Fixed _CastError when running example App (#4390)

Author: mvanbeusekom

packages/webview_flutter/webview_flutter/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.1.1
+
+* Fixed `_CastError` that was thrown when running the example App.
+
 ## 2.1.0
 
 * Migrated to fully federated architecture.

packages/webview_flutter/webview_flutter/example/lib/main.dart

@@ -302,15 +302,15 @@ class NavigationControls extends StatelessWidget {
           (BuildContext context, AsyncSnapshot<WebViewController> snapshot) {
         final bool webViewReady =
             snapshot.connectionState == ConnectionState.done;
-        final WebViewController controller = snapshot.data!;
+        final WebViewController? controller = snapshot.data;
         return Row(
           children: <Widget>[
             IconButton(
               icon: const Icon(Icons.arrow_back_ios),
               onPressed: !webViewReady
                   ? null
                   : () async {
-                      if (await controller.canGoBack()) {
+                      if (await controller!.canGoBack()) {
                         await controller.goBack();
                       } else {
                         // ignore: deprecated_member_use
@@ -326,7 +326,7 @@ class NavigationControls extends StatelessWidget {
               onPressed: !webViewReady
                   ? null
                   : () async {
-                      if (await controller.canGoForward()) {
+                      if (await controller!.canGoForward()) {
                         await controller.goForward();
                       } else {
                         // ignore: deprecated_member_use
@@ -343,7 +343,7 @@ class NavigationControls extends StatelessWidget {
               onPressed: !webViewReady
                   ? null
                   : () {
-                      controller.reload();
+                      controller!.reload();
                     },
             ),
           ],

packages/webview_flutter/webview_flutter/pubspec.yaml

@@ -2,7 +2,7 @@ name: webview_flutter
 description: A Flutter plugin that provides a WebView widget on Android and iOS.
 repository: https://github.com/flutter/plugins/tree/master/packages/webview_flutter/webview_flutter
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+webview%22
-version: 2.1.0
+version: 2.1.1
 
 environment:
   sdk: ">=2.14.0 <3.0.0"