ios - Updating UIView with data of another Class -

i have classa , classb, want pass data classb , update existing uiview of instance of classa.

what i'm doing instantiating classa in classb , calling updatelabel:

classa *obj = [[classa alloc] init]; [obj updateview:value]; 

it's not working ! think because updatelabel called on instance of classa uiview nil. right?

what way make work?

ps: i'm doing way because value update set when method of classb triggered.

if want update data in class can use nsnotificationcenter or delegate

in class @ time of initialisation.

-(void)viewdidload{       [[nsnotificationcenter defaultcenter] addobserver:self selector:@selector(labelupdate:) name:@"noficationname" object:nil]; }  -(void)labelupdate:(id)sender{      //do update stuff. } 

call in class b when want update class

[[nsnotificationcenter defaultcenter] postnotificationname:@"noficationname" object:nil];