计算键盘高度，而无需在Swift中使用NSNOTIFIENT

Question

我有一个很小的问题 - 我们可以使用通知计算键盘高度。所有股份溢出中的答案都是使用NSNOTIFIENT，但是是否有更简单的方法来计算它？

以下是代码：

 NotificationCenter.default.addObserver( self, selector: #selector(keyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil
@objc func keyboardWillShow(notification:  ) {
    if let userInfo = notification.userInfo {
        if let keyboardSize =  (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
            let kbHeight = keyboardSize.height
            }
        }
    }

代码在TextFieldDidBeginediting中使用键盘高度：

var kbHeight: CGFloat?

@objc func keyboardWillShow(notification: NSNotification) {
    if let userInfo = notification.userInfo {
        if let keyboardSize =  (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
            kbHeight = keyboardSize.height
            }
        }
    }

func textFieldDidBeginEditing(_ textField: UITextField) {
    if textField.frame.maxY > self.kbHeight!
    {
        self.scrollView.setContentOffset(CGPoint.init(x: 0, y: textField.frame.maxY - (self.kbHeight! + 2.0)), animated: true)
    }
    else{
        return
    }
    print(textField.frame.maxY)
    print(self.view.frame.height * 0.6)
    print(textField.frame.maxY - self.view.frame.height * 0.6)
}

func textFieldDidEndEditing(_ textField: UITextField)
{
self.scrollView.setContentOffset(CGPoint.init(x: 0, y: 0), animated: true)
self.view.endEditing(true);
}

Answer 1

实际上我没有任何直接获取键盘高高的想法。但是，当存在键盘时，您可以将键盘高度保存在变量中，并在您想要的地方使用

使用这两个观察者进行键盘并管理键盘Hight

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

必须在dinit方法中删除这些观察者，当时弹出或解散视图控制器。

deinit {
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: nil)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}

键盘通知的选择方法...

 @objc func keyboardWillShow(notification: NSNotification) {
    var keyBoardHeight: CGFloat = 0
    if let keyboardFrame: NSValue = notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue {
        let keyboardRectangle = keyboardFrame.cgRectValue
        keyBoardHeight = keyboardRectangle.height
    }
}
@objc func keyboardWillHide(notification: NSNotification) {
}