a few days ago, my friend come to me and ask if i want to help him creating Android application. i haven't done any Android because I'm still busy with PHP projects. but i said okay, i just hope its a pretty simple application. That's the story behind, and these are the requirements for the Android App. The Android Application is an offline catalog products that can be updated through local/wifi connection. the client it's self already handed the User Interface that he want to build. The problem exists not only in Synchronize data from server through wifi but also the database on their server.