What is the proper way to implement MVC pattern in iOS app?

I'm trying to make a clear MVC project. So is it good or bad idea to use NSNotificationCenter's observers for communication between UIViews and ViewControllers?

For example in custom CustomView.m i make a button:

- (void) makeSomeButton{
....
 [bt addTarget:self action:@(buttonWasClicked) forControlEvents:UIControlEventTouchDragInside];
...
}

- (void) buttonWasClicked {
    [[NSNotificationCenter defaultCenter] postNotificationName:@"buttonWasClicked" object:nil];
}

And in the viewCotroller.m i'm adding observer in init section:

- (void)viewDidLoad {  // 
       [self.view addSubview: [[CustomView alloc] initWithFrame ...]];     
       .....
         [[NSNotificationCenter defaultCenter] addObserver:self
         selector:@(buttonWasClicked) name:@"buttonWasClicked" object:nil];
       .....
    }

    then 
    - (void) buttonWasClicked{
     // button was clicked in customView so do something 
    }

If it's not correct, please, explain what is the proper way to implement MVC pattern in iOS app?