Get Json response when Webview redirect to another page in Flutter

Question

flutter_webview_plugin^0.3.11 I am building a payment gateway and in 3d secure mode I need to use Webview. Launch Webview with a response in type of html string.

   return Scaffold(
  body: WebviewScaffold(
    withJavascript: true,
    key: _scaffoldKey,
    url: new Uri.dataFromString(widget.d3sc, mimeType: 'text/html').toString(),
  ),
);

It prints on the screen the security code phase. When I submit the code it redirects automatically to callback url and I can not manage to connect or get response from this url. I need to get response when code is submitted and page is redirected for having token for closing 3d secure payment. Any idea or solution ?

Tried below code. Although it prints the redirected url, there is no json response in response element.

 webView.launch(new Uri.dataFromString(widget.d3sc, mimeType: 'text/html').toString() ,withJavascript: true, withLocalStorage: true);
  webView.show();

  webView.onUrlChanged.listen((String event) async {
    print("${event} even eevent");
    setState(() {
      webView
          .evalJavascript("document.documentElement.innerText")
          .then((response) => print("$response response response "));

    });
  });

Solution

I was not aware that I found the solution because the html content was very complex. By using webview_flutter plugin problem is sorted. Build your widget as it is;

WebView(
    initialUrl: new Uri.dataFromString(widget.d3sc, mimeType: 'text/html').toString(),

    onWebViewCreated: (controller) {
      _controller = controller;
    },
    javascriptMode: JavascriptMode.unrestricted,
    gestureNavigationEnabled: true,
    onPageFinished: (_) {
      readResponse();
    },
  )

readResponse function is called whenever navigation occurs and page opening finished. We can get page's html content as string by using following function;

    void readResponse() async
  {
  

    setState(() {
      _controller.evaluateJavascript("document.documentElement.innerHTML").then((value) async {

        if(value.contains("name=\"paymentId\"")){

// value contains the html data of page as string
 ...

I could not convert html data to json map but we can reach whatever we want in this string by simply using substring method.

Note: webview_flutter version ^1.0.7 is used for solution in this case.