NSNotificationCenter , prints memory address - ios

Question

I have in my app a UITableview Controller, a View Controller and I'm trying to pass NSDictionary from UITableview Controller to my ViewController, using NSNotificationCenter. So, I push a notification at my UITableview Controller and then I add an observer ,using a selector at my ViewController.The selector is called,but I have an NSLog and get memory results ,like :
ViewController: 0x8a0bcc0
I have tried to pass NSString instead of NSDictionary , but I get again memory results , and not the value of the string.
My code :
UITableView Controller
NSString *string=#"This is a test string";
[[NSNotificationCenter defaultCenter] postNotificationName: #"Update" object: string];
ViewController
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(incomingNotification:) name:#"Update" object:nil];
[[NSNotificationCenter defaultCenter] postNotificationName:#"Update" object:self];
And here is the incomingNotification selector method:
-(void) incomingNotification : (NSNotification *)notification{
NSLog(#"Trying to print : %#",[notification object]);
}
All Notifications take place at ViewDidLoad method.Thank you!
UPDATE
Finally , I quit using NSNotificationCenter and used properties to pass data ,changing a bit the inheretence from my TableViewController. No idea why Notifications did not work ,as they were supposed to. Thank you all ,very much for your suggestions and ideas :)

Answer 1

[[NSNotificationCenter defaultCenter] postNotificationName:#"Update" object:self]
Object means the object that generates a notification. To post parameters use another method
[[NSNotificationCenter defaultCenter] postNotificationName:#"Update" object:self userInfo:string]

Answer 2

If I understand correctly, UIViewController is shown after you tap a button on UITableViewController. And you if you are adding a ViewController as observer in its -viewDidLoad:, then it will be able to receive notifications only when it is loaded.
What do you need:
1) override -init or -initWithNibName: method of ViewController like this:
-(id) init
{
self = [super init];
if (self)
{
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(incomingNotification:) name:#"Update" object:nil];
}
return self;
}
so you can be sure ViewController is observing for notifications from the beginning (well, this might be unnecessary step for your case)
2) when you push ViewController you need to send a notification after it was created, like this:
-(void) tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
ViewController *nextController = [[ViewController alloc] initWithNibName:nil bundle:nil];
[self.navigationController pushViewController:nextController animated:YES];
NSString *string=#"This is a test string";
[[NSNotificationCenter defaultCenter] postNotificationName: #"Update" object: string];
}
However, if you're trying just to send some parameters from one view controller to another, this is the wrong way. Just create a property in ViewController and in method -tableView:didSelectRowAtIndex: of UITableViewController set this property