error: LateInitializationError: Field 'connector' has not been initialized.

[nank1ro]

Hello,

I followed your example for running JS code from dart:
I've added this code:

 return WebViewX(
      width: 320,
      height: 500,
      initialContent:
          'someUrl',
      onWebViewCreated: (controller) => webviewController = controller,
      onPageFinished: (_) {
        webviewController
            .callJsMethod('testPlatformSpecificMethod', <dynamic>['Hi']);
      },
      jsContent: const {
        EmbeddedJsContent(
          webJs:
              "function testPlatformSpecificMethod(msg) { CaptchaMessenger('Web callback says: ' + msg) }",
          mobileJs:
              "function testPlatformSpecificMethod(msg) { CaptchaMessenger.postMessage('Mobile callback says: ' + msg) }",
        ),
      },
      dartCallBacks: {
        DartCallback(callBack: recaptchaCallback, name: 'CaptchaMessenger')
      },
    );

But when I run this code I always get this error:
error: LateInitializationError: Field 'connector' has not been initialized..

Additional info:

• I'm running the app on Web

[adrianflutur]

Hi, I found out where the problem is coming from

view/impl/web.dart:164

...
if (widget.initialSourceType == SourceType.html ||
    widget.initialSourceType == SourceType.urlBypass ||
    (widget.initialSourceType == SourceType.url &&
        widget.initialContent == 'about:blank')) {
   // This function sets the `connector` everytime the page is loaded
  _connectJsToFlutter(then: _callOnWebViewCreatedCallback);
} else {
  // Here the `connector` doesn't get set, so you end up getting
  // error: LateInitializationError: Field 'connector' has not been initialized
  //
  // We reach this part of the code when the `sourcetype` is url
  // and the url is not `about:blank`
  _callOnWebViewCreatedCallback();
}
...

As you can see inside the else block, the connector doesn't get set and because of that, it ends up not being initialized inside the controller.

Now, there's a small problem here: The connector cannot be set when using SourceType.url and the URL is not about:blank. This is noted here #27, precisely:

Calling any method that will interact with the page's source (i.e. call JS methods, callbacks, execute JS etc) from the controller only works when using SourceType.urlBypass or SourceType.html. This is because only in theese 2 situations the package can actually inject that JS code inside the page source. When using SourceType.url, iframe's content does not actually belong to us - it is loaded from a different domain so we're not allowed to do that.

I could add a partial workaround for this, such that the connector actually becomes the browser page, and not the iframe page. This would mean that you would have access to the browser's window object, not the iframe's one. But I'm not sure this would really solve anything, as you would get a NoSuchMethodError when calling any methods because they won't exist in the browser's window object.
(You can check out this behaviour on another branch here: https://github.com/adrianflutur/webviewx/tree/attempt-unify-url-html-controller-init)

A solution would be to change the sourceType to SourceType.urlBypass. This will allow the package to inject EmbeddedJsContent and DartCallbacks inside the page, at the cost of using a proxy server every time in order to fetch the page's HTML source.

[nank1ro]

thank you for your response. I have to try using SourceType.urlBypass and I'll let you know if this fits my needs

[adrianflutur]

Closing this for now, please open another issue if you encounter any more issues.

[Ahmadre]

@adrianflutur why is this important issue closed? The most important function in this whole plugin is NOT WORKING!