How to access outside HTML form data POSTed through a WebView in Android?

Although there are answers on how to access a HTML Form POST data开发者_运维问答 which was displayed in the Webview, I am not able to find an answer that will show how to access it when the HTML Form is from outside or basically not in our control/server/a local file in assets directory?

What I am trying to do here is:

1. Open a simple form (by passing the url to my Webview)
2. Get the form fields and values after user submits it
3. Use it in my android app