Regularly refresh the background to execute an operation.

A blog today on GCD: http://blog.devtang.com/blog/2012/02/22/use-gcd/

Set a timer in the main thread to regularly execute an operation.

-(Bool) Application :( uiapplication *) Application didfinishlaunchingwitexceptions :( nsdictionary *) launchoptions

{

[Self
Startatimer];

}

-(Void) startatimer {

[Nstimer
Scheduledtimerwithtimeinterval: 1.0
Target: Self
Selector: @ selector (getnewsession :)
Userinfo: Nil
Repeats: Yes]; // This is the main thread.

}

-(Void) getnewsession :( nstimer *) thetimer {

[Self
Performselectorinbackground: @ selector (didnewsession)
Withobject: Nil];

}

-(Void) didnewsession

{

// A new thread is set for execution.

@ Autoreleasepool {

Dlog (@ "timer get new seesion ");

// If you want to update the UI of the main thread, execute this

[Self
Performselecw.mainthread: @ selector (refreshui)
Withobject: Nil
Waituntildone: Yes];

}

}

-(Void) refreshui

{

}