Fetch form data of webview in android application

I am creating a sample app for facebook in Android using the facebook SDK.

I am using the default login approach, where the user is shown a webview with the Facebook login page. The user enters the credentials here & is authenticated.

Now if the开发者_StackOverflow社区 login is successful, i want the username & password entered on the login page of webview in my android app.

How to achieve this?

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Please don't do this! I hope that this isn't available and grabbing this would be in violation of the Facebook terms of service. The whole point of oauth is so developers don't have access to your email address and password.