Password Reset through Email in android with php mysql database via json

I'm new in android and this is my first app and I'm developing an app now with a forgot password in it. In able to access the full feature of the system, the user must login first. When the user click the Forgot Password, it goes to the Forgot Password Activity. In that activity, there's an EditText for email address and a Send button. What I'd like to happen is that, when the user fill-out the email address EditText and click the Send Button, the password will automatically be sent to the email inputted by the user. How can I code it in Android?
i am using mysql database.please help me.thanks in advance.