What is nearby¶
gem_kit package.
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Setup¶
Prerequisites¶
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:
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
}
}
}
Then run the project:
flutter run --debugorflutter 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¶
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This example app demonstrates the following features:
Obtain location permissions and show a map centered on the user’s location.
Display nearby landmarks as a list.
Allow navigation to a detail page displaying information about nearby landmarks.
Map Display and Permissions¶
The map is displayed and initialized within the MyHomePage widget, which also handles location permissions for Android and iOS.
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key});
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
late GemMapController _mapController;
PermissionStatus _locationPermissionStatus = PermissionStatus.denied;
bool _hasLiveDataSource = false;
@override
void dispose() {
GemKit.release();
super.dispose();
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.deepPurple[900],
title: const Text('What\'s Nearby', style: TextStyle(color: Colors.white)),
actions: [
IconButton(
onPressed: () => _onWhatIsNearbyButtonPressed(context),
icon: const Icon(Icons.question_mark, color: Colors.white),
),
],
),
body: GemMap(onMapCreated: _onMapCreated, appAuthorization: projectApiToken),
);
}
This widget handles the UI, setting up the map and app bar, and uses permission_handler for requesting location permissions.
Fetching Nearby Locations¶
The WhatIsNearbyPage widget displays a list of nearby landmarks based on the user’s current position.
class WhatIsNearbyPage extends StatefulWidget {
final Coordinates position;
const WhatIsNearbyPage({super.key, required this.position});
@override
State<WhatIsNearbyPage> createState() => _WhatIsNearbyPageState();
}
class _WhatIsNearbyPageState extends State<WhatIsNearbyPage> {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text("What's Nearby", style: TextStyle(color: Colors.white)),
backgroundColor: Colors.deepPurple[900],
),
body: FutureBuilder(
future: _getNearbyLocations(),
builder: (context, snapshot) {
if (!snapshot.hasData) {
return const Center(child: CircularProgressIndicator());
}
return ListView.separated(
itemBuilder: (context, index) => NearbyItem(
landmark: snapshot.data![index],
currentPosition: widget.position,
),
separatorBuilder: (context, index) => const Divider(height: 0),
itemCount: snapshot.data!.length,
);
},
),
);
}
Future<List<Landmark>?> _getNearbyLocations() async {
final preferences = SearchPreferences(searchAddresses: false)
..landmarkCategories = GenericCategories.categories;
final completer = Completer<List<Landmark>?>();
SearchService.searchAroundPosition(preferences: preferences, widget.position, (err, result) {
completer.complete(result);
});
return completer.future;
}
This code searches for nearby landmarks, displaying the results in a ListView.
Displaying Landmark Information¶
Each nearby landmark is displayed in a list tile showing the name and distance from the current position.
class NearbyItem extends StatefulWidget {
final Landmark landmark;
final Coordinates currentPosition;
const NearbyItem({super.key, required this.landmark, required this.currentPosition});
@override
State<NearbyItem> createState() => _NearbyItemState();
}
class _NearbyItemState extends State<NearbyItem> {
@override
Widget build(BuildContext context) {
return ListTile(
title: Text(
widget.landmark.categories.first.name,
style: const TextStyle(fontSize: 14, fontWeight: FontWeight.w400),
maxLines: 2,
overflow: TextOverflow.ellipsis,
),
trailing: Text(
_convertDistance(widget.landmark.coordinates.distance(widget.currentPosition).toInt()),
style: const TextStyle(fontSize: 14, fontWeight: FontWeight.w400),
),
);
}
String _convertDistance(int meters) {
if (meters >= 1000) {
return '${(meters / 1000).toStringAsFixed(1)} km';
} else {
return '$meters m';
}
}
This component formats and displays the name and distance of each landmark.