Flutter google map directions api

Question

I need help with google_directions_api in flutter and I tyr to create an request for get an diretions. I want to create an request for get data about my route like in google maps with step by step navigation (turn right 50m or something like this). I need help with ceating an correct request for get data

Here is one of requests which i search

Future<void> fetchCustomDirections(List<LatLng> customCoordinates) async {
    final directionsService = DirectionsService();

    final waypoints = customCoordinates
        .sublist(1, customCoordinates.length - 1)
        .map((coordinate) => DirectionsWaypoint(
              location: LatLng(coordinate.latitude, coordinate.longitude),
            ))
        .toList();

    final request = DirectionsRequest(
      origin: LatLng(
        customCoordinates.first.latitude,
        customCoordinates.first.longitude,
      ),
      destination: LatLng(
        customCoordinates.last.latitude,
        customCoordinates.last.longitude,
      ),
      alternatives: false,
      language: 'en',
      waypoints: waypoints,
    );

    final response = await directionsService.route(request, (
      DirectionsResult? response,
      DirectionsStatus? status,
    ) {
      print('Status of request: $status');

      if (status == DirectionsStatus.ok) {
        final steps = response!.routes!.first.legs!.first.steps!;
        print('Steps: $steps');
        // Update your UI with the response data
      } else {
        print('Error fetching data about route:');
      }
    });
  }

Here is my request which I want to use for my case

Future<void> fetchCustomDirections(List<LatLng> customCoordinates) async {
    final directionsService = DirectionsService();

    final waypoints = customCoordinates
        .sublist(1, customCoordinates.length - 1)
        .map((coordinate) => DirectionsWaypoint(
              location: '${coordinate.latitude},${coordinate.longitude}',
            ))
        .toList();

    final request = DirectionsRequest(
      origin: '${customCoordinates.first.latitude},${customCoordinates.first.longitude}',
      destination: '${customCoordinates.last.latitude},${customCoordinates.last.longitude}',
      alternatives: false,
      language: 'en',
      waypoints: waypoints,
    );

    final response = await directionsService.route(request, (
      DirectionsResult? response,
      DirectionsStatus? status,
    ) {
      print('Statue of request: $status');

      if (status == DirectionsStatus.ok) {
        final steps = response!.routes!.first.legs!.first.steps!;
        print('Steps: $steps');
        setState(() {
          responseData = steps.toString();
        });
      } else {
        print('Error fetching data about route:');
      }
    });
  }

And here is my request for get an directions from api

I/flutter ( 6397): Statue of request: REQUEST_DENIED

Answer 1

You must use an API_KEY for your request to work

Please see documentation for guidance in how to set-up your project and API_KEY using Directions API.

As per your given sample code, the error you have encountered is REQUEST_DENIED which is usually a client error caused by authentication error, access error, etc.

And looking at your code, you did not have DirectionsService.init('API_KEY'); at the beginning of your code block or before your final directionsService = DirectionsService();.

Doing a quick search on the google_directions_api flutter library documentation/repository will give you this sample code that shows that you need to initialize the DirectionsService with an API_KEY first like so:

import 'package:google_directions_api/google_directions_api.dart';

void main() {
  // You did not have this in your sample code
  DirectionsService.init('API_KEY');

  final directionsService = DirectionsService();

  final request = DirectionsRequest(
    origin: 'New York',
    destination: 'San Francisco',
    travelMode: TravelMode.driving,
  );

  directionsService.route(request,
      (DirectionsResult response, DirectionsStatus status) {
    if (status == DirectionsStatus.ok) {
      // do something with successful response
    } else {
      // do something with error response
    }
  });
}

I hope this helps!