How do you pass data between views using a UINavigationController

Question

I have tried using the obvious method as outlined in the following example but my passed variable (rootcategory) is still nil on viewDidLoad in the loaded view

http://www.iphonesdkarticles.com/2008/08/table-view-tutorial-part-3.html

This is my code:

CategoryViewController *viewController = [[CategoryViewController alloc] initWithNibName:@"CategoryViewController" bundle:[NSBundle mainBundle]];
self.categoryViewController.rootCategory = @"433";
self.categoryViewController = viewController;
[viewController release];

I am synthesizing a property in the header as follows:

@property (nonatomic, readwrite) NSString *rootCategory;

Answer 1

What does your header file for CategoryViewController look like? Did you define rootCategory as a property? Is it synthesized or did you write your own setter and getter?

Answer 2

You are allocating viewController, and try to change self.categoryViewController before it is assigned to viewController.

CategoryViewController *viewController = [[CategoryViewController alloc] initWithNibName:@"CategoryViewController" bundle:[NSBundle mainBundle]];
viewController.rootCategory = @"433";
self.categoryViewController = viewController;
[viewController release];

should work.

Answer 3

I believe that viewDidLoad is called on the new instance before initWithNibName: returns, so you'd be setting your properties after it's called.