the first answer which Sergey Alexandrovich Kryukov noted is best and the most sensible way for communicate between apps.
but another way which i use many times is to create a web service or use APIs. (
see this[
^])
the simplest way is using a specific file (for ex a .txt file) in a host which you can read and write data on it by your apps. (this is the worse way for communication and called Pulling in some ways but sometimes can help when we in hurry or amateur!!).
thanks
-amir nasrollahi