Question

I am aware that this topic has been covered already in many places, but while going through the different answers, I could not find a solution that fits my case.

Basically what I am trying to do is very simple. I have a view controller with a table view, and a + button that fires a second view controller where the user can enter, say a name, and this name is then added to the first view controller table view. Think about Contacts on the iPhone where you can add a new person (or Amazon where you can add a new credit card).

My question is – what is the best way to return this string (in this case) back to the view controller where the table is?

People suggested using NSDefaults, Delegate, or singleton none of which are really good for this case (each one for its own reason). I really just need to return a simple string.

Thank you for your help.

Answer 1

Here’s what you need to do (please note I am typing this off the top of my head so the compiler may have some issues with my syntax).

In your child view controller interface:

@protocol ChildDelegate <NSObject>
- (void)didConfirmName:(NSString*)name
@end

@interface ChildViewController : UIViewController
...

@property (nonatomic, assign) id<ChildDelegate> delegate;

And implementation, inside the method called when the user confirms whatever they need to confirm:

- (void)myCustoMethod
{
    ...
    if ([self.delegate respondsToSelector:@selector(didConfirmName:)])
        [self.delegate didConfirmName:NAME_STRING];
}

And in your parent view controller, when you are instantiating the child view controller, assign SELF as the delegate:

ChildViewController *vc = [[ChildViewController alloc] init...];
vc.delegate = self;

And implement:

- (void)didConfirmName:(NSString*)name
{
    // Do whatever you want with the name here...
}

Also make sure you tell the compiler that you are implementing the protocol :

@interface ParentViewController () <ChildDelegate>
@end