Components Continue


 ACTIVITY:It is a window that provides User Interface to User's Applications.
Activity must be decalred in Android mainfest.xml file.Activity may be one or more than one.


Lifecycle of AnDROID


The Activity base class defines a series of events that governs the life cycle of an activity. The Activity
class defines the following events:
 onCreate() — Called when the activity is first created
 onStart() — Called when the activity becomes visible to the user
 onResume() — Called when the activity starts interacting with the user
 onPause() — Called when the current activity is being paused and the previous activity is
being resumed
 onStop() — Called when the activity is no longer visible to the user
 onDestroy() — Called before the activity is destroyed by the system
 onRestart() — Called when the activity has been stopped and is restarting again

2.Services
 It is a Building block but its not a user interface as an Activity.Services is mainly a program that runs in a background for an indefinite period.

3.Broadcast Recivers
They recieve and respond to all broadcast Annoncements.

4.Content Providers
They expose a specific set of data to applications.

Most important:

All these Components are communicate with each other with the help of
INTENT and INTENT FILTERS