google_maps_flutter_heatmap

Google Maps for Flutter (Developers Preview)

A Flutter plugin that provides a Google Maps widget with heatmap support.

Developers Preview Status

The plugin relies on Flutter's new mechanism for embedding Android and iOS views. As that mechanism is currently in a developers preview, this plugin should also be considered a developers preview.

Known issues are tagged with the platform-views and/or maps labels.

To use this plugin on iOS you need to opt-in for the embedded views preview by adding a boolean property to the app's Info.plist file, with the key io.flutter.embedded_views_preview and the value YES.

The API exposed by this plugin is not yet stable, and we expect some breaking changes to land soon.

Usage

To use this plugin, add google_maps_flutter_heatmap as a dependency in your pubspec.yaml file.

Getting Started

Get an API key at https://cloud.google.com/maps-platform/.

Android

Specify your API key in the application manifest android/app/src/main/AndroidManifest.xml:

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

iOS

Specify your API key in the application delegate ios/Runner/AppDelegate.m:

#include "AppDelegate.h"
#include "GeneratedPluginRegistrant.h"
#import "GoogleMaps/GoogleMaps.h"

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application
    didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
  [GMSServices provideAPIKey:@"YOUR KEY HERE"];
  [GeneratedPluginRegistrant registerWithRegistry:self];
  return [super application:application didFinishLaunchingWithOptions:launchOptions];
}
@end

Or in your swift code, specify your API key in the application delegate ios/Runner/AppDelegate.swift:

import UIKit
import Flutter
import GoogleMaps

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?
  ) -> Bool {
    GMSServices.provideAPIKey("YOUR KEY HERE")
    GeneratedPluginRegistrant.register(with: self)
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
}

Opt-in to the embedded views preview by adding a boolean property to the app's Info.plist file with the key io.flutter.embedded_views_preview and the value YES.

Both

You can now add a GoogleMap widget to your widget tree.

The map view can be controlled with the GoogleMapController that is passed to the GoogleMap's onMapCreated callback.

Sample Usage

import 'dart:async';

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Google Maps Demo',
      home: MapSample(),
    );
  }
}

class MapSample extends StatefulWidget {
  @override
  State<MapSample> createState() => MapSampleState();
}

class MapSampleState extends State<MapSample> {
  Completer<GoogleMapController> _controller = Completer();
  final Set<Heatmap> _heatmaps = {};
  static final CameraPosition _kGooglePlex = CameraPosition(
    target: LatLng(37.42796133580664, -122.085749655962),
    zoom: 14.4746,
  );
  LatLng _heatmapLocation = LatLng(37.42796133580664, -122.085749655962);
  static final CameraPosition _kLake = CameraPosition(
      bearing: 192.8334901395799,
      target: LatLng(37.43296265331129, -122.08832357078792),
      tilt: 59.440717697143555,
      zoom: 19.151926040649414);

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      body: GoogleMap(
        mapType: MapType.hybrid,
        initialCameraPosition: _kGooglePlex,
        heatmaps: _heatmaps,
        onMapCreated: (GoogleMapController controller) {
          _controller.complete(controller);
        },
      ),
      floatingActionButton: FloatingActionButton.extended(
        onPressed: _goToTheLake,
        label: Text('To the lake!'),
        icon: Icon(Icons.directions_boat),
      ),
      floatingActionButton: FloatingActionButton.extended(
        onPressed: _addHeatmap,
        label: Text('Add Heatmap'),
        icon: Icon(Icons.add_box),
      ),
    );
  }
  void _addHeatmap(){
    setState(() {
      _heatmaps.add(
        Heatmap(
          heatmapId: HeatmapId(_heatmapLocation.toString()),
          points: _createPoints(_heatmapLocation),
          radius: 20,
          visible: true,
          gradient:  HeatmapGradient(
            colors: <Color>[Colors.green, Colors.red], startPoints: <double>[0.2, 0.8]
          )
        )
      );
    });
  }
  //heatmap generation helper functions
  List<WeightedLatLng> _createPoints(LatLng location) {
    final List<WeightedLatLng> points = <WeightedLatLng>[];
    //Can create multiple points here
    points.add(_createWeightedLatLng(location.latitude,location.longitude, 1));
    points.add(_createWeightedLatLng(location.latitude-1,location.longitude, 1)); 
    return points;
  }

  WeightedLatLng _createWeightedLatLng(double lat, double lng, int weight) {
    return WeightedLatLng(point: LatLng(lat, lng), intensity: weight);
  }

  Future<void> _goToTheLake() async {
    final GoogleMapController controller = await _controller.future;
    controller.animateCamera(CameraUpdate.newCameraPosition(_kLake));
  }
}

See the example directory for a complete sample app.