Accessing parent view controller (custom) properties

Question

I have written a UITabBarController subclass (called MainViewController) and added a few instance variables, specifically a venue of type Venue. Ea

Answer 1

You're doing something completely wrong. parentViewController is declared as a UIViewController. NSLoging it outputs its real type due to the wonders of polymorphism.

UIViewController doesn't have a Venue member. Your MainViewController does. Casting it is, in fact, the right answer. Make sure to import MainViewController.h as well.

#import "MainViewController.h"
[...]
NSString *name = ((MainViewController *)self.parentViewController)).venue.name;

Also make sure, of course, that venue is declared as a @property of MainViewController, and name is a @property of Venue.

Answer 2

Your NSLog() statement is "seeing" it as a MainViewController because that's what the object actually is. The problem you're having though, is that the compiler doesn't actually realize this because the parentViewController property is declared as a plain old UIViewController. Even though you're actually returning a subclass of it, as far as the compiler knows you're trying to call that method on a UIViewController, and it's going to complain. Casting it to a MainViewController will solve the issue.

Answer 3

int currentVCIndex = [self.navigationController.viewControllers indexOfObject:self.navigationController.topViewController];

//previous view controller
AccountViewController *account = (AccountViewController *)[self.navigationController.viewControllers objectAtIndex:currentVCIndex - 1];

account.property = object;
[account doSmthng];