Sending AsynchronousRequest with a block-the right way - objective-c

Question

In my app i am sending a request to server .
The request is in some other class-called requestClass, and is being called from the main view class. (i am using cocos2d).
My question is, how would i informed the main class (from the requestClass ) that the operation is done ?
When it finish the request-its callback is in its own class(requestClass) and the NSLog is done IN the requestClass .
i dont think NSNotification is the right way
requestClass is like :
[NSURLConnection
sendAsynchronousRequest:request
queue:[[NSOperationQueue alloc] init]
completionHandler:^(NSURLResponse *response,
NSData *data,
NSError *error)
{
if ([data length] >0 && error == nil)
{
**// HOW SHOULD I INFORM THE CLASS THAT CALL ME NOW ???**
}
else if ([data length] == 0 && error == nil)
{
NSLog(#"Nothing ");
}
else if (error != nil){
NSLog(#"Error = %#", error);
}
}];

Answer 1

OK, to write a delegate protocol...
Assuming your connection file is called MyRequestClass.
In MyRequestClass.h...
#protocol MyRequestClassDelegate <NSObject>
- (void)requestDidFinishWithDictionary:(NSDictionary*)dictionary;
//in reality you would pass the relevant data from the request back to the delegate.
#end
#interface MyRequestClass : NSObject // or whatever it is
#property (nonatomic, weak) id <MyRequestClassDelegate> delegate;
#end
Then in MyRequestClass.h
[NSURLConnection
sendAsynchronousRequest:request
queue:[[NSOperationQueue alloc] init]
completionHandler:^(NSURLResponse *response,
NSData *data,
NSError *error)
{
if ([data length] >0 && error == nil)
{
[self.delegate requestDidFinishWithDictionary:someDictionary];
//you don't know what the delegate is but you know it has this method
//as it is defined in your protocol.
}
else if ([data length] == 0 && error == nil)
{
NSLog(#"Nothing ");
}
else if (error != nil){
NSLog(#"Error = %#", error);
}
}];
Then in whichever class you want...
In SomeOtherClass.h
#import "MyRequestClass.h"
#interface SomeOtherClass : UIViewController <MyRequestClassDelegate>
blah...
In someOtherClass.m
MyRequestClass *requestClass = [[MyRequestClass alloc] init];
requestClass.delegate = self;
[requestClass startRequest];
... and make sure to write the delegate function too...
- (void)requestDidFinishWithDictionary:(NSDictionary*)dictionary
{
//do something with the dictionary that was passed back from the URL request class
}