Load user preferences at start of app. Manage locations: user is able to add locations by lat and lon to shared preferences

lib/components/locations/add_location_form.dart

@@ -1,10 +1,11 @@
 import 'package:flutter/material.dart';
-import 'package:shared_preferences/shared_preferences.dart';
 
 class AddLocationsForm extends StatefulWidget {
-  final SharedPreferences prefs;
+  final Function saveNewLocation;
-
+  final List<String> savedLocations;
-  const AddLocationsForm(this.prefs, {Key? key}) : super(key: key);
+  const AddLocationsForm(
+      {Key? key, required this.saveNewLocation, required this.savedLocations})
+      : super(key: key);
 
   @override
   AddLocationsFormState createState() => AddLocationsFormState();
@@ -16,12 +17,10 @@ class AddLocationsFormState extends State<AddLocationsForm> {
   String? newLocationName;
   double? newLatitude;
   double? newLongitude;
-  late List<String> savedLocations;
 
   @override
   void initState() {
     super.initState();
-    savedLocations = widget.prefs.getStringList('savedLocations') ?? [];
   }
 
   @override
@@ -33,7 +32,7 @@ class AddLocationsFormState extends State<AddLocationsForm> {
   void _submitLocation() {
     if (_formKey.currentState!.validate()) {
       _formKey.currentState!.save();
-      _saveLocationToPrefs(newLocationName!, newLatitude!, newLongitude!);
+      widget.saveNewLocation(newLocationName!, newLatitude!, newLongitude!);
       _formKey.currentState!.reset();
       newLocationName = null;
       newLatitude = null;
@@ -41,13 +40,6 @@ class AddLocationsFormState extends State<AddLocationsForm> {
     }
   }
 
-  void _saveLocationToPrefs(String name, double lat, double lon) {
-    savedLocations.add(name);
-    widget.prefs.setStringList('savedLocations', savedLocations);
-    widget.prefs.setDouble("$name-lat", lat);
-    widget.prefs.setDouble("$name-lon", lon);
-  }
-
   @override
   Widget build(BuildContext context) {
     return Form(
@@ -65,7 +57,7 @@ class AddLocationsFormState extends State<AddLocationsForm> {
                   if (value == null || value.isEmpty) {
                     return "Please enter a name for the new location";
                   }
-                  if (savedLocations.contains(value)) {
+                  if (widget.savedLocations.contains(value)) {
                     return "Location name already in use";
                   }
                   return null;

lib/components/locations/manage_single_location.dart

@@ -0,0 +1,21 @@
+import 'package:flutter/material.dart';
+
+class ManageSingleLocation extends StatelessWidget {
+  final String name;
+  final Function delete;
+  const ManageSingleLocation(
+      {Key? key, required this.name, required this.delete})
+      : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return Card(
+        child: Padding(
+            padding: const EdgeInsets.all(10),
+            child: Row(children: [
+              Text(name, style: Theme.of(context).textTheme.headline5),
+              const Spacer(),
+              const Icon(Icons.delete_sharp)
+            ])));
+  }
+}

lib/components/settings_form.dart

@@ -1,5 +1,5 @@
 import 'package:flutter/material.dart';
-import 'package:shared_preferences/shared_preferences.dart';
+import 'package:wetter/services/user_preferences.dart';
 
 class SettingsForm extends StatefulWidget {
   const SettingsForm({Key? key}) : super(key: key);
@@ -9,20 +9,13 @@ class SettingsForm extends StatefulWidget {
 }
 
 class SettingsFormState extends State<SettingsForm> {
-  SharedPreferences? prefs;
   int _daysToLoad = 7;
   final _formKey = GlobalKey<FormState>();
 
   @override
   void initState() {
+    _daysToLoad = UserPreferences.preferences!.getInt("daysToLoad") ?? 7;
     super.initState();
-    initializePreferences().whenComplete(() => setState(() {
-          _daysToLoad = prefs?.getInt("daysToLoad") ?? 7;
-        }));
-  }
-
-  Future<void> initializePreferences() async {
-    prefs = await SharedPreferences.getInstance();
   }
 
   @override
@@ -35,12 +28,13 @@ class SettingsFormState extends State<SettingsForm> {
               value: _daysToLoad.toDouble(),
               min: 1.0,
               max: 14.0,
-              divisions: 14,
+              divisions: 13,
               label: _daysToLoad.round().toString(),
               onChanged: (double value) {
                 setState(() {
                   _daysToLoad = value.round();
-                  prefs?.setInt("daysToLoad", _daysToLoad);
+                  UserPreferences.preferences!
+                      .setInt("daysToLoad", _daysToLoad);
                 });
               },
             )

lib/main.dart

@@ -1,8 +1,13 @@
 import 'package:flutter/material.dart';
 import 'package:wetter/components/main_menu.dart';
 import 'package:wetter/screens/main_weather_view.dart';
+import 'package:wetter/services/user_preferences.dart';
 
-void main() => runApp(const MyApp());
+void main() async {
+  WidgetsFlutterBinding.ensureInitialized();
+  await UserPreferences.init();
+  runApp(const MyApp());
+}
 
 class MyApp extends StatefulWidget {
   const MyApp({super.key});

lib/screens/locations.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
-import 'package:shared_preferences/shared_preferences.dart';
 import 'package:wetter/components/locations/add_location_form.dart';
+import 'package:wetter/components/locations/manage_single_location.dart';
+import 'package:wetter/services/user_preferences.dart';
 
 class Locations extends StatefulWidget {
   const Locations({super.key});
@@ -10,18 +11,21 @@ class Locations extends StatefulWidget {
 }
 
 class _LocationsState extends State<Locations> {
-  late final SharedPreferences? prefs;
+  List<String> locations = [];
-
   @override
   void initState() {
-    SharedPreferences.getInstance().then((value) => prefs = value);
+    locations = UserPreferences.getSavedLocations();
     super.initState();
   }
 
-  Future<void> initializePreferences() async {
+  void saveNewLocation(String name, double lat, double lon) {
-    prefs = await SharedPreferences.getInstance();
+    setState(() {
+      locations = UserPreferences.saveNewLocation(name, lat, lon);
+    });
   }
 
+  void deleteLocation(String name) {}
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(
@@ -29,8 +33,20 @@ class _LocationsState extends State<Locations> {
           title: const Text('Locations'),
         ),
         body: Padding(
-          padding: const EdgeInsets.all(20),
+            padding: const EdgeInsets.all(20),
-          child: AddLocationsForm(prefs!),
+            child: Center(
-        ));
+                child: Column(
+                    mainAxisAlignment: MainAxisAlignment.spaceEvenly,
+                    children: [
+                  for (String name in locations)
+                    ManageSingleLocation(name: name, delete: deleteLocation),
+                  ...[
+                    Expanded(
+                      child: AddLocationsForm(
+                          saveNewLocation: saveNewLocation,
+                          savedLocations: locations),
+                    )
+                  ],
+                ]))));
   }
 }

lib/services/user_preferences.dart

@@ -0,0 +1,22 @@
+import 'package:shared_preferences/shared_preferences.dart';
+
+class UserPreferences {
+  static List<String> _savedLocations = [];
+  static SharedPreferences? preferences;
+  static Future<void> init() async {
+    preferences = await SharedPreferences.getInstance();
+    _savedLocations = preferences!.getStringList('savedLocations') ?? [];
+  }
+
+  static List<String> getSavedLocations() {
+    return _savedLocations;
+  }
+
+  static List<String> saveNewLocation(String name, double lat, double lon) {
+    _savedLocations.add(name);
+    preferences!.setStringList('savedLocations', _savedLocations);
+    preferences!.setDouble("$name-lat", lat);
+    preferences!.setDouble("$name-lon", lon);
+    return getSavedLocations();
+  }
+}