Error calling method on NPObject! in Android 2.2

Question

I\'m using addJavascriptInterface within my Android application to allow JavaScript to invoke functions I\'ve created in my native Java application.

This worked well

Answer 1

Here's a twist I found on this problem that could be useful for some of the folks running into this problem (and it likely explains intermittent failures that seem to defy explanation)...

If any exceptions are thrown (and not caught) in the return handler code prior to allowing the javascript interface callback to return clean, it will propagate back as a failed call and you will also get this error - and it would have nothing to do with missing functions or parameters.

The easiest way to find this case (whether or not you use this in your final implementation) is to push whatever handler code you have back onto the UI thread (the callback will not be on the UI thread) - this will allow the callback to return clean and any subsequent exceptions that occur will propagate properly up until you catch them or until the app crashes. Either way you will see exactly what is really happening. Otherwise the uncaught exception passes back to javascript where it will not be handled or reported in any way (unless you specifically built error trapping code into the JS you were executing).

Good Luck All.

bh