In this article, we will explore the Moving Marker Using Polyline On Google Maps In Flutter. We see how to execute a demo program. We will tell you the best way how to move markers from one location to another location using polyline on Google Maps in your Flutter applications.

• For Google Maps Flutter:

google_maps_flutter | Flutter package
A Flutter plugin for integrating Google Maps in iOS and Android applications.pub.dev

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Table Of Contents::

Introduction

Implementation

Code Implement

Code File

Conclusion

Introduction:

The below demo video shows how to create a moving marker On Google Maps in Flutter and how a moving marker will work on Google Maps using polyline in your Flutter applications. We will create a marker they will move from one location to another location on Google Maps using polyline. It will be shown on your device.

Demo Module::

Implementation:

Step 1: Add the dependencies

Add dependencies to pubspec — yaml file.

dependencies:
flutter:
sdk: flutter
google_maps_flutter: ^2.5.2

Step 2: Import

import 'package:google_maps_flutter/google_maps_flutter.dart';

Step 3: Run flutter packages get in the root directory of your app.

Step 4: Update the build.gradle File

Set the minSdkVersion in android/app/build.gradle:

android {
defaultConfig {
minSdkVersion 20
}
}

Step 5: Add API Key

• For Andriod:

Add the Api key in android/app/src/main/AndroidManifest.xml:

<manifest ...
<application ...
<meta-data
android:name="com.google.android.geo.API_KEY"
android:value="YOUR_API_KEY_HERE"/>
</application>
</manifest>

• For Ios:

To set up, specify your API key in the application delegate ios/Runner/AppDelegate.m:

import GoogleMaps
...
GMSServices.provideAPIKey("YOUR_API_KEY_HERE")

How to implement code in dart file :

You need to implement it in your code respectively:

Create a new dart file called main.dart inside the lib folder.

In the main .dart file. We will create a new class MyHomePage(). In this class, we will define a GoogleMapControlle:r as a mapController variable and Set Polylines as a polylines variable ie equal to a curly bracket.GoogleMapController? mapController;
Set<Polyline> polylines = {};

Now, we will set the marker variable was markers are equal to the Set(). Also, we will add an initial current location was available loc1 is equal to the LatLng(). Set<Marker> markers = Set();
LatLng loc1 = const LatLng(28.612898, 77.365930);

Then, we will add the two position variables pos1 and pos2 of the polylines.

• late LatLng pos1;
• late LatLng pos2;

Now, we will add the initState() method. In this method, we will add the initial position of the moving marker was the position is equal to loc1.latitude, loc1.longitude in square bracket. Also, the pos1 and pos2 variable is equal to the loc1. in this method, we will add the addMarkers() method. We will define the below code.

@override
void initState() {
position = [
loc1.latitude,
loc1.longitude
]; //initial position of moving marker
pos1 = loc1;
pos2 = loc1;
addMarkers();
super.initState();
}

We will create the addMarkers() method. In this method, we will add marderId, position, and icon.

addMarkers() async {
markers.add(Marker(
markerId: MarkerId(loc1.toString()),
position: loc1,
icon: BitmapDescriptor.defaultMarker));
setState(() {
});
}

We will create an animation() method. In this method, start the moving marker. Another, method we will create is movingMarker(). We will dine the below code.

animation(result) {
i = 0;
deltaLat = (result[0] - position[0]) / numDeltas;
deltaLng = (result[1] - position[1]) / numDeltas;
movingMarker();
}
movingMarker() {
position[0] += deltaLat;
position[1] += deltaLng;
var latlng = LatLng(position[0], position[1]);

markers = {
Marker(
markerId: const MarkerId("moving marker"),
position: latlng,
icon: BitmapDescriptor.defaultMarker,
)
};

pos1 = pos2;
pos2 = LatLng(position[0], position[1]);

polylines.add(Polyline(
polylineId: PolylineId(pos2.toString()),
visible: true,
width: 5,
//width of polyline
points: [
pos1,
pos2,
],
color: Colors.blue, //color of polyline
));

setState(() {
});

if (i != numDeltas) {
i++;
Future.delayed(Duration(milliseconds: delay), () {
movingMarker();
});
}
}

In the body part, we will add the GoogleMap() method. In this method, we will add zoomGesturesEnabled was true, set the initialCameraPosition as zoom is 14, and the target was your loc1 wrap to CameraPosition(), add variable on polylines, map type was normal.

GoogleMap(
zoomGesturesEnabled: true,
initialCameraPosition: CameraPosition(
target: loc1,
zoom: 14.0,
),
markers: markers,
polylines: polylines,
mapType: MapType.normal,
onMapCreated: (controller) {
//method called when map is created
setState(() {
mapController = controller;
});
},
)

onMapCreated was this method called when a map is created. Inside onMapCreated, we will add the setState() function. In this function, we will add mapController is equal to the controller. We will add the variable markers on markers.

Now, we will create a FloatingActionButton(). In this button, we will add backgroundColor was red.shade300, its child adds the text “Start Moving”.

floatingActionButton: SizedBox(
height: MediaQuery.of(context).size.height * 0.3,
width: MediaQuery.of(context).size.width * 0.175,
child: FloatingActionButton(
backgroundColor: Colors.red.shade300,
child: const Center(
child: Text(
"Start\nMoving",
textAlign: TextAlign.center,
)),
onPressed: () {
var result = [28.6279, 77.3749];
animation(result);
},
),
),

onPressed we will add the latitude and longitude of the new position if was var result is equal to the [28.6279, 77.3749] also add animation(result) for the start moving marker.

When we run the application, we ought to get the screen’s output like the underneath screen capture.

Code File:

import 'package:flutter/material.dart';
import 'package:flutter_polylines_moving_marker_demo/splash_screen.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
void main() {
runApp(const MyApp());
}

class MyApp extends StatelessWidget {
const MyApp({super.key});

@override
Widget build(BuildContext context) {
return const MaterialApp(
debugShowCheckedModeBanner: false,
home: Splash(),
);
}
}

class MyHomePage extends StatefulWidget {
const MyHomePage({super.key});

@override
_MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
GoogleMapController? mapController;
Set<Polyline> polylines = {};

Set<Marker> markers = Set();

LatLng loc1 = const LatLng(28.612898, 77.365930);

int numDeltas = 40;
int delay = 40;
var i = 0;
double? deltaLat;
double? deltaLng;
var position;

late LatLng pos1;
late LatLng pos2;

@override
void initState() {
position = [loc1.latitude, loc1.longitude];
pos1 = loc1;
pos2 = loc1;
addMarkers();
super.initState();
}

addMarkers() async {
markers.add(Marker(
markerId: MarkerId(loc1.toString()),
position: loc1,
icon: BitmapDescriptor.defaultMarker));

setState(() {});
}

animation(result) {
i = 0;
deltaLat = (result[0] - position[0]) / numDeltas;
deltaLng = (result[1] - position[1]) / numDeltas;
movingMarker();
}

movingMarker() {
position[0] += deltaLat;
position[1] += deltaLng;
var latlng = LatLng(position[0], position[1]);

markers = {
Marker(
markerId: const MarkerId("moving marker"),
position: latlng,
icon: BitmapDescriptor.defaultMarker,
)
};

pos1 = pos2;
pos2 = LatLng(position[0], position[1]);

polylines.add(Polyline(
polylineId: PolylineId(pos2.toString()),
visible: true,
width: 5,
//width of polyline
points: [
pos1,
pos2,
],
color: Colors.blue, //color of polyline
));

setState(() {
//refresh UI
});

if (i != numDeltas) {
i++;
Future.delayed(Duration(milliseconds: delay), () {
movingMarker();
});
}
}

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
automaticallyImplyLeading: false,
title: const Text(
"Flutter Moving Marker Using Polylines",
),
backgroundColor: Colors.red.shade300,
),
floatingActionButton: SizedBox(
height: MediaQuery.of(context).size.height * 0.3,
width: MediaQuery.of(context).size.width * 0.175,
child: FloatingActionButton(
backgroundColor: Colors.red.shade300,
child: const Center(
child: Text(
"Start\nMoving",
textAlign: TextAlign.center,
)),
onPressed: () {
var result = [28.6279, 77.3749];

animation(result);
},
),
),
body: GoogleMap(
zoomGesturesEnabled: true,
initialCameraPosition: CameraPosition(
target: loc1,
zoom: 14.0,
),
markers: markers,
polylines: polylines,
mapType: MapType.normal,
onMapCreated: (controller) {
setState(() {
mapController = controller;
});
},
));
}
}

Conclusion:

In the article, I have explained the Moving Marker Using Polyline On Google Maps In Flutter; you can modify this code according to your choice. This was a small introduction to the Moving Marker Using Polyline On Google Maps In Flutter User Interaction from my side, and it’s working using Flutter.

I hope this blog will provide you with sufficient information on Trying Moving Marker Using Polyline On Google Maps in your Flutter projects. We will show you what the Introduction is. Make a demo program for working on moving marker using polyline on Google Maps to show marker was moving from one location to another location using polyline and also draw a line in your Flutter applications. So please try it.

❤ ❤ Thanks for reading this article ❤❤

If I need to correct something? Let me know in the comments. I would love to improve.

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