main, swap the switch with text rather than disabling, allows giving a better error message.

lib/main.dart

@@ -79,8 +79,8 @@ class HomeScreen extends StatefulWidget {
 class _HomeScreenState extends State<HomeScreen> {
   final _latController = TextEditingController();
   final _lngController = TextEditingController();
-  final _sunsetController = TextEditingController();
+  final _sunsetController = TextEditingController(text: "18:00");
-  final _minutesController = TextEditingController(text: '30');
+  final _minutesController = TextEditingController(text: "30");
 
   final FlutterLocalNotificationsPlugin _notifications =
       FlutterLocalNotificationsPlugin();
@@ -559,18 +559,23 @@ class _HomeScreenState extends State<HomeScreen> {
 
                   // --- Toggle ---
                   Expanded(
-                    child: SwitchListTile(
+                    child:
-                      //title: const Text('Enable Sunset Alarm'),
+                        _validTime
-                      title: Text(_alarmEnabled ? 'Sunset Alarm Enabled' : ""),
+                            ? SwitchListTile(
+                              title: Text(
+                                _alarmEnabled ? 'Sunset Alarm Enabled' : "",
+                              ),
                       subtitle: Text(
-                        _alarmEnabled
+                                _validTime
+                                    ? _alarmEnabled
                             ? '${_minutesBefore} Minute${_plural} Before @ $_alarmDisplayTime'
-                            : "",
+                                        : ""
-                      ),
+                                    : "Add Time",
-                      value: _validTime ? _alarmEnabled : false,
-                      // If _isDataLoaded is false, onChanged is null, disabling the switch
-                      onChanged: _validTime ? _toggleAlarm : null,
                       ),
+                              value: _alarmEnabled,
+                              onChanged: _toggleAlarm,
+                            )
+                            : Center(child: Text("Sunset Time Invalid")),
                   ),
                 ],
               ),