Map selection

This example demonstrates how to explore various points of interest (POIs) and select destinations with ease.

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 map_selection directory, within the flutter examples directory - that is the name of 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:

:lineno-start: 1

    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

:lineno-start: 1

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

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

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

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

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

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

  Landmark? _focusedLandmark;

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Colors.deepPurple[900],
        title: const Text('Map Selection', style: TextStyle(color: Colors.white)),
      ),
      body: Stack(children: [
        GemMap(
          onMapCreated: _onMapCreated,
        ),
        if (_focusedLandmark != null)
          Align(
              alignment: Alignment.bottomCenter,
              child: LandmarkPanel(
                onCancelTap: _onCancelLandmarkPanelTap,
                landmark: _focusedLandmark!,
              ))
      ]),
      resizeToAvoidBottomInset: false,
    );
  }

  // The callback for when map is ready to use.
  void _onMapCreated(GemMapController controller) {
    // Save controller for further usage.
    _mapController = controller;

    // Listen for map landmark selection events.
    _registerLandmarkTapCallback();
  }

  void _registerLandmarkTapCallback() {
    _mapController.registerTouchCallback((pos) async {
      // Select the object at the tap position.
      _mapController.setCursorScreenPosition(pos);

      // Get the selected landmarks.
      final landmarks = _mapController.cursorSelectionLandmarks();

      // Check if there is a selected Landmark.
      if (landmarks.isNotEmpty) {
        // Highlight the selected landmark.
        _mapController.activateHighlight(landmarks);

        setState(() {
          _focusedLandmark = landmarks[0];
        });

        // Use the map controller to center on coordinates.
        _mapController.centerOnCoordinates(landmarks[0].coordinates);
      }
    });
  }

  void _onCancelLandmarkPanelTap() {
    // Remove landmark highlights from the map.
    _mapController.deactivateAllHighlights();

    setState(() {
      _focusedLandmark = null;
    });
  }
}

The dart material package is imported, along with the required gem_kit packages.

The selection is highlighted when it is tapped. The taps are listened to by _registerLandmarkTapCallback , which is called in the _onMapCreated() callback, executed when the interactive map is initialized and ready for use.

Flutter Examples

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