Human Voices

This example demonstrates the functionalities of the map SDK, including route calculation, simulation of navigation, and voice instructions.

Setup

First, get an API key token, see the Getting Started guide.

Prerequisites

Make sure you completed the Environment Setup - Flutter Examples guide before starting this guide.

Build and Run

Go to the human_voices directory within the Flutter examples directory. This is the directory name for this example project.

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:

Android

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:

allprojects {
    repositories {
        google()
        mavenCentral()
        maven {
           url "${rootDir}/../plugins/gem_kit/android/build"
        }
    }
}

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

android {
    defaultConfig {
        applicationId "com.magiclane.gem_kit.examples.example_pathname"
        minSdk 21
        targetSdk flutter.targetSdk
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
    }
    buildTypes {
        release {
            minifyEnabled false
            shrinkResources false

            // TODO: Add your own signing config for the release build.
            // Signing with the debug keys for now, so `flutter run --release` works.
            signingConfig signingConfigs.debug
        }
    }
}

iOS

In the ios/Podfile configuration file, at the top, set the minimum ios platform version to 14 like this:

platform :ios, '14.0'

We recommend you to run these commands after you copy the gem_kit into your project: | flutter clean | flutter pub get | and | cd ios | pod install

Then run the project:

flutter run --debug

or

flutter run --release

App entry and initialization

const projectApiToken = String.fromEnvironment('GEM_TOKEN');

void main() {
  runApp(const MyApp());
}

This code initializes the projectApiToken with the required authorization token and launches the app.

How It Works

This example integrates several components to simulate navigation with voice instructions. Here’s a breakdown of the key functionalities:

• Calculate routes based on user-defined landmarks and route preferences.

• Simulate navigation along a calculated route with real-time text-to-speech (TTS) instructions.

• Display and center routes on the map, with the camera following the simulated position.

Route Calculation

The user can trigger route calculation, which involves defining landmarks and preferences, then using RoutingService.calculateRoute to compute the route.

:lineno-start: 1

void _onBuildRouteButtonPressed(BuildContext context) {
  _showSnackBar(context, message: 'The route is calculating.');

  // Define landmarks.
  final departureLandmark =
      Landmark.withLatLng(latitude: 48.87586, longitude: 2.30311);
  final intermediaryPointLandmark =
      Landmark.withLatLng(latitude: 48.87422, longitude: 2.29952);
  final destinationLandmark =
      Landmark.withLatLng(latitude: 48.87361, longitude: 2.29513);

  // Define the route preferences.
  final routePreferences = RoutePreferences();

  // Calculate the route.
  _routingHandler = RoutingService.calculateRoute(
      [departureLandmark, intermediaryPointLandmark, destinationLandmark],
      routePreferences, (err, routes) {
    _routingHandler = null;
    ScaffoldMessenger.of(context).clearSnackBars();

    if (err == GemError.success) {
      final routesMap = _mapController.preferences.routes;
      for (final route in routes!) {
        routesMap.add(route, route == routes.first,
            label: route.getMapLabel());
      }
      _mapController.centerOnRoutes(routes: routes);
      setState(() => _areRoutesBuilt = true);
    }
  });
}

Simulated Navigation

Once the route is built, the user can start the navigation simulation. The simulation triggers text-to-speech (TTS) instructions using the TTSEngine class.

:lineno-start: 1

void _startSimulation() {
  final routes = _mapController.preferences.routes;

  _navigationHandler = NavigationService.startSimulation(routes.mainRoute,
      (type, instruction) async {
    if (type == NavigationEventType.destinationReached ||
        type == NavigationEventType.error) {
      setState(() {
        _isSimulationActive = false;
        _cancelRoute();
      });
      return;
    }
    _isSimulationActive = true;
    if (instruction != null) {
      setState(() => currentInstruction = instruction);
    }
  }, onTextToSpeechInstruction: (textInstruction) {
    _ttsEngine.speakText(textInstruction);
  }, speedMultiplier: 20);

  _mapController.startFollowingPosition();
}

The onTextToSpeechInstruction: callback receives the TTS instructions, which are then spoken using the TTSEngine .

The camera follows the simulated position as the simulation progresses.

UI Components

The example includes custom UI components, such as NavigationInstructionPanel and NavigationBottomPanel , to display navigation instructions and other relevant details during the simulation.

Flutter Examples

Maps SDK for Flutter Examples can be downloaded or cloned with Git