Feat: Zeigt Knöpfe zum Transaktion erstellen nur an, wenn ein Konto ausgewählt ist

lib/Pages/Misc/floating_creation_button.dart

@@ -24,33 +24,57 @@ class _FloatingCreationButtonState extends State<FloatingCreationButton> {
   final _key = GlobalKey<ExpandableFabState>();
 
   @override
-  Widget build(final BuildContext context) => ExpandableFab(
-    key: _key,
-    openButtonBuilder: RotateFloatingActionButtonBuilder(
-      child: const Icon(Icons.add),
-    ),
-    type: ExpandableFabType.up,
-    childrenAnimation: ExpandableFabAnimation.none,
-    distance: 70,
-    children: <Widget>[
+  void initState() {
+    super.initState();
+
+    _accountController.selected.addListener(() {
+      if (mounted) {
+        setState(() {});
+      }
+    });
+  }
+
+  @override
+  Widget build(final BuildContext context) {
+    final List<Widget> fabs = [];
+    if (_accountController.selected.value != null) {
+      fabs
+        ..add(
+          _expandableButton(
+            label: 'Neue Transaktion',
+            icon: Icons.swap_horiz,
+            onPressed: _transactionController.newTransactionHandler,
+          ),
+        )
+        ..add(
+          _expandableButton(
+            label: 'Neue wiederkehrende Transaktion',
+            icon: Icons.repeat,
+            onPressed:
+                _recurringTransactionController.newRecurringTransactionHandler,
+          ),
+        );
+    }
+
+    fabs.add(
       _expandableButton(
         label: 'Neues Konto',
         icon: Icons.account_balance_wallet,
         onPressed: _accountController.newAccountHandler,
       ),
-      _expandableButton(
-        label: 'Neue Transaktion',
-        icon: Icons.swap_horiz,
-        onPressed: _transactionController.newTransactionHandler,
+    );
+
+    return ExpandableFab(
+      key: _key,
+      openButtonBuilder: RotateFloatingActionButtonBuilder(
+        child: const Icon(Icons.add),
       ),
-      _expandableButton(
-        label: 'Neue wiederkehrende Transaktion',
-        icon: Icons.repeat,
-        onPressed:
-            _recurringTransactionController.newRecurringTransactionHandler,
-      ),
-    ],
-  );
+      type: ExpandableFabType.up,
+      childrenAnimation: ExpandableFabAnimation.none,
+      distance: 70,
+      children: fabs,
+    );
+  }
 
   Widget _expandableButton({
     required final String label,