Flutter Webview two way communication with Javascript

Here is an example of communication from Javascript code to flutter.

In Flutter build your WebView like :

WebView(
              initialUrl: url,
              javascriptMode: JavascriptMode.unrestricted,
              javascriptChannels: Set.from([
                JavascriptChannel(
                    name: 'Print',
                    onMessageReceived: (JavascriptMessage message) {
                      //This is where you receive message from 
                      //javascript code and handle in Flutter/Dart
                      //like here, the message is just being printed
                      //in Run/LogCat window of android studio
                      print(message.message);
                    })
              ]),
              onWebViewCreated: (WebViewController w) {
                webViewController = w;
              },
            )

and in Your HTMLfile:

<script type="text/javascript">
    Print.postMessage('Hello World being called from Javascript code');
</script>

When you run this code, you shall be able to see log “Hello World being called from Javascript code” in the LogCat/Run window of android studio.