ios에서 키보드 팝업 감지

and와 다르게 ios에서는 webview의 text입력창에 포커스가 가 키보드가 올라오더라도 웹뷰가 줄어들지 않는다. 그래서 title이 안보이거나 bottom의 입력창이 가려지는 등의 문제가 있다. 이를 감지해서 웹뷰 사이즈를 줄여줄 때 이용

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(notification:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange(notification:)), name: NSNotification.Name.UIKeyboardWillChangeFrame, object: nil)

}    

@objc func keyboardWillShow(notification: NSNotification) {
    let keyboardSize = (notification.userInfo![UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue

        if keyboard == false{
            keyboard = true
            lastKeyboardHeight = keyboardSize.height
            chatDetailView.frame.origin.y = chatDetailView.frame.origin.y-(keyboardSize.height-bottomMenu.frame.height)
        }
    }

    @objc func keyboardWillChange(notification: NSNotification) {
        let keyboardSize1 = (notification.userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue

        if keyboard == true && lastKeyboardHeight != keyboardSize1.height {
            if lastKeyboardHeight < keyboardSize1.height{
                let keyboardDifference: CGFloat = keyboardSize1.height-lastKeyboardHeight
                chatDetailView.frame.origin.y -= keyboardDifference

            } else {
                let keyboardDifference: CGFloat = lastKeyboardHeight-keyboardSize1.height
                chatDetailView.frame.origin.y += keyboardDifference
            }
            lastKeyboardHeight = keyboardSize1.height
        }
    }

    @objc func keyboardWillHide(notification: NSNotification) {
        if keyboard == true {
            keyboard = false
            chatDetailView.frame.origin.y = chatDetailView.frame.origin.y+(lastKeyboardHeight-bottomMenu.frame.height)
        }
    }