Search Category¶

In this guide, you will learn how to integrate map functionality and perform searches for landmarks.

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 search_category directory within the Flutter examples directory.

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

Import Necessary Packages¶

First, import the required packages in your Dart code.

import 'package:gem_kit/core.dart';
import 'package:gem_kit/map.dart';

import 'search_page.dart';

import 'package:flutter/material.dart';

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 demonstrates the following key features:

Search for landmarks based on specific categories.
Filter landmarks displayed on map by categories, making searches more targeted.

Search Category - example Flutter screenshot

Build the Main Application¶

Define the main application widget, MyApp.

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

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

Handle Map and Search Functionality¶

Create the stateful widget, MyHomePage, which will handle the map and search functionality.

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

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

Define State Variables and Methods¶

Within _MyHomePageState, define the necessary state variables and methods to manage the map and perform searches.

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("Search Category", style: TextStyle(color: Colors.white)),
        actions: [
          IconButton(
            onPressed: () => _onSearchButtonPressed(context),
            icon: const Icon(Icons.search, color: Colors.white),
          ),
        ],
      ),
      body: GemMap(
        onMapCreated: _onMapCreated,
        : projectApiToken,
      ),
    );
  }

  void _onMapCreated(GemMapController controller) {
    _mapController = controller;
  }

  // Custom method for navigating to search screen
  void _onSearchButtonPressed(BuildContext context) async {
    // Taking the coordinates at the center of the screen as reference coordinates for search.
    final x = MediaQuery.of(context).size.width / 2;
    final y = MediaQuery.of(context).size.height / 2;
    final mapCoords = _mapController.transformScreenToWgs(XyType(x: x.toInt(), y: y.toInt()));

    // Navigating to search screen. The result will be the selected search result (Landmark)
    final result = await Navigator.of(context).push(MaterialPageRoute<dynamic>(
      builder: (context) => SearchPage(
        controller: _mapController,
        coordinates: mapCoords!,
      ),
    ));

    if (result is Landmark) {
      // Activating the highlight
      _mapController.activateHighlight([result], renderSettings: HighlightRenderSettings());
      // Centering the map on the desired coordinates
      _mapController.centerOnCoordinates(result.coordinates);
    }
  }
}

Define Search Functionality¶

Implement the SearchPage widget that allows users to search for landmarks.

class SearchPage extends StatefulWidget {
  final GemMapController controller;
  final Coordinates coordinates;

  // Method to get all the generic categories
  final categories = GenericCategories.categories;

  SearchPage({super.key, required this.controller, required this.coordinates});

  @override
  State<SearchPage> createState() => _SearchPageState();
}

class _SearchPageState extends State<SearchPage> {
  final TextEditingController _textController = TextEditingController();
  List<Landmark> landmarks = [];
  List<LandmarkCategory> selectedCategories = [];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        leading: IconButton(
            onPressed: _onLeadingPressed,
            icon: const Icon(CupertinoIcons.arrow_left)),
        title: const Text("Search Category"),
        backgroundColor: Colors.deepPurple[900],
        foregroundColor: Colors.white,
        actions: [
          if (landmarks.isEmpty)
            IconButton(
                onPressed: () => _onSubmitted(_textController.text),
                icon: const Icon(Icons.search))
        ],
      ),
      body: Column(
        children: [
          if (landmarks.isEmpty)
            Padding(
              padding: const EdgeInsets.all(8.0),
              child: TextField(
                controller: _textController,
                cursorColor: Colors.deepPurple[900],
                decoration: const InputDecoration(
                  hintText: 'Enter text',
                  hintStyle: TextStyle(color: Colors.black),
                  focusedBorder: UnderlineInputBorder(
                    borderSide: BorderSide(color: Colors.deepPurple, width: 2.0),
                  ),
                ),
              ),
            ),
          if (landmarks.isEmpty)
            Expanded(
              child: ListView.separated(
                padding: EdgeInsets.zero,
                itemCount: widget.categories.length,
                controller: ScrollController(),
                separatorBuilder: (context, index) => const Divider(
                  indent: 50,
                  height: 0,
                ),
                itemBuilder: (context, index) {
                  return CategoryItem(
                    onTap: () => _onCategoryTap(index),
                    category: widget.categories[index],
                    categoryIcon: widget.categories[index].getImage(size: Size(200, 200)),
                  );
                },
              ),
            ),
          if (landmarks.isNotEmpty)
            Expanded(
              child: ListView.separated(
                padding: EdgeInsets.zero,
                itemCount: landmarks.length,
                controller: ScrollController(),
                separatorBuilder: (context, index) => const Divider(
                  indent: 50,
                  height: 0,
                ),
                itemBuilder: (context, index) {
                  final lmk = landmarks.elementAt(index);
                  return SearchResultItem(landmark: lmk);
                },
              ),
            ),
          const SizedBox(height: 5),
        ],
      ),
    );
  }

  // Search method
  Future<void> search(String text, Coordinates coordinates, SearchPreferences preferences) async {
    // Implementation of search functionality
  }

  void _onLeadingPressed() {
    // Handle back navigation
  }

  void _onCategoryTap(int index) {
    // Handle category selection
  }
}

// Class for the categories.
class CategoryItem extends StatefulWidget {
  final LandmarkCategory category;
  final Uint8List categoryIcon;
  final VoidCallback onTap;

  const CategoryItem({
    super.key,
    required this.category,
    required this.onTap,
    required this.categoryIcon
  });

  @override
  State<CategoryItem> createState() => _CategoryItemState();
}

class _CategoryItemState extends State<CategoryItem> {
  bool _isSelected = false;

  @override
  Widget build(BuildContext context) {
    return ListTile(
        onTap: () {
          widget.onTap();
          setState(() {
            _isSelected = !_isSelected;
          });
        },
        leading: Container(
          padding: const EdgeInsets.all(8),
          width: 50,
          height: 50,
          child: Image.memory(widget.categoryIcon),
        ),
        title: Text(widget.category.name,
            style: const TextStyle(color: Colors.black, fontSize: 16, fontWeight: FontWeight.w600)),
        trailing: (_isSelected)
            ? const SizedBox(
                width: 50,
                child: Icon(
                  Icons.check,
                  color: Colors.grey,
                ),
              )
            : null);
  }
}

// Class for the search results.
class SearchResultItem extends StatefulWidget {
  final Landmark landmark;

  const SearchResultItem({super.key, required this.landmark});

  @override
  State<SearchResultItem> createState() => _SearchResultItemState();
}

class _SearchResultItemState extends State<SearchResultItem> {
  @override
  Widget build(BuildContext context) {
    return ListTile(
      onTap: () => Navigator.of(context).pop(widget.landmark),
      leading: Container(
        padding: const EdgeInsets.all(8),
        width: 50,
        child: Image.memory(
          widget.landmark.getImage(),
        ),
      ),
      title: Text(
        widget.landmark.name,
        overflow: TextOverflow.fade,
        style: const TextStyle(
            color: Colors.black, fontSize: 14, fontWeight: FontWeight.w400),
        maxLines: 2,
      ),
      subtitle: Text(
        widget.landmark.getFormattedDistance() + widget.landmark.getAddress(),
        overflow: TextOverflow.ellipsis,
        style: const TextStyle(
            color: Colors.black, fontSize: 14, fontWeight: FontWeight.w400),
      ),
    );
  }
}

Flutter Examples¶

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