Could someone please summaries difference between each type of Module and their uses:
Activity Module
Class Module
Code Module
Service Module
Activity Module is a UI module, in which you can manipulate the screen and different controls. Each activity controls 1 "screen" or form, and you can have as many as you need.
Class module is a reusable class. i.e. you can create a custom control using a class and use it (several references to it) in many forms. A class can also deal with events triggered from the controls used in the class.
Code module can be used as a "commonly used" code repository... Imagine you have a long calculation to do several times in your app... You create a code module with that calculation and you call it from whichever class or activity you which. Code modules cannot interact directly with the UI.
Service module is like a listener.. it gets executed at appstart and stays active untill either the OS or your app kills it. It is usually used to wait for external events, like incoming notifications and such.