I'm trying to convert an address to coordinates, I get the address using the Google Place API, what I get is a json object like this:

   "predictions" : [
      {
         "description" : "Nueva Galicia 342, Urdiñola, Saltillo, Coah., México",
         "matched_substrings" : [
            {
               "length" : 13,
               "offset" : 0
            },
            {
               "length" : 3,
               "offset" : 14
            }
         ],

My code is:

import 'dart:convert';
import 'package:http/http.dart';

class Suggestion {
  final String placeId;
  final String description;

  Suggestion(this.placeId, this.description);

  @override
  String toString() {
    return 'Suggestion(description: $description, placeId: $placeId)';
  }
}

class PlaceApiProvider {
  final client = Client();

  PlaceApiProvider(this.sessionToken);

  final sessionToken;

  final apiKey = 'API KEY';

  Future<List<Suggestion>> fetchSuggestions(
    String input,
  ) async {
    final request =
        'https://maps.googleapis.com/maps/api/place/autocomplete/json?input=$input&types=address&language=es-Es&components=country:mx&key=$apiKey&sessiontoken=$sessionToken';
    final response = await client.get(Uri.parse(request));

    final requestCoordinates =
        'https://maps.googleapis.com/maps/api/geocode/json?address=$address&key=$apiKey';
    final responseCoordinates = await client.get(Uri.parse(requestCoordinates));

    print(response.body);
    print(responseCoordinates.body);

    if (response.statusCode == 200) {
      final result = json.decode(response.body);

      if (result['status'] == 'OK') {
        return result['predictions']
            .map<Suggestion>((p) => Suggestion(p['place_id'], p['description']))
            .toList();
      }
      if (result['status'] == 'ZERO_RESULTS') {
        return [];
      }
      throw Exception(result['error_message']);
    } else {
      throw Exception('Failed to fetch suggestion');
    }
  }
}

I know that I need to get the description from the response, and then use it in the $address of the requestCoordinates, but I don't know how to do it, can someone help on this?

CodePudding user response：

you can use flutter_google_places package provide by flutter community.it give you google places autocomplete widgets. if you need code and explanation then let me know

CodePudding user response：

I implement the flutter_google_place package, but in the Flutter version that I'm using (2.10.1) the null safety version is causing me some issue. The code is this:

class SearchButton extends StatefulWidget {
  const SearchButton({Key? key}) : super(key: key);

  @override
  State<SearchButton> createState() => _SearchButtonState();
}

class _SearchButtonState extends State<SearchButton> {
  final _destinationController = TextEditingController();
  final ApiKey = "AIzaSyDUJ9IM2aSBxfQBozwn4aFt70FDaEGtfu0";

  @override
  void dispose() {
    _destinationController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final newLocation = Provider.of<ClientRequest>(context);
    final sessionToken = const Uuid().v4();
    Mode _mode = Mode.overlay;

    void one rror(PlacesAutocompleteResponse response) {
      SnackBar(
        content: Text(response.errorMessage),
      );
    }

    Future<void> displayPrediction(Prediction p) async {
      if (p != null) {
        GoogleMapsPlaces _places = GoogleMapsPlaces(
          apiKey: ApiKey,
          apiHeaders: await const GoogleApiHeaders().getHeaders(),
        );
        PlacesDetailsResponse detail =
            await _places.getDetailsByPlaceId(p.placeId);
        final lat = detail.result.geometry?.location.lat;
        final lng = detail.result.geometry?.location.lng;
        SnackBar(
          content: Text("${p.description} - $lat/$lng"),
        );
        print(detail);
      }
    }

    Future<void> _handlePressButton() async {
      Prediction p = await PlacesAutocomplete.show(
        context: context,
        apiKey: ApiKey,
        one rror: one rror,
        mode: _mode,
        language: "fr",
        decoration: InputDecoration(
          hintText: 'Search',
          focusedBorder: OutlineInputBorder(
            borderRadius: BorderRadius.circular(20),
            borderSide: const BorderSide(
              color: Colors.white,
            ),
          ),
        ),
        components: [Component(Component.country, "mx")],
      );

      displayPrediction(p);
    }

    return MaterialButton(
      onPressed: _handlePressButton,
      child: Container(
        padding: const EdgeInsets.only(left: 3, right: 3),
        child: Container(
          decoration: BoxDecoration(
              borderRadius: BorderRadius.circular(20),
              boxShadow: const [
                BoxShadow(
                  color: Colors.grey,
                  spreadRadius: 1,
                  blurRadius: 3,
                  offset: Offset(0, 3),
                ),
              ]),
          child: TextField(
            controller: _destinationController,
            decoration: InputDecoration(
              enabled: false,
              prefixIcon: const Icon(Icons.search),
              filled: true,
              fillColor: const Color(0xffEDEDED),
              hintText: 'Ingresa una nueva dirección',
              contentPadding:
                  const EdgeInsets.only(left: 14.0, bottom: 8.0, top: 8.0),
              disabledBorder: OutlineInputBorder(
                borderSide: const BorderSide(color: Colors.white),
                borderRadius: BorderRadius.circular(20),
              ),
              border: const OutlineInputBorder(),
            ),
          ),
        ),
      ),
    );
  }
}

The error are in: response.errorMessage -> The argument type 'String?' can't be assigned to the parameter type 'String' p.placeId -> The argument type 'String?' can't be assigned to the parameter type 'String'. await PlacesAutocomplete.show -> A value of type 'Prediction?' can't be assigned to a variable of type 'Prediction'. Try changing the type of the variable, or casting the right-hand type to 'Prediction'.

Any clue how to fix this?