How to pass userInfo in NSNotification?

I am trying to send some data using NSNotification but get stuck. Here is my code:

// Posting Notification
NSDictionary *orientationData;
if(iFromInterfaceOrientation == UIInterfaceOrientationLandscapeRight) {
	orientationData = [NSDictionary dictionaryWithObject:@"Right"
                                                  forKey:@"Orientation"];
}

NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];
[notificationCenter postNotificationName:@"Abhinav"
                                  object:nil
                                userInfo:orientationData];

// Adding observer
[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(orientationChanged)
                                             name:@"Abhinav"
                                           object:nil];

Now how to fetch this userInfo dictionary in my selector orientationChanged?

You get an NSNotification object passed to your function. This includes the name, object and user info that you provided to the NSNotificationCenter.

- (void)orientationChanged:(NSNotification *)notification
{
	NSDictionary *dict = [notification userInfo];
}

Your selector must have : to accept parameters.
e.g.

@selector(orientationChanged:)

then in the method declaration it can accept the NSNotification parameter.

You are posting the notification correctly. Please modify the Notification Observer like following.

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(orientationChanged:)
 name:@"Abhinav" object:nil];

- (void)orientationChanged:(NSNotification *)notification
{
    NSDictionary *dict = [notification userInfo];
}

I hope, this solution will work for you..

In swift To get userinfo object

     let dict = notification.userInfo
     print(dict)