Map Gestures

This example demonstrates how to create a Flutter app that enables map gesture interactions using GemKit.

Users can interact with the map using gestures such as touch, move, angle change, and long press.

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

Navigate to the project folder for this example to build and run the application.

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:

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    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

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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

1. Main App Setup: The main app initializes GemKit and displays a map.

2. Map Gesture Handlers: Various gesture callbacks are registered on the map to track user interactions, including touch, movement, angle changes, and long presses.

User Interface

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

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Map Gestures',
      home: MyHomePage(),
    );
  }
}

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

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

Map Gesture Interactions

class _MyHomePageState extends State<MyHomePage> {
  late GemMapController _mapController;

  @override
  void dispose() {
    GemKit.release();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Colors.deepPurple[900],
        title: const Text('Map Gestures', style: TextStyle(color: Colors.white)),
      ),
      body: GemMap(onMapCreated: _onMapCreated, appAuthorization: projectApiToken),
    );
  }

  void _onMapCreated(GemMapController controller) {
    _mapController = controller;

    _mapController.registerOnMapAngleUpdate((angle) {
      print("Gesture: onMapAngleUpdate $angle");
    });

    _mapController.registerTouchCallback((point) {
      print("Gesture: onTouch $point");
    });

    _mapController.registerMoveCallback((point1, point2) {
      print('Gesture: onMove from (${point1.x} ${point1.y}) to (${point2.x} ${point2.y})');
    });

    _mapController.registerOnLongPressCallback((point) {
      print('Gesture: onLongPress $point');
    });
  }
}

This code sets up the main screen with a map and registers gesture handlers to print updates to the console based on user interactions.

Gesture Callbacks

Each of the following callbacks listens to a different type of map interaction:

• registerOnMapAngleUpdate: Monitors angle changes when the map rotates.

• registerTouchCallback: Detects touch interactions on the map.

• registerMoveCallback: Tracks the movement from one point to another on the map.

• registerOnLongPressCallback: Detects long-press gestures on the map.

Flutter Examples

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