how retrieve a web page by sending login credentials via POST method in android studio

I am trying to create an app which has a custom login page. It takes username and password as input strings. When i click a button called "login", it should retrieve the contents of the page of corresponding username and password and load it to a webview. The actual website uses POST method to send the credentials and load the page. I searched a lot. But couldn't find a proper answer. How do i do this in android studio.