I have a provider where a method , by this method if I send lat and long it will give me place name.

Future<List<Placemark>> getAndSetAddressFromLatLong(double startLat)async {
        List<Placemark> placemarksStart = await placemarkFromCoordinates(startLat,startLong);
        return placemarksStart;
}

So, When I'm trying to call and fetch the data in view file like below

@override
Widget build(BuildContext context) {

var data = Provider.of<MapProvider>(context).getAndSetAddressFromLatLong(
    widget.history.startLat!.toDouble(), 
    widget.history.startLong!.toDouble(),
).then((value) => value);

print(data);

I'm getting the output I/flutter (25255): Instance of 'Future<List<Placemark>>' , But In then() if I print value without return I'm getting my desire list.

How I will get List<Placemark> here from Instance of 'Future<List>' ?

CodePudding user response：

late List<placemark> data;
@override
Widget build(BuildContext context) {

Provider.of<MapProvider>(context).getAndSetAddressFromLatLong(
    widget.history.startLat!.toDouble(), 
    widget.history.startLong!.toDouble(),
).then((value){
  data = value;
  print(data);
}
);

CodePudding user response：

Since you're using provider call notifyListeners() after awaiting the results. In the widget use consumer to show the results

List<Placemark> _placemarksStart = [];
List<Placemark> get placemarksStart => [..._placemarksStart];

Future<void> getAndSetAddressFromLatLong(double startLat, double startLong) async {
    _placemarksStart = await placemarkFromCoordinates(startLat,startLong);
    notifyListeners();
}

Widget, similarly you can achieve loading with a boolean

Consumer<MyType>(
  builder: (context, provider, child) {
    if (provider.placemarksStart.isEmpty) {
      return Center(child: Text('Loading...'),);
    }
    return ListView.builder(itemBuilder: (context, index) {
      final item = provider.placemarksStart[index];
      return Text("TODO");
    }, itemCount: provider.placemarksStart.length,);
  },
),

And call the method getAndSetAddressFromLatLong in the initState