quickadd.m

self.keyboardObserver = [[NSNotificationCenter defaultCenter] addObserverForName:UIKeyboardWillChangeFrameNotification object:nil queue:nil usingBlock:^(NSNotification *notification) {
        @strongify(self);
        NSDictionary *keyboardAnimationDetail = [notification userInfo];
        
        CGRect keyboardEndFrameWindow = [keyboardAnimationDetail[UIKeyboardFrameEndUserInfoKey] CGRectValue];
        
        double keyboardTransitionDuration  = [keyboardAnimationDetail[UIKeyboardAnimationDurationUserInfoKey] doubleValue];
        
        UIViewAnimationCurve keyboardTransitionAnimationCurve  = [keyboardAnimationDetail[UIKeyboardAnimationCurveUserInfoKey] integerValue];
    
        CGFloat newConstant = (self.view.frame.size.height - keyboardEndFrameWindow.origin.y);
        self.pricingViewBottomSpaceToSuperviewConstraint.constant = newConstant;
        // if the height is too high (basically on iPhone 3.5"), remove title
        if (newConstant + self.pricingViewContainer.frame.size.height > self.view.frame.size.height - 20) {
            // remove constraint and update the alpha of the title to 0
            [self.pricingViewContainer removeConstraint:self.titleToQuantityPickerVerticalSpaceConstraint];
            self.titleLabel.alpha = 0;
        // if we are reversing the process
        } else if (self.titleLabel.alpha == 0) {
            [self.pricingViewContainer addConstraint:self.titleToQuantityPickerVerticalSpaceConstraint];
            self.titleLabel.alpha = 1;
        }
        [self.view setNeedsUpdateConstraints];
        [UIView animateWithDuration:keyboardTransitionDuration
                              delay:0.0f
                            options:((UIViewAnimationOptions)keyboardTransitionAnimationCurve << 16)
                         animations:^{
                             [self.view layoutIfNeeded];
                         }
                         completion:nil];
}];