Flutter: How to get Name of a Place using Lat Long in Flutter Google Maps

You can use the geolocator package. Here is example code that I use, you should be able to work out your version from this:

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:geolocator/geolocator.dart';
import 'package:pedantic/pedantic.dart';
import 'package:rflutter_alert/rflutter_alert.dart';
import 'package:person/generated/i18n.dart';
import 'package:person/models/location_data.dart';
import 'package:person/scoped_models/main.dart';
import 'package:person/shared/global_config.dart' as globals;
import 'package:person/widgets/helpers/dialogue_helper.dart';
import 'package:scoped_model/scoped_model.dart';

final Geolocator _geolocator = Geolocator();
LocationData _currentLocationData;
Position _currentPosition;
String _isoCountryCode = "";

/// This method is used to get the current location of the person.
///
Future<LocationData> getCurrentLocation(
  BuildContext context, {
  Position currentPosition,
  // Will be overridden with false if called from PersonProfilePage and a new
  // user is being added.
  bool updateDatabase = true,
}) async {
  MainModel _model = ScopedModel.of(context);
  String _address = "";
  _currentLocationData = null;
  try {
    // Android shows a dialogue which automatically updates the location
    // permissions settings.
    assert(globals.configFromDatabase != null);
    // Creates a new 'location' object ie. a new instance of this class in the geoloc package
    _currentPosition = await _geolocator.getCurrentPosition(
        desiredAccuracy: globals.configFromDatabase.locationAccuracy);
    _address = await _getLocationAddress(
        _currentPosition.latitude, _currentPosition.longitude);
    _currentLocationData = LocationData(
      latitude: _currentPosition.latitude,
      longitude: _currentPosition.longitude,
      address: _address,
      isoCountryCode: _isoCountryCode,
    );
    // Update the person's current location unless this is a new
    // user being created in the PersonProfilePage. In that case the form data
    // created from this method will be used when the save button is pressed.
    if (updateDatabase) {
      assert(_currentLocationData != null);
      unawaited(_model.updateCurrentLocation(_currentLocationData));
    }
    return _currentLocationData;
  } catch (error) {
    unawaited(
      showAlertDialogue(
        <Your dialogue>
      ),
    );
    return null;
  }
}

/// This method retrieves placemark data based on a latitude and longitude
/// value pair. It then assembles the data items into an address suitable for
/// display in the app and retains the ISO3166-2 Country code in a separate
/// variable for later storage on the database against the person.
///
/// ! The Geolocator package provides this data for free so there is no need
/// ! to pay for the Google Geocoding API.
///
Future<String> _getLocationAddress(double latitude, double longitude) async {
  List<Placemark> newPlace =
      await _geolocator.placemarkFromCoordinates(latitude, longitude);
  Placemark placeMark = newPlace[0];
  String name = placeMark.name;
  // String subLocality = placeMark.subLocality;
  String locality = placeMark.locality;
  String administrativeArea = placeMark.administrativeArea;
  // String subAdministrativeArea = placeMark.administrativeArea;
  String postalCode = placeMark.postalCode;
  String country = placeMark.country;
  // String subThoroughfare = placeMark.subThoroughfare;
  String thoroughfare = placeMark.thoroughfare;
  _isoCountryCode = placeMark.isoCountryCode;
  return "$name, $thoroughfare, $locality, $administrativeArea, $postalCode, $country";
}