Adding polylines to Google Maps on flutter

google_maps_polyline.dart

import 'dart:async';

import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

// Starting point latitude
  double _originLatitude = 6.5212402;
// Starting point longitude
  double _originLongitude = 3.3679965;
// Destination latitude
  double _destLatitude = 6.849660;
// Destination Longitude
  double _destLongitude = 3.648190;
// Markers to show points on the map
  Map<MarkerId, Marker> markers = {}; 

  PolylinePoints polylinePoints = PolylinePoints();
  Map<PolylineId, Polyline> polylines = {};

class _MyAppState extends State<MyApp> {
  // Google Maps controller
  Completer<GoogleMapController> _controller = Completer();
  // Configure map position and zoom
  static final CameraPosition _kGooglePlex = CameraPosition(
    target: LatLng(_originLatitude, _originLongitude),
    zoom: 9.4746,
  ); 

  @override
  void initState() {
    /// add origin marker origin marker
    _addMarker(
      LatLng(_originLatitude, _originLongitude),
      "origin",
      BitmapDescriptor.defaultMarker,
    );

    // Add destination marker
    _addMarker(
      LatLng(_destLatitude, _destLongitude),
      "destination",
      BitmapDescriptor.defaultMarkerWithHue(90),
    );

    _getPolyline();

    super.initState();
  }
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Welcome to Flutter',
      home: Scaffold(
        appBar: AppBar(
          title: Text('Welcome to Flutter'),
        ),
        body: GoogleMap(
            mapType: MapType.normal,
            initialCameraPosition: _kGooglePlex,
            myLocationEnabled: true,
            tiltGesturesEnabled: true,
            compassEnabled: true,
            scrollGesturesEnabled: true,
            zoomGesturesEnabled: true,
            polylines: Set<Polyline>.of(polylines.values),
            markers: Set<Marker>.of(markers.values),
            onMapCreated: (GoogleMapController controller) {
              _controller.complete(controller);
            },
       ), 
      ),
    );
  }

  // This method will add markers to the map based on the LatLng position
  _addMarker(LatLng position, String id, BitmapDescriptor descriptor) {
    MarkerId markerId = MarkerId(id);
    Marker marker =
        Marker(markerId: markerId, icon: descriptor, position: position);
    markers[markerId] = marker;
  }

_addPolyLine(List<LatLng> polylineCoordinates) {
    PolylineId id = PolylineId("poly");
    Polyline polyline = Polyline(
      polylineId: id,
      points: polylineCoordinates,
      width: 8,
    );
    polylines[id] = polyline;
    setState(() {});
  }

void _getPolyline() async {
    List<LatLng> polylineCoordinates = [];

    PolylineResult result = await polylinePoints.getRouteBetweenCoordinates(
      "YOUR API KEY HERE",
      PointLatLng(_originLatitude, _originLongitude),
      PointLatLng(_destLatitude, _destLongitude),
      travelMode: TravelMode.driving,
    );
    if (result.points.isNotEmpty) {
      result.points.forEach((PointLatLng point) {
        polylineCoordinates.add(LatLng(point.latitude, point.longitude));
      });
    } else {
      print(result.errorMessage);
    }
    _addPolyLine(polylineCoordinates);
  }
}

When copy this code , not shown polyline between two locations, but shown only markers .

@Balaji8555 do you see any errors? And have you activated:

• Maps SDK for Android
• Maps SDK for iOS
• Directions API?

you know how i show it in flutter web, I have coordinates of two points I just want polylines like your in between the points