当键盘在屏幕上并且用户选择预测开/关时，如何重新调整scrollview inset？

Question

我有下面的设置。当键盘在屏幕上时，将textFields移动到键盘上方是一件好事。在那个时刻，如果用户关闭预测键盘，则高度无法重新调整到新的keyboardFrame.height + 20（键盘和textField之间的额外填充）。当键盘在屏幕上并且用户在预测开/关之间切换时，什么是重新调整scrollView.contentInset.bottom的好方法？

ViewDidLoad：

NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillShow(notificaiton:)), name: .UIKeyboardWillShow, object: nil)

NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillHide(notification:)), name: .UIKeyboardWillHide, object: nil)

Oberservers：

//MARK: Keyboard Notifications 

func keyboardWillShow(notificaiton: Notification) {

    adjustKeyboardHeight(show: true, notification: notificaiton)
}

func keyboardWillHide(notification: Notification) {

    adjustKeyboardHeight(show: false, notification: notification)

}


private func adjustKeyboardHeight(show: Bool, notification: Notification) {

    let userInfo = notification.userInfo!

    let keyboardFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue

    if show {

        fgScrollView.contentInset.bottom = keyboardFrame.height + 20
    } else {

        fgScrollView.contentInset = UIEdgeInsets.zero
    }


}

//MARK: TextField Delegate
func textFieldShouldReturn(_ textField: UITextField) -> Bool {

    if textField == emailTextField {

       nextTextField.becomeFirstResponder()
    }

    textField.resignFirstResponder()

    return true
}

Answer 1

添加keyboardWillChangeFrame观察者，每次键盘框架改变时都会调用此标记

 NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChangeFrame(notificaiton:)), name: .UIKeyboardWillChangeFrame, object: nil)

    func keyboardWillChangeFrame(notificaiton : Notification ) -> Void {

          print("New frame of keyboard = \(notificaiton.userInfo?[UIKeyboardFrameEndUserInfoKey] ?? 0)")  

    }