Adding OpenHaystack Mobile app

Co-Authored-By: Lukas Burg <lukas.burg@hemalu.de>

openhaystack-mobile/lib/preferences/preferences_page.dart

@@ -0,0 +1,58 @@
+import 'package:flutter/material.dart';
+import 'package:provider/provider.dart';
+import 'package:openhaystack_mobile/location/location_model.dart';
+import 'package:openhaystack_mobile/preferences/user_preferences_model.dart';
+
+class PreferencesPage extends StatefulWidget {
+
+  /// Displays this preferences page with information about the app.
+  const PreferencesPage({ Key? key }) : super(key: key);
+
+  @override
+  _PreferencesPageState createState() => _PreferencesPageState();
+}
+
+class _PreferencesPageState extends State<PreferencesPage> {
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text('Settings'),
+      ),
+      body: Consumer<UserPreferences>(
+        builder: (BuildContext context, UserPreferences prefs, Widget? child) {
+          return Center(
+            child: Container(
+              constraints: const BoxConstraints(maxWidth: 500),
+              child: ListView(
+                children: [
+                  SwitchListTile(
+                    title: const Text('Show this devices location'),
+                    value: !prefs.locationPreferenceKnown! || (prefs.locationAccessWanted ?? true),
+                    onChanged: (showLocation) {
+                      prefs.setLocationPreference(showLocation);
+                      var locationModel = Provider.of<LocationModel>(context, listen: false);
+                      if (showLocation) {
+                        locationModel.requestLocationUpdates();
+                      } else {
+                        locationModel.cancelLocationUpdates();
+                      }
+                    },
+                  ),
+                  ListTile(
+                    title: TextButton(
+                      child: const Text('About'),
+                      onPressed: () => showAboutDialog(
+                        context: context,
+                      ),
+                    ),
+                  ),
+                ],
+              ),
+            ),
+          );
+        },
+      ),
+    );
+  }
+}

openhaystack-mobile/lib/preferences/user_preferences_model.dart

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+import 'package:flutter/foundation.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+const introductionShownKey = 'INTRODUCTION_SHOWN';
+const locationPreferenceKnownKey = 'LOCATION_PREFERENCE_KNOWN';
+const locationAccessWantedKey = 'LOCATION_PREFERENCE_WANTED';
+
+class UserPreferences extends ChangeNotifier {
+
+  /// If these settings are initialized.
+  bool initialized = false;
+  /// The shared preferences storage.
+  SharedPreferences? _prefs;
+
+  /// Manages information about the users preferences.
+  UserPreferences() {
+    _initializeAsync();
+  }
+
+  /// Initialize shared preferences access
+  void _initializeAsync() async {
+    _prefs = await SharedPreferences.getInstance();
+
+    // For Debugging:
+    // await prefs.clear();
+
+    initialized = true;
+    notifyListeners();
+  }
+
+  /// Returns if the introduction should be shown.
+  bool? shouldShowIntroduction() {
+    if (_prefs == null) {
+      return null;
+    } else {
+      if (!_prefs!.containsKey(introductionShownKey)) {
+        return true; // Initial start of the app
+      }
+      return _prefs?.getBool(introductionShownKey);
+    }
+  }
+
+  /// Returns if the user's locaiton preference is known.
+  bool? get locationPreferenceKnown {
+    return _prefs?.getBool(locationPreferenceKnownKey) ?? false;
+  }
+
+  /// Returns if the user desires location access.
+  bool? get locationAccessWanted {
+    return _prefs?.getBool(locationAccessWantedKey);
+  }
+
+  /// Updates the location access preference of the user.
+  Future<bool> setLocationPreference(bool locationAccessWanted) async {
+    _prefs ??= await SharedPreferences.getInstance();
+    var success = await _prefs!.setBool(locationPreferenceKnownKey, true);
+    if (!success) {
+      return Future.value(false);
+    } else {
+      var result = await _prefs!.setBool(locationAccessWantedKey, locationAccessWanted);
+      notifyListeners();
+      return result;
+    }
+    
+  }
+
+}