Question

In my app there are two tabbars. In tab-0 parent class is “FirstViewController” and in tab-1 parent class is “SecondViewController”. In “SecondViewController” i have declared protocol and custom delegate method. i want to pass the information in “FirstViewController”(FVC). So FVC has to assigned as a delegate.

Now my doubt is, right now i am in “SVC”. How can i assign “FVC” as a delegate of “SVC”?

In “SVC”

[[self delegate] sendCoordinates:self];

Definition of method is in “FVC”. To execute this method, first i need to assign “FVC” as a delegate.

I hope I am clear in explaining my problem.

Thanks in advance.

Answer 1

You need to set the delegate. Let me demonstrate:

`SVC.h`

@interface SVC
{
    id _delegate;
}

- (void)setDelegate:(id)delegate; //sets the delegate
- (id)delegate; //gets the delegate

@end

@protocol SVCDelegate

- (void)sendCoordinates:(SVC *)svc;

@end

Then, in SVC.m, you call the delegate in exactly the same way as you showed in your question, so [[self delegate] sendCoordinates:self];

Now, in FVC, you’ll need to #import SVC.h and initialise the object.

SVC*svcObject = [[SVC alloc] init];
[svcObject setDelegate:self]; //self now refers to FVC - I think you're missing this one
//work with the object and when you're done, get rid of it in dealloc:
[svcObject setDelegate:nil];
[svcObject release];

In the same class, implement - (void)sendCoordinates:(SVC *)svc and it will be called after you set the delegate.

I think you’re missing the setDelegate: stage, which is why it doesn’t work.

Hope it helps!

Note: In SVC, remember to retain the delegate, or it will become nil and no delegate methods will never be called. Don’t forget to release that delegate once you’re done.