A feature-rich cross-platform webview using webview_flutter for mobile and iframe for web

A feature-rich cross-platform webview using webview_flutter for mobile and iframe for web. JS interop-ready.

Gallery

Mobile
Web

Basic usage

1. Create a WebViewXController inside your stateful widget

late WebViewXController webviewController;

2. Add the WebViewX widget inside the build method, and set the onWebViewCreated callback in order to retrieve the controller when the webview is initialized

WebViewX(
    initialContent: '<h2> Hello, world! </h2>',
    initialSourceType: SourceType.HTML,
    onWebViewCreated: (controller) => webviewController = controller,
    ...
    ... other options
);

Important !

If you need to add other widgets on top of the webview (e.g. inside a Stack widget), you MUST wrap those widgets with a WebViewAware widget.
This does nothing on mobile, but on web it allows widgets on top to intercept gestures. Otherwise, those widgets may not be clickable and/or the iframe will behave weird (unexpected refresh/reload – this is a well known issue).

Also, if you add widgets on top of the webview, wrap them and then you notice that the iframe still reloads unexpectedly, you should check if there are other widgets that sit on top without being noticed, or try to wrap InkWell, GestureRecognizer or Button widgets to see which one causes the problem.

3. Interact with the controller (run the example app to check out some use cases)

webviewController.loadContent(
    'https://flutter.dev',
    SourceType.url,
);
webviewController.goBack();

webviewController.goForward();
...
...

Features

Note: For more detailed information about things such as EmbeddedJsContent, please visit each own’s .dart file from the utils folder.

• Widget properties

• Controller properties

Limitations and notes

While this package aims to put together the best of both worlds, there are differences between web and mobile.

• Running and building

  First, this package was being developed while the default web renderer was html. Now(Flutter 2, Dart 2.12), the default renderer is canvaskit.

  From my experience, this package does behave a little bit weird on canvaskit, so you should use the html renderer.

  To do this, you have to run your ordinary flutter run -d chrome command with the --web-renderer html extra argument, like this:

  flutter run -d chrome --web-renderer html

  for running and

  flutter build web --web-renderer html

  for building.

• Diferences between Web and Mobile behaviour:

  See issues/#27

• About content loading on Web

  To make the web version (iframe) work as it is, I had to use some of the code from x-frame bypass in order to make a request to a CORS proxy, which removes the headers that block iframe embeddings.

  This might seem like a hack, and it really is, but I couldn’t find any other way to make the iframe behave similar to the mobile webview (which is some kind of an actual browser, that’s why everything works there by default).

• About Web navigation

  On web, the history navigation stack is built from scratch because I couldn’t handle iframe’s internal history the right way.

Known issues and TODOs

• [ x ] On web, user-agent and headers only work when using SourceType.urlBypass, and they only have effect the first time being used (view/web.dart)
• [ x ] On web, it should be possible to send any errors caught when loading an urlBypass to a dart callback, which will then be sent through the onWebResourceError callback, just like on the mobile version (utils/x_frame_options_bypass.dart)
• [ x ] On web, it should be possible to add a custom proxy list without the js null-checking mess (utils/x_frame_options_bypass.dart)
• [ ? ] Eventually (if possible), most if not all properties from WebSpecificParams and MobileSpecificParams should merge and theese two objects may disappear
• [ x ] On mobile, the controller’s value’s source type becomes out of sync when moving back and forth in history. This happens because the url change is not yet intercepted and set the model accordingly (shouldn’t be hard to fix).
• On mobile, the controller’s callJsMethod doesnt throw an error if the operation failed. Instead it only shows the error in console.
• Add tests
• List open, there may be others

Credits

This package wouldn’t be possible without the following:

• webview_flutter for the mobile version
• easy_web_view for ideas and starting point for the web version
• pointer_interceptor for fixing iframe issues when other widgets are on top of it (see above)
• x-frame-bypass for allowing the iframe to bypass websites’ X-Frame-Options: deny/same-origin headers, thus allowing us to load any webpage (just like on mobile)
• https://cors.bridged.cc/ for the free CORS proxy
• https://api.codetabs.com/ for the free CORS proxy

• And last but not least, http://deversoft.ro (the company I work for) for motivating me throughout the development process

License

MIT