What are alternatives to “delegates” for passing data between controllers?

Question

Are there alternatives to \"delegates\" to pass back data from one controller to another?

Just seems like a lot of work implementing a delegate just to pass back the

Answer 1

You could use many ways:

1. Calling a method of the super controller, needs casting maybe
2. Notifications
3. Simple Key-Value-Observing
4. Core Data

Example for for 1.

interface of your MainViewController: add a public method for the data to be passed

- (void)newDataArrivedWithString:(NSString *)aString;

MainViewController showing ChildController

- (void)showChildController
{
    ChildController *childController = [[ChildController alloc] init];
    childController.mainViewController = self;

    [self presentModalViewController:childController animated:YES];

    [childController release];
}

Child Controller header / interface: add a property for the mainViewController

@class MainViewController;

@interface ChildController : UIViewController {
    MainViewController *mainViewController;   
}

@property (nonatomic, retain) MainViewController *mainViewController;

Child Controller passing data to the MainViewController

- (void)passDataToMainViewController
{
    NSString * someDataToPass = @"foo!";
    [self.mainViewController newDataArrivedWithString:someDataToPass];
}