Coordinates(locationData.latitude, locationData.longitude),
              DateComponents.from(DateTime.now()),
              CalculationMethod.karachi.getParameters());
          pLat = prayerTimes!.coordinates.latitude;
          pLong = prayerTimes!.coordinates.longitude;
          print("Latitude : $pLat, Longitude : $pLong");
        });
      } else {
        setState(() {
          locationError = "Couldn't Get Your Location!";
        });
      }
      List<MyLocation.Placemark> placemarks = await MyLocation.placemarkFromCoordinates(pLat!, pLong!);
      MylocationCountry = placemarks.reversed.last.country.toString();
      MylocationCity = placemarks.reversed.last.locality.toString();
      print("Country : $MylocationCountry, City : $MylocationCity");
    });

    //DateTime.now().hour >= 18 && DateTime.now().hour <= 19

    super.initState();
  }


  @override
  Widget build(BuildContext context) {
    final country = this.MylocationCountry.toString();
    return Scaffold(
      appBar: PreferredSize(
        preferredSize: Size.fromHeight(225),
        child: AppBar(
          automaticallyImplyLeading: false,
          title: RichText(
            text: TextSpan(
                text: country,
                style: TextStyle(
                  fontSize: 20,
                  fontWeight: FontWeight.w500,
                ),
                children:
                <TextSpan>[
                  TextSpan(
                    text: "n$MylocationCity",
                    style: TextStyle(
                      fontSize: 16,
                      fontWeight: FontWeight.normal,
                    ),
                  ),
                ]),),

`

The data is not show when i make the code like this, maybe someone can help me?

Tags:

3

Answers


  1. 0

    If you look at the code carefully, you will see that you are not calling setState after setting the value of MylocationCountry.

    Here is an updated code snippet:

    setState(() {
          List<MyLocation.Placemark> placemarks =
              await MyLocation.placemarkFromCoordinates(pLat!, pLong!);
          MylocationCountry = placemarks.reversed.last.country.toString();
          MylocationCity = placemarks.reversed.last.locality.toString();
        });
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  2. 0

    I suggest you a futureBuilder approach that could be helpful:

    class _HomePageState extends State<HomePage> {
  ...

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: PreferredSize(
        preferredSize: Size.fromHeight(225),
        child: FutureBuilder(
          future: MyLocation.placemarkFromCoordinates(pLat!, pLong!),
          builder: (BuildContext context, AsyncSnapshot<List<MyLocation.Placemark>> snapshot) {
            if (snapshot.hasData) {
              MylocationCountry = snapshot.data!.reversed.last.country.toString();
              MylocationCity = snapshot.data!.reversed.last.locality.toString();
            }
            return AppBar(
              automaticallyImplyLeading: false,
              title: RichText(
                text: TextSpan(
                  text: MylocationCountry ?? '',
                  style: TextStyle(
                    fontSize: 20,
                    fontWeight: FontWeight.w500,
                  ),
                  children: <TextSpan>[
                    TextSpan(
                      text: "n${MylocationCity ?? ''}",
                      style: TextStyle(
                        fontSize: 16,
                        fontWeight: FontWeight.normal,
                      ),
                    ),
                  ],
                ),
              ),
            );
          },
        ),
      ),
      ...
    );
  }
}
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  3. 0

    MyLocation.placemarkFromCoordinates is asynchronous so it’ll execute with some delay which means your build function runs before placemarks data is available. You need to update state after this call finishes.

    setState((){
  MylocationCountry = placemarks.reversed.last.country.toString();
  MylocationCity = placemarks.reversed.last.locality.toString();
})
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