title: Flutter - Map blank in device Android
body: <p>I'm trying to show a map in my app made with flutter, I'm using this Widget: <a href="https://github.com/johnpryan/flutter_map" rel="nofollow noreferrer">flutter_map</a>.</p>
  
  <p>When I test my app in emulator, all works fine:</p>
  
  <p><a href="https://i.stack.imgur.com/42WF2.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/42WF2.png" alt="enter image description here"></a></p>
  
  <p>But when I generate an apk (using command: flutter build apk) to test in my device android, The map is not showing:</p>
  
  <p><a href="https://i.stack.imgur.com/QSPLn.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QSPLn.jpg" alt="enter image description here"></a></p>
  
  <p>My main.dart:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>import 'package:flutter/material.dart';
  import 'package:flutter_map/flutter_map.dart';
  import 'package:latlong/latlong.dart';
   
  void main() =&gt; runApp(new MyApp());
   
  class MyApp extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return new MaterialApp(
        home: new MyHomePage(),
      );
    }
  }
   
  class MyHomePage extends StatefulWidget {
    @override
    _MyHomePageState createState() =&gt; new _MyHomePageState();
  }
   
  class _MyHomePageState extends State&lt;MyHomePage&gt; {
    @override
    Widget build(BuildContext context) {
      return new Scaffold(
          appBar: new AppBar(title: new Text('Leaflet Maps')),
          body: new FlutterMap(
              options: new MapOptions(
                  center: new LatLng(40.71, -74.00), minZoom: 10.0),
              layers: [
                new TileLayerOptions(
                    urlTemplate:"https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png",
                    subdomains: ['a', 'b', 'c']),
                new MarkerLayerOptions(markers: [
                  new Marker(
                      width: 45.0,
                      height: 45.0,
                      point: new LatLng(40.73, -74.00),
                      builder: (context) =&gt; new Container(
                            child: IconButton(
                              icon: Icon(Icons.location_on),
                              color: Colors.red,
                              iconSize: 45.0,
                              onPressed: () {
                                print('Marker tapped');
                              },
                            ),
                          ))
                ])
              ]));
    }
  }</code></pre>
  </div>
  </div>
  </p>
  
  <p>My pubspec.yaml:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>name: mapas
  description: A new Flutter project.
  
  # The following defines the version and build number for your application.
  # A version number is three numbers separated by dots, like 1.2.43
  # followed by an optional build number separated by a +.
  # Both the version and the builder number may be overridden in flutter
  # build by specifying --build-name and --build-number, respectively.
  # In Android, build-name is used as versionName while build-number used as versionCode.
  # Read more about Android versioning at https://developer.android.com/studio/publish/versioning
  # In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
  # Read more about iOS versioning at
  # https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
  version: 1.0.0+1
  
  environment:
    sdk: "&gt;=2.1.0 &lt;3.0.0"
  
  dependencies:
    flutter:
      sdk: flutter
    flutter_map: 0.8.2
  
    # The following adds the Cupertino Icons font to your application.
    # Use with the CupertinoIcons class for iOS style icons.
    cupertino_icons: ^0.1.2
  
  dev_dependencies:
    flutter_test:
      sdk: flutter
  
  
  # For information on the generic Dart part of this file, see the
  # following page: https://dart.dev/tools/pub/pubspec
  
  # The following section is specific to Flutter.
  flutter:
  
    # The following line ensures that the Material Icons font is
    # included with your application, so that you can use the icons in
    # the material Icons class.
    uses-material-design: true
  
    # To add assets to your application, add an assets section, like this:
    # assets:
    #  - images/a_dot_burr.jpeg
    #  - images/a_dot_ham.jpeg
  
    # An image asset can refer to one or more resolution-specific "variants", see
    # https://flutter.dev/assets-and-images/#resolution-aware.
  
    # For details regarding adding assets from package dependencies, see
    # https://flutter.dev/assets-and-images/#from-packages
  
    # To add custom fonts to your application, add a fonts section here,
    # in this "flutter" section. Each entry in this list should have a
    # "family" key with the font family name, and a "fonts" key with a
    # list giving the asset and other descriptors for the font. For
    # example:
    # fonts:
    #   - family: Schyler
    #     fonts:
    #       - asset: fonts/Schyler-Regular.ttf
    #       - asset: fonts/Schyler-Italic.ttf
    #         style: italic
    #   - family: Trajan Pro
    #     fonts:
    #       - asset: fonts/TrajanPro.ttf
    #       - asset: fonts/TrajanPro_Bold.ttf
    #         weight: 700
    #
    # For details regarding fonts from package dependencies,
    # see https://flutter.dev/custom-fonts/#from-packages</code></pre>
  </div>
  </div>
  </p>
  
  <p>Pd1: I'm not using Google Maps, I Use OpenStreetMap.</p>
  
  <p>Pd2: I test the apk in several devices Android, always the map is blank.</p>
  
  <p>Any suggestions ??</p>