ios4 - Performing background task in an app on iphone -

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ios4 - Performing background task in an app on iphone -

i want app poll server updates , download them when app running in background. how can accomplish this. can tell me start from?

any help appreciated.

generally, apple wants utilize push, not pull, because conserves battery life. however, if want go polling, there things into. apple documentation describes background tasks in depth here. (note may need registered developer see it. sounds though.) particularly, want utilize these methods:

applicationwillresignactive:

applicationdidenterbackground:

applicationwillenterforeground:

beginbackgroundtaskwithexpirationhandler:

ios4

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