Fix application can't exit bug

src/main.cpp

@@ -52,14 +52,16 @@ int main(int argc, char* argv[])
     SQLHelper::Open();
     MainWindow w;
     w.showFullScreen();
+    {
+
         LoginWindow l;
         needLogin:
         l.showFullScreen();
         int rec = l.exec();
-    if (rec !=QDialog::Accepted )
+        if (rec != QDialog::Accepted) {
-    {
             return 0;
         }
+    }
 //    l.deleteLater();
     w.centerWidgetShow();