Objective-C – Sending data from NSObject subclass to an UIViewController

Question

I have an UIViewController which has a UITableView inside. In this view controller I want to display some data that I have downloaded from the internet

Answer 1

Your code:

OfficesViewController *ovc = [[OfficesViewController alloc] init];

Creates new instance property of OfficesViewController. Since it's a new instance it does not have a connection to the OfficesViewController you triggered after downloading and parsing process. To be able to comunicate b/w OfficesViewController and OfficesParser create a modified init method for OfficesParser that allows week pointer to the OfficesViewController.

@interface OfficesParser ()

@property(nonatomic,assign)OfficesViewController *ovc;

@end

@implementation OfficesParser

@synthesize ovc;

-(id)initWithDelegate:(OfficesViewController*)delegate{
    ovc = delegate;
    return [self init];
}

Now you can access your ovc delegate.

- (void)queueFinished:(ASINetworkQueue *)queue {
    NSArray *offices = [self offices];
    [ovc setOffices:offices];
}

Finally create your OfficesParser like that

self.officesParser = [[OfficesParser alloc] initWithDelegate: self];

Answer 2

You need to take a look at delegates and protocols. They're exactly what you're looking for, as they let classes communicate without having to persist a reference. Here is another explanation on them.