Redesigned

lib/components/favoriteButton.dart

@@ -0,0 +1,67 @@
+import 'package:flutter/material.dart';
+import '../settings.dart';
+import 'menuiButton.dart';
+
+class FavoriteButton extends StatefulWidget {
+  final String id;
+
+  FavoriteButton({@required this.id, Key key}) : super(key: key);
+
+  @override
+  _FavoriteButtonState createState() => _FavoriteButtonState();
+}
+
+class _FavoriteButtonState extends State<FavoriteButton> {
+  final MenuiSettings settings = new MenuiSettings();
+  Future<bool> isInFavorites;
+  bool inFavorites = false;
+
+  @override
+  void initState() {
+    super.initState();
+    isInFavorites = settings.isInFavorites(widget.id);
+  }
+
+  @override
+  Widget build(BuildContext context) => FutureBuilder(
+        initialData: false,
+        future: isInFavorites,
+        builder: (context, snapshot) {
+          if (snapshot.hasData) {
+            inFavorites = snapshot.data;
+            if (inFavorites) {
+              return MenuiButton(
+                color: Colors.orange,
+                icon: Icons.favorite_rounded,
+                text: "Usuń",
+                onPressed: () {
+                  settings.addToFavorites(widget.id);
+                  setState(() {
+                    isInFavorites = settings.isInFavorites(widget.id);
+                  });
+                },
+              );
+            } else {
+              return MenuiButton(
+                color: Colors.grey,
+                icon: Icons.favorite_rounded,
+                text: "Dodaj",
+                onPressed: () {
+                  settings.addToFavorites(widget.id);
+                  setState(() {
+                    isInFavorites = settings.isInFavorites(widget.id);
+                  });
+                },
+              );
+            }
+          } else {
+            return MenuiButton(
+              color: Colors.grey,
+              icon: Icons.favorite_rounded,
+              text: "Dodaj",
+              onPressed: () {},
+            );
+          }
+        },
+      );
+}