minor login fixes

lib/screens/onboarding/login/login_controller.dart

@@ -18,13 +18,29 @@ class LoginController extends ChangeNotifier {
   final model = LoginScreenModel();
   late SharedPreferences prefs;
   BuildContext context;
+  bool _disposed = false;
 
   LoginController(this.context);
 
-  Future<ApiResponse<LoginScreenModel>> login(String username, String password) async {
+  @override
+  void dispose() {
+    _disposed = true;
+    super.dispose();
+  }
+
+  void _safeNotifyListeners() {
+    if (!_disposed) {
+      notifyListeners();
+    }
+  }
+
+  Future<ApiResponse<LoginScreenModel>> login(
+    String username,
+    String password,
+  ) async {
     try {
       model.isLoading = true;
-      notifyListeners();
+      _safeNotifyListeners();
 
       prefs = await SharedPreferences.getInstance();
 
@@ -35,7 +51,7 @@ class LoginController extends ChangeNotifier {
       logger.i(response.toString());
 
       model.isLoading = false;
-      notifyListeners();
+      _safeNotifyListeners();
 
       if (response.containsKey('token')) {
         model.status = 'SUCCESS';
@@ -47,26 +63,32 @@ class LoginController extends ChangeNotifier {
         prefs.setString('lastName', response['lastName']);
         prefs.setString('phone', response['phone']);
         prefs.setString('userId', response['uuid']);
-        prefs.setString('initials', response['firstName'].substring(0, 1) + response['lastName'].substring(0, 1));
+        prefs.setString(
+          'initials',
+          response['firstName'].substring(0, 1) +
+              response['lastName'].substring(0, 1),
+        );
 
         return ApiResponse.success(model);
       } else {
         model.errorMessage =
             response['errorMessage'] ??
-            "Problem with the transaction. Please try again or contact support";
+            "Problem with the operation. Please try again or contact support";
         return ApiResponse.failure(model.errorMessage!);
       }
     } on DioException catch (e, s) {
       logger.e(s);
       model.isLoading = false;
-      notifyListeners();
-      return ApiResponse.failure(e.response?.data['errors'][0] ?? "Unknown error");
+      _safeNotifyListeners();
+      return ApiResponse.failure(
+        e.response?.data['errors'][0] ?? "Unknown error",
+      );
     } catch (e, s) {
       logger.e(s);
       model.isLoading = false;
-      notifyListeners();
+      _safeNotifyListeners();
       return ApiResponse.failure(
-        "Problem processing that transaction. Please try again or contact support",
+        "Problem processing that operation. Please try again or contact support",
       );
     }
   }