Android

class Start:
    Shows commercial screen.

class Input:
    Input screen.
    Calls Send.

class Send:
    Sends data to server.
    If no match:
        Receives Id from server.
        Try again in background.
    If match:
        Calls Chat.

class Chat:
    Sends and receives messages and data from the server/(other phone).
    Map shows positions, meeting place and points of interest.

class Done:
    Sends all done to server.