Changes

The activities, services and broadcast receivers are activate through '''intents''' that are instances of the [http://developer.android.com/reference/android/content/Intent.html Intent] object. The Intent is a message define defined by a data structure [http://developer.android.com/guide/topics/intents/intents-filters.html holding an abstract description of an operation to be performed]  an example of an application that illustrates the usage of an Intent.