Objective-C: Example of Passing info from ViewController back to PreviousViewController

seguepass.mm

// AddViewController- has fields where data is entered.
AddViewController.h
@protocol AddDelegate <NSObject>
-(void) saveMySeconds: (int) seconds andTitle: (NSString*)activity;
@end
//AddViewController.m
#pragma mark text field delegate method
-(BOOL)textFieldShouldReturn:(UITextField *)textField { // dismiss keyboard on return.
    [textField resignFirstResponder];
    return YES;
}
- (IBAction)SaveAction:(id)sender {
   NSTimeInterval duration = (NSTimeInterval)TimePicker.countDownDuration;
    NSString * myTitle = ActivityPicker.text;
    int seconds = (int) duration;
        [self.addDelegate saveMySeconds:seconds andTitle: myTitle];
    [self.navigationController popViewControllerAnimated:YES];
}

// SetupViewController.m- This is the previous View Controller
#pragma mark AddDelegate Implementation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    NSLog(@"id %@", [segue destinationViewController]);
    AddViewController *vcb = (AddViewController *)[segue destinationViewController];
    vcb.addDelegate = self;  //key point   
}
// implement saveMySeconds
- (void) saveMySeconds:(int)seconds andTitle:(NSString *)activity {
    NSLog(@"Made It to the delegate implementation");
    NSLog(@"%i, %@", seconds, activity);
    TimerU * u = [[TimerU alloc]init];
    [timer addSegment:u withDuration:seconds andTitle:activity];
    u.remainingInSegment = u.unitDuration;
    myArray = [timer timerArr];
    
    NSLog(@"Count: %i, Array: %@",[myArray count], myArray);
    int totalDuration = [timer calculateDuration];
    NSLog(@"%i", totalDuration);
    NSString * formattedDuration = [self formatSeconds: totalDuration];
    lblTotalCountdown.text = formattedDuration;
    [tblSetup reloadData];
}