KeyboardAvoidance

KeyboardAvoidance.swift

extension ViewController {

		private func setNotificationForKeyboardAppearance() {
				NotificationCenter.default.addObserver(
						self,
						selector: #selector(self.keyboardWillShow),
						name: UIResponder.keyboardWillShowNotification,
						object: nil)

				NotificationCenter.default.addObserver(
						self,
						selector: #selector(self.keyboardWillHide),
						name: UIResponder.keyboardWillHideNotification,
						object: nil)
		}


		@objc func keyboardWillShow(_ notification: NSNotification) {
					if let chatViewBottomConstraint	{
						moveViewWithKeyboard(notification: notification, viewBottomConstraint: chatViewBottomConstraint, keyboardWillShow: true)
				}
		}

  
		@objc func keyboardWillHide(_ notification: NSNotification) {
				if let chatViewBottomConstraint{
						moveViewWithKeyboard(notification: notification, viewBottomConstraint: chatViewBottomConstraint, keyboardWillShow: false)
				}
		}


		func moveViewWithKeyboard(notification: NSNotification, viewBottomConstraint: NSLayoutConstraint, keyboardWillShow: Bool) {

				guard let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue) else { return }

				let keyboardHeight = keyboardSize.cgRectValue.height

				let keyboardDuration = notification.userInfo![UIResponder.keyboardAnimationDurationUserInfoKey] as! Double
				let keyboardCurve = UIView.AnimationCurve(rawValue: notification.userInfo?[UIResponder.keyboardAnimationCurveUserInfoKey] as! Int)!

				if keyboardWillShow {
						let safeAreaExists = (self.view?.window?.safeAreaInsets.bottom != 0)
						let bottomConstant: CGFloat = 20
          
          #warning (" CHANGE THE BOTTOM CONSTRAINT HERE ")
          
						chatViewBottomConstraint?.constant = -(keyboardHeight + (safeAreaExists ? 0 : bottomConstant))
				} else {
						chatViewBottomConstraint?.constant = -20
				}

				let animator = UIViewPropertyAnimator(duration: keyboardDuration, curve: keyboardCurve) { [weak self] in
						self?.view.layoutIfNeeded()
				}

				animator.startAnimation()
		}
}