pass NSString variable to other class with NSNotification - objective-c

Question

I want to pass a NSString from one class to another class and add that NSString to an NSMutableArray in my second class. I'm believe i can use NSNotification for this, but i don't know how to pass an variable over notification. My code would something like this:
//class1.h
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController
#property(strong,nonatomic)NSString *variableString;
#end
//class1.m
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
#synthesize variableString = _variableString;
- (void)viewDidLoad
{
[super viewDidLoad];
[self setVariableString:#"test"];
[[NSNotificationCenter defaultCenter] postNotificationName: #"pasteString" object: _variableString];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
}
#end
//class2.h
#import <UIKit/UIKit.h>
#interface ViewController2 : UIViewController
#property(strong,nonatomic)NSMutableArray *arr;
#end
//class2.m
#import "ViewController2.h"
#interface ViewController2 ()
#end
#implementation ViewController2
#synthesize arr = _arr;
- (void)viewDidLoad:(BOOL)animated
{
[super viewDidLoad];
if(_arr == nil)
{
_arr = [[NSMutableArray alloc]init];
}
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(incomingNotification:) name:#"pasteString" object:nil];
// Do any additional setup after loading the view.
}
- (void) incomingNotification:(NSNotification *)notification{
NSString *theString = [notification object];
[_arr addObject:theString];
}
#end

Answer 1

In sender class you can post a notification with an object with something like this:
[[NSNotificationCenter defaultCenter] postNotificationName: NOTIFICATION_NAME object: myString];
The listener or receiver class has to register for the notification:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(incomingNotification:) name:NOTIFICATION_NAME object:nil];
The method incomingNotification is:
- (void) incomingNotification:(NSNotification *)notification{
NSString *theString = [notification object];
...
}
EDIT
When you post the notification from "ViewController", is "ViewController2" loaded?

Answer 2

Send your Notification like this:
if(isComingFromHowToUseThisApp) {
[[NSNotificationCenter defaultCenter] postNotificationName:#"noteFromVideoPlayer"
object:#"fromHowToUseThisApp"];
}else {
[[NSNotificationCenter defaultCenter] postNotificationName:#"noteFromVideoPlayer"
object:#"fromVideoPlayerViewiPad"];
}
Receive your notification like this:
// Reset the default value of table view in master split view
- (void)defaultCellSelectionOfTableView:(NSNotification *) objNotification {
// We need to change the default selection of row
NSString *noticeFromVideoPlayer = [objNotification object];
}// end defaultCellSelectionOfTableView