修改

lib/login/login_page.dart

@@ -398,7 +398,7 @@ class _MyLoginPageState extends State<LoginPage> with TickerProviderStateMixin {
       firstCurve: Curves.easeInQuart,
       secondCurve: Curves.easeInQuart,
       crossFadeState: isShowLogin ? CrossFadeState.showSecond : CrossFadeState.showFirst,
-      duration: Duration(milliseconds: Platform.isIOS ? 1000 : 300),
+      duration: Duration(milliseconds: Platform.isIOS ? 1000 : 1000),
     );
   }