Finger Route¶
Setup¶
Prerequisites¶
Build and Run¶
Navigate to the finger_route
directory within the Flutter examples directory. This is the project folder for this example.
Note - the gem_kit
directory containing the Maps SDK for Flutter
should be in the plugins
directory of the example, e.g.
example_pathname/plugins/gem_kit
- see the environment setup guide above.
Run: flutter pub get
Configure the native parts:
First, verify that the ANDROID_SDK_ROOT
environment variable
is set to the root path of your android SDK.
In android/build.gradle
add the maven
block as shown,
within the allprojects
block, for both debug and release builds:
1 allprojects {
2 repositories {
3 google()
4 mavenCentral()
5 maven {
6 url "${rootDir}/../plugins/gem_kit/android/build"
7 }
8 }
9 }
in android/app/build.gradle
within the android
block, in the defaultConfig
block,
the android SDK version minSdk
must be set as shown below.
Additionally, for release builds, in android/app/build.gradle
,
within the android
block, add the buildTypes
block as shown:
Replace example_pathname
with the actual project pathname
1android {
2 defaultConfig {
3 applicationId "com.magiclane.gem_kit.examples.example_pathname"
4 minSdk 21
5 targetSdk flutter.targetSdk
6 versionCode flutterVersionCode.toInteger()
7 versionName flutterVersionName
8 }
9 buildTypes {
10 release {
11 minifyEnabled false
12 shrinkResources false
13
14 // TODO: Add your own signing config for the release build.
15 // Signing with the debug keys for now, so `flutter run --release` works.
16 signingConfig signingConfigs.debug
17 }
18 }
19}
Then run the project:
flutter run --debug
orflutter run --release
How It Works¶
The example app demonstrates the following features:
Allow users to draw a route on the map with their finger.
Calculate a route based on the drawn waypoints.
Display the route on a map and provide options to cancel or clear the routes.
1import 'package:gem_kit/core.dart';
2import 'package:gem_kit/map.dart';
3import 'package:gem_kit/routing.dart';
4import 'package:flutter/cupertino.dart' hide Route;
5import 'package:flutter/material.dart' hide Route;
6
7Future<void> main() async {
8 const projectApiToken = String.fromEnvironment('GEM_TOKEN');
9
10 await GemKit.initialize(appAuthorization: projectApiToken);
11
12 runApp(const MyApp());
13}
This imports the necessary packages, initializes GemKit, and sets up the main entry point of the app.
UI and Map Integration¶
1class MyApp extends StatelessWidget {
2 const MyApp({super.key});
3
4 @override
5 Widget build(BuildContext context) {
6 return const MaterialApp(
7 debugShowCheckedModeBanner: false,
8 title: 'Finger Route',
9 home: MyHomePage(),
10 );
11 }
12}
13
14class MyHomePage extends StatefulWidget {
15 const MyHomePage({super.key});
16
17 @override
18 State<MyHomePage> createState() => _MyHomePageState();
19}
20
21class _MyHomePageState extends State<MyHomePage> {
22 late GemMapController _mapController;
23
24 TaskHandler? _routingHandler;
25 bool _areRoutesBuilt = false;
26 bool _isInDrawingMode = false;
27
28 @override
29 void dispose() {
30 GemKit.release();
31 super.dispose();
32 }
33
34 @override
35 Widget build(BuildContext context) {
36 return Scaffold(
37 appBar: AppBar(
38 backgroundColor: Colors.deepPurple[900],
39 title: const Text('Finger Route', style: TextStyle(color: Colors.white)),
40 actions: [
41 // Enable drawing mode.
42 if (_routingHandler == null && !_areRoutesBuilt && !_isInDrawingMode)
43 IconButton(
44 onPressed: () => _onDrawPressed(),
45 icon: const Icon(CupertinoIcons.hand_draw, color: Colors.white),
46 ),
47 // Build route from drawn waypoints.
48 if (_routingHandler == null && !_areRoutesBuilt && _isInDrawingMode)
49 IconButton(
50 onPressed: () => _onBuildRouteButtonPressed(context),
51 icon: const Icon(Icons.done, color: Colors.white),
52 ),
53 // Cancel route calculation.
54 if (_routingHandler != null)
55 IconButton(
56 onPressed: () => _onCancelRouteButtonPressed(),
57 icon: const Icon(Icons.stop, color: Colors.white),
58 ),
59 // Clear the drawn routes.
60 if (_areRoutesBuilt)
61 IconButton(
62 onPressed: () => _onClearRoutesButtonPressed(),
63 icon: const Icon(Icons.clear, color: Colors.white),
64 ),
65 ],
66 ),
67 body: GemMap(
68 onMapCreated: _onMapCreated,
69 ),
70 );
71 }
This code sets up the basic structure of the app, including the map and the app bar. It also provides buttons in the app bar for drawing, building, canceling, and clearing routes.
Drawing and Route Calculation¶
1// The callback for when the map is ready to use.
2void _onMapCreated(GemMapController controller) {
3 // Save controller for further usage.
4 _mapController = controller;
5}
6
7void _onDrawPressed() {
8 _mapController.enableDrawMarkersMode();
9 setState(() {
10 _isInDrawingMode = true;
11 });
12}
13
14void _onBuildRouteButtonPressed(BuildContext context) {
15 final waypoints = _mapController.disableDrawMarkersMode();
16
17 // Define the route preferences.
18 final routePreferences = RoutePreferences(
19 accurateTrackMatch: false, ignoreRestrictionsOverTrack: true);
20
21 _showSnackBar(context, message: "The route is being calculated.");
22
23 _routingHandler = RoutingService.calculateRoute(waypoints, routePreferences,
24 (err, routes) {
25 setState(() {
26 _routingHandler = null;
27 _isInDrawingMode = false;
28 });
29
30 ScaffoldMessenger.of(context).clearSnackBars();
31
32 if (err == GemError.success) {
33 final routesMap = _mapController.preferences.routes;
34
35 for (final route in routes!) {
36 routesMap.add(route, route == routes.first,
37 label: route.getMapLabel());
38 }
39
40 _mapController.centerOnRoutes(routes: routes);
41 setState(() {
42 _areRoutesBuilt = true;
43 });
44 }
45 });
46
47 setState(() {});
48}
49
50void _onClearRoutesButtonPressed() {
51 // Remove the routes from map.
52 _mapController.preferences.routes.clear();
53
54 setState(() {
55 _areRoutesBuilt = false;
56 });
57}
58
59void _onCancelRouteButtonPressed() {
60 // If we have a progress listener, cancel the route calculation.
61 if (_routingHandler != null) {
62 RoutingService.cancelRoute(_routingHandler!);
63
64 setState(() {
65 _routingHandler = null;
66 });
67 }
68}
This code handles drawing waypoints on the map, calculating the route based on those waypoints, and provides options to cancel or clear the routes. The map is centered on the calculated routes, and a label showing the distance and duration is displayed.
Displaying Route Information¶
1// Define an extension for route for calculating the route label which will be displayed on map.
2extension RouteExtension on Route {
3 String getMapLabel() {
4 final totalDistance = getTimeDistance().unrestrictedDistanceM +
5 getTimeDistance().restrictedDistanceM;
6 final totalDuration =
7 getTimeDistance().unrestrictedTimeS + getTimeDistance().restrictedTimeS;
8
9 return '${_convertDistance(totalDistance)} \n${_convertDuration(totalDuration)}';
10 }
11
12 // Utility function to convert the meters distance into a suitable format.
13 String _convertDistance(int meters) {
14 if (meters >= 1000) {
15 double kilometers = meters / 1000;
16 return '${kilometers.toStringAsFixed(1)} km';
17 } else {
18 return '${meters.toString()} m';
19 }
20 }
21
22 // Utility function to convert the seconds duration into a suitable format.
23 String _convertDuration(int seconds) {
24 int hours = seconds ~/ 3600; // Number of whole hours
25 int minutes = (seconds % 3600) ~/ 60; // Number of whole minutes
26
27 String hoursText = (hours > 0) ? '$hours h ' : ''; // Hours text
28 String minutesText = '$minutes min'; // Minutes text
29
30 return hoursText + minutesText;
31 }
32}
This code defines an extension on the Route
class that calculates and formats the distance and duration of the route for display on the map.