使用 NSNotificationCenter 获取键盘高度，在 Swift 4.1 中不起作用

Question

我正在开发键盘扩展应用程序，我需要默认键盘的高度。

为了获得键盘的高度，我尝试了几十种解决方案like this，但从未调用过 Selector 函数。 还有其他方法可以找到默认键盘的高度吗？

Answer 1

此代码将显示您的键盘高度 -

func showKeyboard(notification: NSNotification) {
            if let sizeOFkeyboard = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
                let keyboardHeight = keyboardSize.height
            }
    }

Answer 2

这在 Swift 4.1 中非常适合我：

var keyboardHeight: CGFloat = 0.0

override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(true)

        // Register Notification, To know When Key Board Appear.
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: Notification.Name.UIKeyboardWillShow, object: nil)

        // Register Notification, To know When Key Board Hides.
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(true)

        // De register the notifications
        NotificationCenter.default.removeObserver(self)
    }

// MARK: - Keyboard Events

    @objc func keyboardWillShow(_ notification: Notification) {
        if let keyboardFrame: NSValue = notification.userInfo![UIKeyboardFrameEndUserInfoKey] as? NSValue {
            let keyboardRectangle = keyboardFrame.cgRectValue
            keyboardHeight = keyboardRectangle.height
        }
// use keyboard duration if needed (to animate your view)
        let keyboardDuration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as? Double

    }

    @objc func keyboardWillHide(_ notification: Notification) {

        let keyboardDuration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as? Double

    }