Added feedback on successfully export

Feladat1/UI/MainWindow/MainWindow.cs

@@ -1,5 +1,4 @@
 using Adw;
-using GLib;
 using Logic;
 using Models;
 
@@ -7,6 +6,9 @@ namespace Feladat1.UI.MainWindow;
 
 public class MainWindow
 {
+    private ToastOverlay toastOverlay;
+    private const string toastOverlayId = "toast_overlay";
+
     private IUserService userService;
     private const string windowId = "main_window";
 
@@ -88,6 +90,12 @@ public class MainWindow
             {
                 throw new NullReferenceException(passwordLabelId);
             }
+
+            toastOverlay = builder.GetObject(toastOverlayId) as ToastOverlay;
+            if (toastOverlay == null)
+            {
+                throw new NullReferenceException(toastOverlayId);
+            }
         }
         catch (NullReferenceException e)
         {
@@ -112,13 +120,9 @@ public class MainWindow
             int returnCode = userService.Create(userNameField.GetText(), emailField.GetText(), passwordField.GetText());
             if (returnCode == 0)
             {
-                ToastOverlay overlay = new ToastOverlay();
-                overlay.SetParent(Window);
-
                 Toast toast = new Toast();
-                toast.SetButtonLabel("New user exported successfully");
-
-                overlay.AddToast(toast);
+                toast.SetTitle("User data exported successfully");
+                toastOverlay.AddToast(toast);
 
                 User user = userService.Read();
                 emailLabel.Text_ = user.Email;