Wednesday, September 14, 2011

Android Basics 2

As per  the first step of leaning any thing u have to configure the environment so just follow what is here (i wont go into details of installation) 

Now to the concepts
there are some basic concepts we should have a look at,before going into details

From a developer's perspective, the fundamental building blocks / components of Android are:
1. Activities
2. Services
3. Broadcast Receivers
4. Content Providers.

The means of communication between the above mentioned components is through
1. Intents
2. Intent Filters

The User Interface elements are by using what are called:
1. Views
2. Notifications

Now lets simply define these concepts 

  1. Activity : Activity is the presentation layer for a Android App. in Simple words Activity is the screen visible to user. Every screen in an application is an activity by itself each activity is an independent entity.For Example  A screen Showing Key pad to type the text.
  2. Services : Services are the background tasks/program that can be executed for a a specific task.For example, a service might play music in the background
  3. Broadcast Receiver : Broadcast Receiver is a component that can receive and respond to any broadcast announcements from the system. for example, a broadcast announcing that the battery is low.each broadcast is delivered as an Intent object .(Intentent described below)
  4. Content Provider  : A Content Provider manages application dataou can store the data in the file system, an SQLite database, on the web, or any other persistent storage location your application can access. Through the content provider, other applications can query or even modify the data (if the content provider allows it).
  5. IntentsIntents are the messages passed between the components just like the parameter passed between APIs.mostly Intents are async.
  6. Intent Filters : Intent Filters are the mean through which component advertise their capabilities to do a task/job/operation to ANDROID platform.
  7. View : User Inter face of activities. simply any drwable object used as an element like button and Image etc
  8. Notifications