Android webview custom JS not get message from postMessage call

Question

I use my nodejs server with passport to provide 3rd party auth. I setup a WebView on my Anrdroid client to load the following html:

<!DOCTYPE html>
<html>
<head>
    <script src="file:///android_asset/oauth.js" type="text/javascript"></script>
</head>

<body>
</body>

</html>

With this javascript:

Android.callit('Loaded javascript file');

window.addEventListener('message', function(event) {
  Android.callit('got message event');

  authWindow.close();
}, false);

var authWindow = window.open("https://myserver/twitter/signin", "");

After successful auth to a third party server my nodejs server redirects to a page like this:

<html>
  <head>
    <script>window.opener.postMessage({"auth":true}, '*');</script>
  </head>
  <body>
  </body>
</html>

Here is my Activity that starts the webview:

public class OAuthActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.oauth);

        WebView webView = (WebView) findViewById(R.id.webView);
        webView.getSettings().setJavaScriptEnabled(true);
        webView.getSettings().setJavaScriptCanOpenWindowsAutomatically(true);
        webView.addJavascriptInterface(new JSInterface(), "Android");
        webView.setWebViewClient(new WebViewClient() {
            public void onReceivedSslError(WebView webView, SslErrorHandler handler, SslError error) {
                handler.proceed();
            }

            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                view.loadUrl(url);
                return true;
            }
        });

        webView.loadUrl("file:///android_asset/oauth.html");
    }

    public class JSInterface {
        @JavascriptInterface
        public void callit(String with) {
            Log.i("TEST", with);
        }
    }
}

So why is the 'message' event never firing?

As a note I have done this in a browser and it works fine. Just not when I try and use it in an android webview.

Did you manage to solve this? I'm stuck on the same problem. I'm using postMessage to implement crossPageChannel communication (using Google Closure) and I see the postMessage calls but the 'message' event isn't firing — Kesty, Oct 22 '15 at 11:57

score 1 · Answer 1 · edited Jan 24 '20 at 12:29

1

Above code will work fine if you add escape characters in above JSON as

window.opener.postMessage({\"auth\":true}, \"*\");

edited Jan 24 '20 at 12:29

Ajay Sivan

2,807
2
32
57

answered Jan 07 '20 at 17:59

Kashif Ilyas

136
1
2
7

Here's a comprehensive example complete with a download link to a working example: https://stackoverflow.com/questions/41753104/how-do-you-use-webmessageport-as-an-alternative-to-addjavascriptinterface/60292598#60292598 – user2288580 Feb 28 '20 at 08:15

Android webview custom JS not get message from postMessage call

1 Answers1