diff --git a/lib/src/webview.dart b/lib/src/webview.dart
index 28d405e..01e6a94 100644
--- a/lib/src/webview.dart
+++ b/lib/src/webview.dart
@@ -565,7 +565,7 @@ class _WebviewState extends State<Webview> {
     _controller._permissionRequested = widget.permissionRequested;
 
     // Report initial surface size
-    WidgetsBinding.instance.addPostFrameCallback((_) => _reportSurfaceSize());
+    WidgetsBinding?.instance.addPostFrameCallback((_) => _reportSurfaceSize());
 
     _cursorSubscription = _controller._cursor.listen((cursor) {
       setState(() {