How to Draw Route Direction Polylines on Google Map in Flutter
Introduction
———-
In today’s world, navigation and mapping have become an essential part of our daily lives. With the increasing need for mobile applications that can provide accurate and real-time navigation, many developers have turned to Google Maps. However, there is a huge demand for customizing Google Maps in mobile applications to meet the specific needs of various businesses and individuals. This leads to the requirement of drawing route direction polylines on Google Maps in Flutter, a popular cross-platform development framework. In this article, we will explore how to draw route direction polylines on Google Maps in Flutter, including the necessary setup, code, and practical examples.
Setting up Google Maps in Flutter
Before we start drawing route direction polylines on Google Maps, we need to set up Google Maps in Flutter. Follow these steps to set up Google Maps in your Flutter project:
Step 1: Add Google Maps Provider
To use Google Maps in Flutter, you need to add the Google Maps provider to your project. You can do this by running the following command in your terminal:
“`bash
flutter pub add googlemapsflutter
“`
Step 2: Import Necessary Packages
Now that you have added the Google Maps provider, you need to import the necessary packages in your Flutter project. Add the following imports to your project:
“`dart
import ‘package:flutter/material.dart’;
import ‘package:googlemapsflutter/googlemapsflutter.dart’;
“`
Step 3: Set up Google Maps in Your Flutter Widget
To set up Google Maps in your Flutter widget, you can use the GoogleMap widget provided by the Google Maps provider. Here is an example of how you can use the GoogleMap widget:
“`dart
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
home: MapScreen(),
);
}
}
class MapScreen extends StatefulWidget {
@override
MapScreenState createState() => MapScreenState();
}
class _MapScreenState extends State
final GoogleMapController _mapController = GoogleMapController();
@override
Widget build(BuildContext context) {
return Scaffold(
body: GoogleMap(
onMapCreated: (GoogleMapController controller) {
_mapController = controller;
},
initialCameraPosition: CameraPosition(
target: LatLng(37.7749, -122.4194),
zoom: 12,
),
),
);
}
}
“`
Drawing Route Direction Polylines on Google Maps
Now that we have set up Google Maps in Flutter, we can proceed to draw route direction polylines on Google Maps.
Step 1: Get the Route Direction Polylines
To draw route direction polylines on Google Maps, you first need to get the route direction polylines. You can use the Google Maps Directions API to get the route direction polylines. Here is an example of how you can use the Google Maps Directions API:
“`dart
class _MapScreenState extends State
List
String origin = ‘37.7749,-122.4194’;
String destination = ‘37.8024,-122.4056’;
@override
void initState() {
super.initState();
setState(() {
_getRouteDirectionPolylines();
});
}
Future
final response = await http.get(Uri.https(‘maps.googleapis.com’, ‘/maps/api/directions/json’)
..queryParameters = {
‘origin’: origin,
‘destination’: destination,
‘mode’: ‘driving’,
‘key’: ‘YOURGOOGLEMAPSAPIKEY’,
});
final jsonresponse = jsonDecode(response.body);
final routeOverviews = jsonresponse[‘routes’];
setState(() {
polylinePoints = [];
for (final routeOverview in routeOverviews) {
final polylinePointsList = routeOverview[‘legs’][0][‘steps’];
for (final polylinePoints in polylinePointsList) {
polylinePoints.add(LatLng(polylinePoints[‘endlocation’][‘lat’], polylinePoints[‘endlocation’][‘lng’]));
}
}
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: GoogleMap(
markers: {
Marker(
markerId: MarkerId(‘Origin Marker’),
position: LatLng(37.7749, -122.4194),
icon: BitmapDescriptor.defaultMarker,
),
Marker(
markerId: MarkerId(‘Destination Marker’),
position: LatLng(37.8024, -122.4056),
icon: BitmapDescriptor.defaultMarker,
),
},
polylines: {
Polyline(
polylineId: PolylineId(‘Route Direction Polylines’),
points: polylinePoints,
color: Colors.blue,
width: 5,
),
},
onMapCreated: (GoogleMapController controller) {
_mapController = controller;
},
initialCameraPosition: CameraPosition(
target: LatLng(37.7749, -122.4194),
zoom: 12,
),
),
);
}
}
“`
Conclusion
In this article, we explored how to draw route direction polylines on Google Maps in Flutter. We first set up Google Maps in our Flutter project and then drew route direction polylines using the Google Maps Directions API.
Future Improvements
To further improve this code, you can consider the following:
- Use a real-time map that updates the map location of the polyline as the user moves.
- Use a cached polyline points to improve performance when drawing the polyline.
- Add a loading indicator to display while fetching and parsing the route direction polylines.
FAQ
1. Q: How to use Google Maps Directions API in Flutter?
A: You can use the Google Maps Directions API to get the route direction polylines by making a GET request to the Google Maps Directions API endpoint.
2. Q: How to draw polyline on Google Maps in Flutter?
A: You can draw a polyline on Google Maps in Flutter by using the Polyline widget provided by the Google Maps provider.
3. Q: What is the Google Maps Directions API?
A: The Google Maps Directions API is a service provided by Google Maps that returns directions between locations, along with the route and other information.
4. Q: How to get the Google Maps API key?
A: You can get the Google Maps API key by creating a project in the Google Cloud Console and enabling the Google Maps API.
5. Q: How to update the map location of the polyline as the user moves?
A: You can update the map location of the polyline as the user moves by fetching the new location of the user and updating the polyline points accordingly.
By following this guide, you can successfully draw route direction polylines on Google Maps in your Flutter project, which will allow your users to easily navigate to their desired location.
