Question

I have a requirement that my app, can receive events (e.g. messages) from server any time (even if app is not running). So do I need to create an infinitely running service to listen for these events?

This to me seems similar to Email apps in Smartphones, like whenever you receive a new email(event in my case), its able to show notifications and also able to update my list adapter whenever I receive an event.

But I dun know how will I implement this?

Answer 1

You should take a look at C2DM (push-messages):
http://code.google.com/intl/sv-SE/android/c2dm/index.html#intro
it allows a server to send messages to devices at any time.

From the link:

Here are the primary characteristics of Android Cloud to Device
Messaging (C2DM):

It allows third-party application servers to send lightweight messages to their Android applications. The messaging service is not
designed for sending a lot of user content via the messages. Rather,
it should be used to tell the application that there is new data on
the server, so that the application can fetch it.
[…]
An application on an Android device doesn’t need to be running to
receive messages. The system will wake up the application via Intent
broadcast when the the message arrives, as long as the application is
set up with the proper broadcast receiver and permissions.
[…]