Uikeyboardwillhidenotification method call twice on scroll

I have a view with a UIScrollView and I have a lot UITextField

I close the keyboard when I touch the view and it works fine at the same time when I want to close the keyboard when I view the view. My problem is when I view the view that closes the keyboard, but it calls the (keyboardWillHide) method twice, which makes the problem related to the wrong screen setting. How can I prevent the method from being called twice?

My code:

- (void)viewDidLoad {
   [super viewDidLoad];

  UITapGestureRecognizer* tapGesture = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(closeTextInput)];
tapGesture.cancelsTouchesInView = NO;
  [self.view addGestureRecognizer:tapGesture];

  _scrllView.keyboardDismissMode = UIScrollViewKeyboardDismissModeOnDrag;
}

- (void)viewWillAppear:(BOOL)animated
{
  [super viewWillAppear:animated];

  [[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(keyboardWillHide)
                                             name:UIKeyboardWillHideNotification
                                           object:nil];
}

- (void)viewWillDisappear:(BOOL)animated
{
  [super viewWillDisappear:animated];

  [[NSNotificationCenter defaultCenter] removeObserver:self
                                                name:UIKeyboardWillShowNotification
                                              object:nil];

  [[NSNotificationCenter defaultCenter] removeObserver:self
                                                name:UIKeyboardWillHideNotification
                                              object:nil];
}

-(void)keyboardWillHide {

    if (self.view.frame.origin.y >= 0)
    {
        [self setViewMovedUp:YES];
    }
    else if (self.view.frame.origin.y < 0)
    {
        [self setViewMovedUp:NO];
    }
}

-(void)setViewMovedUp:(BOOL)movedUp{

    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.3];

    CGRect rect = self.view.frame;
    if (movedUp)
    {
        if (self.view.frame.origin.y != -kOFFSET_FOR_KEYBOARD){

        rect.origin.y -= kOFFSET_FOR_KEYBOARD;
        rect.size.height += kOFFSET_FOR_KEYBOARD;
      }
  }
  else
  {
        rect.origin.y += kOFFSET_FOR_KEYBOARD;
        rect.size.height -= kOFFSET_FOR_KEYBOARD;
  }
        self.view.frame = rect;
        [UIView commitAnimations];
}