Flutter webview with custom javascriptInterfaceAdapter or invoke JS using webview controller

Issue

I have an old java project that performs in andorid webview with addJavascriptInterface

mWebView.addJavascriptInterface(new JavascriptAdapter(), "AndroidFunctions");

Within JavascriptAdapter class there is several @JavascriptInterface functions. as example

class JavascriptAdapter {
    @JavascriptInterface
    getMacAddress(){
        DeviceInfo deviceInfo = new DeviceInfo(activity);
        return deviceInfo.getMacAddress();
  }
}

now after opening the webview within android applications, using JS we can access that function like this way –

var strMacAddress = AndroidFunctions.getMACAddress();

Now I would like to achieve this thing on flutter. for that, I am using the flutter inAppWebview plugin.

also, I have tried flutter_webview, WKWebview.

Solution

Please take a look in this documentation for InAppWebView.

JavScriptInterface are normally used to call native methods from webview. I am assuming that the webpage calls the method, so, you have to return the Mac Address as it is presented in the documentation. But you need to change the way for calling the method for flutter by adding this sample(provided in documentation) to you webpage source.

<script>
        window.addEventListener("flutterInAppWebViewPlatformReady", function(event) {
            window.flutter_inappwebview.callHandler('handlerFoo')
              .then(function(result) {
                // print to the console the data coming
                // from the Flutter side.
                console.log(JSON.stringify(result));
                
                window.flutter_inappwebview
                  .callHandler('handlerFooWithArgs', 1, true, ['bar', 5], {foo: 'baz'}, result);
            });
        });
    </script>

Answered By – Eishon

Answer Checked By – Clifford M. (FlutterFixes Volunteer)

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