keyboard notif

- (void)registerKeyboardNotifications {
    NSNotificationCenter *dnc = [NSNotificationCenter defaultCenter];
    [dnc addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
    [dnc addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];

    [dnc addObserver:self selector:@selector(keyboardDidShow:) name:UIKeyboardDidShowNotification object:nil];
    [dnc addObserver:self selector:@selector(keyboardDidHide:) name:UIKeyboardDidHideNotification object:nil];
}

- (void)unregisterKeyboardNotifications {
    NSNotificationCenter *dnc = [NSNotificationCenter defaultCenter];
    [dnc removeObserver:self name:UIKeyboardWillShowNotification object:nil];
    [dnc removeObserver:self name:UIKeyboardWillHideNotification object:nil];
    [dnc removeObserver:self name:UIKeyboardDidShowNotification object:nil];
    [dnc removeObserver:self name:UIKeyboardDidHideNotification object:nil];
}

- (void)keyboardWillShow:(id)notification {
    NSDictionary* keyboardInfo = [notification userInfo];
    CGFloat keyboardHeight = [[keyboardInfo objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size.height;
}

- (void)keyboardWillHide:(id)notification {
}

- (void)keyboardDidShow:(id)notification {

}

- (void)keyboardDidHide:(id)notification {

}