whats Context in android

Question

Hi,

Can anyone tell me what's exctly a Context class in android and whats the need of this in android prgramming.. I read about this in developer site.., but unable to understand it clearly.. please help me . Thanks

Answer 1

Putting it simply:

As the name suggests, its the context of current state of the application/object. It lets newly created objects understand what has been going on. Typically you call it to get information regarding another part of your program (activity, package/application)

You can get the context by invoking getApplicationContext(), getContext(), getBaseContext() or this (when in the activity class).

Typical use of context:

• Creating New objects: Creating new views, adapters, listeners:

  TextView tv = new TextView(getContext()); ListAdapter adapter = new SimpleCursorAdapter(getApplicationContext(),..);

• Accessing Standard Common Resources: Services like LAYOUT_INFLATER_SERVICE, SharedPreferences:

  context.getSystemService(LAYOUT_INFLATER_SERVICE)
  getApplicationContext().getSharedPreferences(name, mode);

• Accessing Components Implicitly: Regarding content providers, broadcasts, intent

  getApplicationContext().getContentResolver().query(uri,...);

Answer 2

A Context is a handle to the system; it provides services like resolving resources, obtaining access to databases and preferences, and so on. An android app has activities. It's like a handle to the environment your application is currently running in. The activity object inherits the Context object.

For more information look here at Section 1.3

Answer 3

An Android Context is an "interface" that allows access to application specific resources and class and information about application environment.

If your android app was a web app, your context would be something similar to ServletContext ( I am not making an exact comparison here)

Your activities and services also extend Context to they inherit all those methods to access the environment information in which the app is running.