Add locations and save them, remove locations and delete them

lib/main.dart

@@ -17,41 +17,52 @@ class MyApp extends StatefulWidget {
 }
 
 class _MyAppState extends State<MyApp> {
+  List<String> _locations = [];
+
   @override
-  Widget build(BuildContext context) {
-    return MaterialApp(
-      title: 'Wetter',
-      theme: ThemeData(
-        primarySwatch: Colors.blue,
-        textTheme: const TextTheme(
-          headline1: TextStyle(fontSize: 72.0, fontWeight: FontWeight.bold),
-          headline6: TextStyle(fontSize: 36.0, fontStyle: FontStyle.italic),
-          bodyText2: TextStyle(fontSize: 14.0, fontFamily: 'Hind'),
-        ),
-      ),
-      home: DefaultTabController(
-        length: 3,
-        child: Scaffold(
-          appBar: AppBar(
-            title: const Text('Wetter'),
-            bottom: const TabBar(
-              tabs: [
-                Tab(icon: Text("Hamburg")),
-                Tab(icon: Text("Frankfurt")),
-                Tab(icon: Text("Freiburg")),
-              ],
-            ),
-          ),
-          drawer: const NavBar(),
-          body: const TabBarView(
-            children: [
-              MainWeatherView(53.46, 9.98),
-              MainWeatherView(50.15, 8.70),
-              MainWeatherView(47.99, 7.85)
-            ],
-          ),
+  void initState() {
+    _locations = UserPreferences.getSavedLocations();
+    super.initState();
+  }
+
+  Widget buildContent() {
+    return DefaultTabController(
+      length: _locations.length,
+      child: Scaffold(
+        appBar: AppBar(
+          title: const Text('Wetter'),
+          bottom: (_locations.isEmpty)
+              ? null
+              : TabBar(
+                  tabs: [for (String name in _locations) Tab(icon: Text(name))],
+                ),
         ),
+        drawer: const NavBar(),
+        body: (_locations.isEmpty)
+            ? const Text("No locations")
+            : TabBarView(
+                children: [
+                  for (String name in _locations)
+                    MainWeatherView(UserPreferences.getLat(name),
+                        UserPreferences.getLon(name))
+                ],
+              ),
       ),
     );
   }
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+        title: 'Wetter',
+        theme: ThemeData(
+          primarySwatch: Colors.blue,
+          textTheme: const TextTheme(
+            headline1: TextStyle(fontSize: 72.0, fontWeight: FontWeight.bold),
+            headline6: TextStyle(fontSize: 36.0, fontStyle: FontStyle.italic),
+            bodyText2: TextStyle(fontSize: 14.0, fontFamily: 'Hind'),
+          ),
+        ),
+        home: buildContent());
+  }
 }