How to use keyboard notification to adjust view when keyboard is about to show or hide

KeyboardHandler.m

- (void)viewDidAppear:(BOOL) animated {
    [super viewDidAppear:animated];
    
    // Register notification when the keyboard will be show
    [[NSNotificationCenter defaultCenter] addObserver:self 
                                             selector:@selector(keyboardWillShow:)
                                                 name:UIKeyboardWillShowNotification
                                               object:nil];

    // Register notification when the keyboard will be hide
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillHide:)
                                                 name:UIKeyboardWillHideNotification
                                               object:nil];
}

- (void)keyboardWillShow:(NSNotification *)notification {
    
    NSTimeInterval animationDuration;
    UIViewAnimationCurve animationCurve;
    CGRect keyboardBounds;
    
    [[notification.userInfo valueForKey:UIKeyboardAnimationDurationUserInfoKey] getValue:&animationDuration];
    [[notification.userInfo valueForKey:UIKeyboardAnimationCurveUserInfoKey] getValue:&animationCurve];
    [[notification.userInfo valueForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardBounds];
    
    [UIView animateWithDuration:animationDuration delay:0 options:animationCurve animations:^{
    
    } completion:^(BOOL finished) {
    
    }];
}

- (void)keyboardWillHide:(NSNotification *)notification {
      
    NSTimeInterval animationDuration;
    UIViewAnimationCurve animationCurve;
    CGRect keyboardBounds;
    
    [[notification.userInfo valueForKey:UIKeyboardAnimationDurationUserInfoKey] getValue:&animationDuration];
    [[notification.userInfo valueForKey:UIKeyboardAnimationCurveUserInfoKey] getValue:&animationCurve];
    [[notification.userInfo valueForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardBounds];
    
    [UIView animateWithDuration:animationDuration delay:0 options:animationCurve animations:^{
    
    } completion:^(BOOL finished) {
    
    }];
}

- (void)dealloc{
    
    [[NSNotificationCenter defaultCenter] removeObserver:self];
    
}

// Tutorial: http://spin.atomicobject.com/2014/01/08/animate-around-ios-keyboard/