Question

I am developing a contacts app. I want to add a contact, by opening a new view like this:

RootViewController.m…
it has a NSMutableArray called contacts

- (IBAction)addContact:(id)sender {

    AddContViewController *cont = [[AddContViewController alloc]init];
    [self.navigationController presentViewController:cont animated:YES completion:nil];

}

And then come back and add the contact to the array of the root view controller:

AddContViewController.m

- (IBAction)acceptAction:(id)sender {


    if ([[firstName text] length] < 1 && [[lastName text] length] < 1)
    {
        UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Oh no!" message:@"Invalid contact information!" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles: nil];
        [alert show];
    }
    else{

// create the contact and put it in the root view controller’s array

   Contact *cont = [[Contact alloc]initWithFirstName:[firstName text] lastName:[lastName text] andDOB:[dobPicker date]];

// and now I don’t know what to do….

    [self dismissViewControllerAnimated:YES completion:^{
        UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Success!" message:@"Contact added successfully!" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles: nil];
        [alert show];
        }];
    }
}

Answer 1

There are several ways to pass the data back. I’d suggest setting up a delegate method.
Add this to the top of your AddContViewController.h after any imports:

@class addContViewController
@protocol addContViewControllerDelegate <NSObject>
-(void)addContViewController:(addContViewController *)controller didAddContact:(Contact *)contact;
@end

And after the interface section add

@property (nonatomic, weak) id <addContViewControllerDelegate> delegate;

Then in your RootViewController.h add the protocol to the interface line <addContViewControllerDelegate>
Now in your RootViewController.m method addContact just before you push the new view, add:

cont.delegate = self;

Now in your AddContViewController.m instead of dismissing the view, call:

[self.delegate addContViewController:self didAddContact:cont];

This will call a new method in your RootViewController which it’ll pass the Contact and in here you can do with it want you want, but first dismiss the view:

-(void)addContViewController:(addContViewController *)controller didAddContact:(Contact *)contact {
self dismissViewControllerAnimated:YES;

}