Android:How to Update a local XML file when device finds internet connectivity

I am developing an Android application. This application has XML file locally stored within the application apk file. This file contains data to be displayed in the application. I have a latest updated xml file on the server. Now I want to update this file on the device either in background or by notifying user. whenever device finds internet connectivity,it should check the file modification date and should update/replace an old file with the new file from the server.