Add logout button (Fixes #1)

lib/api/cache.dart

@@ -14,6 +14,13 @@ class APICache {
     feeds = ObjectCache(api);
     groups = ObjectCache(api);
   }
+
+  void clear() {
+    items._items.clear();
+    feeds._items.clear();
+    groups._items.clear();
+    feedsGroups.clear();
+  }
 }
 
 class ObjectCache<K, T> {
@@ -40,7 +47,8 @@ class ObjectCache<K, T> {
 class ItemCache extends ObjectCache<int, Item> {
   /// Get all items for a given feed
   List<Item> getForFeed(int feed) {
-    if (api.cache.feeds.get(feed) == null) throw Exception('Feed $feed doesn\'t exist');
+    if (api.cache.feeds.get(feed) == null)
+      throw Exception('Feed $feed doesn\'t exist');
     return _items.values.where((item) => item.feedId == feed).toList();
   }
 

lib/main.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 
+import 'package:feet/pages/login.dart';
 import 'package:feet/widgets/centered_page_hint.dart';
 import 'package:feet/widgets/homepage_post.dart';
 import 'package:feet/widgets/login_prompt.dart';
@@ -167,9 +168,49 @@ class _MyHomePageState extends State<MyHomePage> {
               });
             },
             icon: const Icon(Icons.replay_outlined),
+          ), // Refresh
+          PopupMenuButton(
+              itemBuilder: (context) => [
+                    PopupMenuItem(
+                      value: "log_out",
+                      child: const Text("Log out"),
+                      onTap: () {
+                        Future.delayed(
+                          const Duration(seconds: 0),
+                          () => showDialog(
+                            context: context,
+                            builder: (context) => AlertDialog(
+                              title: const Text("Log out"),
+                              content: const Text(
+                                  "Are you sure you want to log out?"),
+                              actions: [
+                                TextButton(
+                                    onPressed: () async {
+                                      Navigator.pop(context);
+                                      await widget.prefs.clear();
+
+                                      setState(() {
+                                        widget.api.apiKey = null;
+                                        widget.api.apiUrl = null;
+                                        widget.api.cache.clear();
+                                      });
+                                    },
+                                    child: const Text("Do it!")),
+                                TextButton(
+                                  onPressed: () {
+                                    Navigator.pop(context);
+                                  },
+                                  child: const Text("Nevermind"),
                                 ),
                               ],
                             ),
+                          ),
+                        );
+                      },
+                    )
+                  ]),
+        ],
+      ),
       bottomNavigationBar: BottomNavigationBar(
         currentIndex: _index,
         onTap: (value) => setState(() => _index = value),