objective c delegate understanding - objective-c

Question

I have a class ApiClient which gets some data from a server using NSURLConnection and sends it back to its delegate
I have another class called Fetcher.h that calls some function on ApiClient and implements the delegate method in it.
I have a third class (View Controller) that calls the Fetcher.h executeCall() and triggers the whole process.
Fetcher *fetcher = [[Fetcher alloc] init];
[fetcher getData];
If I call the ApiClient code directly in the View controller, it works fine. Why wont it work from the Fetcher class? What am I doing wrong?
Within the Fetcher getData I have this code
APIClient* client = [APIClient sharedInstance];
[client setDelegate:self];
[client getData];
Thanks in advance.

Answer 1

It is possible that since you are not assigning the Fetcher object you are creating in the viewcontroller to any property or anything, it is getting released at the end of whatever method you are allocating it in. Try adding this to your viewcontroller:
.h
#interface ViewController
#property (strong, nonatomic) Fetcher *myFetcher; //Add this line in your view controller's interface
...
.m
#implementation ViewController
#synthesize myFetcher;
...
Fetcher *fetcher = [[Fetcher alloc] init];
[fetcher getData];
self.myFetcher = fetcher;//Add this line in your code as well

Answer 2

Try this...
#protocol APIClientProtocol <NSObject>
#optional
- (void) handleMessage;
#end
#interface APIClient : NSObject
#property (readwrite, nonatomic, strong) id<APIClientProtocol> delegate;
#end
#implementation APIClient
#synthesize delegate;
- (void) someAPIClientWork
{
// Do some client work here
if ( [self.delegate respondsToSelector:#selector(handleMessage)] )
[self.delegate performSelector:#selector(handleMessage)];
}
#end
.h of Fetcher
#interface Fetcher : NSObject <APIClientProtocol>
#end
.m of Fetcher
#implementation Fetcher
- (void) someInit
{
APIClient *client = [APIClient sharedInstance];
client.delegate = self;
}
- (void) handleMessage
{
// Something in APIClient was called
}
#end