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Hello Map

In this example, you will learn how to render an interactive map using the GemKit package in Flutter.

hello_map - example flutter screenshot

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 hello_map 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. Replace example_pathname with the actual example path name, such as address_search

Download project dependencies:

example flutter upgrade screenshot

flutter upgrade

example flutter clean screenshot

run the following terminal commands in the project directory, where the pubspec.yaml file is located:

flutter clean

example flutter pub get screenshot

flutter pub get

Run the example:

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, without the line numbers, those are for reference:

1allprojects {
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 example pathname, such as center_coordinates

 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
or
flutter run --release

In the ios/Podfile configuration text file, at the top, set the minimum ios platform to 13 like this:

platform :ios, '13.0'

Then run the project:

flutter run --debug
or
flutter run --release

How It Works

The following code demonstrates the main components of the “Hello Map” example:

 1import 'package:flutter/material.dart';
 2import 'package:gem_kit/core.dart';
 3import 'package:gem_kit/map.dart';
 4
 5Future<void> main() async {
 6  const projectApiToken = String.fromEnvironment('GEM_TOKEN');
 7
 8  await GemKit.initialize(appAuthorization: projectApiToken);
 9
10  runApp(const MyApp());
11}
12
13class MyApp extends StatelessWidget {
14  const MyApp({super.key});
15
16  @override
17  Widget build(BuildContext context) {
18    return const MaterialApp(
19      debugShowCheckedModeBanner: false,
20      title: 'Hello Map',
21      home: MyHomePage(),
22    );
23  }
24}

In the above code, the MaterialApp is initialized with the GemKit authorization token. The main widget, MyApp, serves as the root of the application, which will display the interactive map.

Map Display and Clean Up

The following code outlines the main page widget, which displays the map and handles resource clean-up:

 1class MyHomePage extends StatefulWidget {
 2  const MyHomePage({super.key});
 3
 4  @override
 5  State<MyHomePage> createState() => _MyHomePageState();
 6}
 7
 8class _MyHomePageState extends State<MyHomePage> {
 9  @override
10  void dispose() {
11    GemKit.release();
12    super.dispose();
13  }
14
15  @override
16  Widget build(BuildContext context) {
17    return Scaffold(
18      appBar: AppBar(
19        backgroundColor: Colors.deepPurple[900],
20        title: const Text('Hello Map', style: TextStyle(color: Colors.white)),
21      ),
22      body: const GemMap(),
23    );
24  }
25}
The MyHomePage widget contains the scaffold that houses the map.
The dispose method ensures that resources are released when the widget is destroyed.
The GemMap() widget is used to display the interactive map in the body of the scaffold.

Flutter Examples

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