Android.............!!

• its an mobile application software stack
• has O.S(linux), library's, Dalvik virtual system,Framework,Application.
• we write our program(application) on framework in Java.  

 Android components

1. Activity  ---------------------- Each screen in android with which we can interact is an activity.
2. Services ----------------------Its the task that runs at the background even without user interaction                   
3. Content provider--------------It provides or shares information with other application.
4. Broadcast Receiver-----------It gives all announcements.
5. Intent-------------------------Forms a connection between components except with content provider.
6. Manifest file------------------ Keeps overall information of its components.

 View------All small small rectangular boxes that we see on the screens are views.
                  -  like we see edit text box,button box,ckeck box etc

Functions  used

1. onCreate()----------first function is called first by activity .
2. setContentView()---to set final design screen on the top of graphical window.
3. Toast.makeText(getApplicationContext(),"Text",duration)----prints text on screen,its like println in java.