Maybe a little late answer, but I'd like to share some method you can use.
- Set a fixed user-agent in Android app, for example you can set user-agent in Android Java with the code below:
webView.getSettings().setUserAgentString("Enter here user-agent string")
- Check user-agent in backend of website (you can use $_SERVER['HTTP_USER_AGENT'] in PHP to get user agent), if the user-agent is equal to your fixed user agent, do not show ads.