Location Wikipedia

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This example demonstrates how to create a Flutter app that displays a map and retrieves Wikipedia information about selected locations using Maps SDK for Flutter. Users can explore geographic data on a map and search for relevant Wikipedia content.

How It Works

• Main App Setup : The main app initializes GemKit and sets up the primary map screen.
• Wikipedia Integration : The app enables location-based Wikipedia searches, displaying title and content of selected landmarks.

Wikipedia information retrieved for the Statue of Liberty

UI and Map Integration

The following code sets up the main screen with a map and a search button for location-based Wikipedia information.

main.dart

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

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

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

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

class _MyHomePageState extends State<MyHomePage> {
  @override
  void dispose() {
    GemKit.release();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Colors.deepPurple[900],
        title: const Text('Location Wikipedia', style: TextStyle(color: Colors.white)),
        actions: [
          IconButton(
            onPressed: () => _onLocationWikipediaTap(context),
            icon: Icon(Icons.search, color: Colors.white),
          )
        ],
      ),
      body: const GemMap(
        key: ValueKey("GemMap"),
        appAuthorization: projectApiToken,
      ),
    );
  }

  void _onLocationWikipediaTap(BuildContext context) {
    Navigator.of(context).push(MaterialPageRoute<dynamic>(
      builder: (context) => const LocationWikipediaPage(),
    ));
  }
}

Wikipedia Data Display

The following code manages the Wikipedia data retrieval and display for the selected location.

location_wikipedia_page.dart

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:gem_kit/core.dart';
import 'package:gem_kit/search.dart';

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

  @override
  State<LocationWikipediaPage> createState() => _LocationWikipediaPageState();
}

class _LocationWikipediaPageState extends State<LocationWikipediaPage> {
  @override
  void initState() {
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        automaticallyImplyLeading: true,
        foregroundColor: Colors.white,
        title: const Text(
          "Location Wikipedia",
          style: TextStyle(color: Colors.white),
        ),
        backgroundColor: Colors.deepPurple[900],
      ),
      body: FutureBuilder(
        future: _getLocationWikipedia(),
        builder: (context, snapshot) {
          if (!snapshot.hasData || snapshot.data == null) {
            return const Center(child: CircularProgressIndicator());
          }
          return Column(
            mainAxisSize: MainAxisSize.max,
            children: [
              Text(
                snapshot.data!.$1,
                style: TextStyle(
                  overflow: TextOverflow.fade,
                  fontSize: 25.0,
                  fontWeight: FontWeight.bold,
                ),
              ),
              Expanded(
                child: SingleChildScrollView(child: Text(snapshot.data!.$2)),
              ),
            ],
          );
        },
      ),
    );
  }

  Future<(String, String)> _getLocationWikipedia() async {
    final searchCompleter = Completer<List<Landmark>>();
    SearchService.search(
      "Statue of Liberty",
      Coordinates(latitude: 40.53859, longitude: -73.91619),
      (err, lmks) {
        searchCompleter.complete(lmks);
      },
    );

    final lmk = (await searchCompleter.future).first;

    if (!ExternalInfoService.hasWikiInfo(lmk)) {
      return ("Wikipedia info not available", "The landamrk does not have Wikipedia info");
    }

    final completer = Completer<ExternalInfo?>();
    ExternalInfoService.requestWikiInfo(
      lmk,
      onComplete: (err, externalInfo) => completer.complete(externalInfo),
    );

    final externalInfo = await completer.future;

    if (externalInfo == null) {
      return ("Querry failed", "The request to Wikipedia failed");
    }

    final title = externalInfo.wikiPageTitle;
    final content = externalInfo.wikiPageDescription;

    return (title, content);
  }
}