Multiple NSNotificationCenter Issue - ios

Question

In my app in which I'm using storyboards I have mainViewController with MapView inside. At the top of the mainViewController I'm displaying UIContainerView from the bottom of the screen with UITableViewController inside. When user click on row I'm sending notification to the mainViewController in purpose of changing map region with animation. The similar notifications are sending when user is selecting specific tableViewCell and also when user tapping on the DONE button located in navigationViewController. Everything works fine for me except method called in DONE button method.
MAIN VIEW CONTROLLER -(void)viewDidLoad method...
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(hideContainerView:)
name:HideContainerView object:self];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(changeRegionForUser:)
name:ChangeRegionForUser
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(hideContainerView:)
name:ChangeRegionToInitial
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(changeRegionToFitWearerAnnotations:)
name:ChangeRegionToFitWearerAnnotations
object:nil];
MAIN VIEW CONTROLLER OBSERVERS METHODS:
#pragma mark NSNotificationCenter methods
-(void)changeRegionForUser:(NSNotification*)notification
{
NSLog(#"%#",notification.description);
[self zoomToFitUserLocationWithLatitude:-33.861858 longitude:151.210546 andUserInfo:nil];
}
-(void)hideContainerView:(NSNotification*)notification
{
NSLog(#"%#",notification.description);
[self zoomToFitMapAnnotations:_mainMapView];
[UIView beginAnimations:#"HideContainerAnimation" context:nil];
[UIView setAnimationDuration:0.5];
[_containerView setFrame:CGRectMake(0, 600, 320, 284)];
[UIView commitAnimations];
}
-(void)changeRegionToFitWearerAnnotations:(NSNotification*)notification
{
NSLog(#"%#",notification.description);
[self zoomAnnotationsOnMapView:_mainMapView toFrame:CGRectMake(0, 0, 320, 200) animated:YES];
}
TABLE VIEW CONTROLLER (DID-SELECT-ROW-AT-INDEX-PATH METHOD)//It work properly
[[NSNotificationCenter defaultCenter] postNotificationName:#"ChangeRegionForUser" object:self];
TABLE VIEW CONTROLLER (DONE BUTTON METHOD) //IT DOESN'T WORK
-(void)doneButtonAction:(id)sender
{
[[NSNotificationCenter defaultCenter] postNotificationName:#"HideContainerView" object:self];
}
MY STORYBOARD
IN MAIN VIEW CONTROLLER.H
#interface MainScreenViewController : UIViewController<MKMapViewDelegate>
extern NSString * const HideContainerView;
extern NSString * const ChangeRegionForUser;
extern NSString * const ChangeRegionToInitial;
extern NSString * const ChangeRegionToFitWearerAnnotations;
IN MAIN VIEW CONTROLLER.M
#import "MainScreenViewController.h"
NSString* const HideContainerView = #"HideContainerView";
NSString* const ChangeRegionForUser = #"ChangeRegionForUser";
NSString* const ChangeRegionToInitial = #"ChangeRegionToInitial";
NSString* const ChangeRegionToFitWearerAnnotations =#"ChangeRegionToFitWearerAnnotations";

Answer 1

You are using a string constant HideContainerView for the notification name when you add yourself as observer. But when you post the notification you are using a literal string #"HideContainerView". Maybe you are using two different strings there?
Also, I think that you are using self as the object when you add yourself as an observer. It seems this precludes receiving the notification. From the documentation:
notificationSender
The object whose notifications the observer wants to receive; that is, only notifications sent by this sender are delivered to the observer.
If you pass nil, the notification center doesn’t use a notification’s sender to decide whether to deliver it to the observer.
Use nil instead.
That being said, would it not be better to couple these two controllers more tightly. I think that would be a much more appropriate design. You should send notifications when the sender does not know if the receiver exists or not. But in this case, you know that the receiver exists.
Thus, you should implement a simple delegate protocol, retain a reference to the map view controller and tell it directly what to do.