I want to design a android application and integrate it using API with my website, which is designed in php [closed]

I have created a website using PHP as the backend language and have used databases mySQL through phpmyAdmin. Now i want to develop a mobile application for the same. The front end of the mobile application is written using xml and java(it is a android app). Now what i should do so that both the applications(web and mobile) should use the same database ? Basically i want the two to be integrated. How to do it?